Category: Dogs

Addison’s Disease (hypoadrenocorticism)

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This disease of the adrenal glands of dogs (it’s very rare in cats) involves inadequate hormone levels of cortisol (cortisone) and electrolytes (sodium and potassium). This unusual disease can show a vast array of different symptoms, symptoms that mimic other diseases. There is even a version of this disease called “atypical”, which adds to the complexity. Because there can be such a variety of symptoms, Addison’s disease is sometimes known as the great pretender or great imitator. In any dog that is ill, our veterinarians need to keep this disease in mind.

Addison’s is named after a physician in 1849’s who discovered this disease. President John Kennedy suffered from the human version of this disease.

Addison’s disease is the opposite of another problem with the adrenal glands called Cushing’s Disease (hyperadrenocorticism). In Addison’s there is not enough cortisol, in Cushing’s, there is too much cortisol.

We have an interesting page on adrenal disease in ferrets, which causes different symptoms in the ferret compared to dogs and cats.

Nomenclature

Several medical terms and abbreviations relate directly to Addison’s:

glucocorticoids – Cortisol tachypnea-increased respiratory rate
exogenous cortisone– supplemental cortisone by mouth or injection bradycardia-abnormaly slow heart rate
catabolic steroid– cortisol and its equivalent polyuria– excess urinating
anabolic steroid– opposite of catabolic, testosterone is the most common one polydipsia– excess drinking
hyperkalemia- high potassium (K) level in the bloodstream PU/PD– polyuria and polydipsia
tachycardia -abnormally fast heart rate mineralcorticoid-hormone that affects sodium and potassium
hypoglycemia– low blood glucose (sugar) level iatrogenic– caused by something a person does as opposed to happening naturally.
hyponatremia- low sodium (Na) in the bloodstream ACTH– adrenocorticotrophic hormone
atrophy-an  organ that is smaller than it should be adrenomegaly– enlarged adrenal gland
anemia– low red blood cells microcardia- small heart
cortisol– Cortisone made by the adrenal glands  azotemia– elevated BUN and creatinine

Adrenal Gland Anatomy

The adrenal glands are paired organs that lay right in front of the kidneys on each side. They are quite small, and measure only a few millimeters in length. This small size is not an indication of their importance though. Even though they are small, the cortisol (cortisone) they secrete, along with their other functions, have great significance to normal physiology.

The arrows point to the paired adrenal glands in front of each kidney. The extensive blood supply to the kidneys and adrenal glands is apparent. In the diagram they are easy to see. They are not so easy to see during ultrasound or exploratory surgery because normally they are small and buried in fat. They do not show up on an X-ray unless they are calcified or much larger than normal.

This is a picture of an enlarged adrenal gland (arrow) that is buried in fat near the kidney (K). It is from a ferret that has an adrenal gland tumor, so the adrenal gland is inflamed and easily visualized. This is not necessarily the case in dogs and cats that have adrenal gland tumors.

The internal architecture of the adrenal gland is made up of several distinct zones.

Cortex

The cortex (outer shell) of the adrenal gland is made up of 3 anatomical parts:

Zona Glomerulosa

This is the outer layer of the adrenal gland. This section secretes the mineralcorticoid aldosterone. Aldosterone is vital to proper sodium and potassium regulation. Aldosterone has a role in maintaining  blood pressure.

Zona Fasciculata

This is the next layer as you go inward, and produces the glucocorticoid cortisol. The cells in this area are the ones that cause Cushing’s when they secrete cortisol in excess.

Zona Reticularis

As we continue inward we come across this section that secretes the sex hormones known as androgens (male sex hormones), estrogen (female sex hormones), and sex steroids. These are usually secreted in such small amounts as to be of no major significance in healthy animals. The gonads in dog and cats secrete most of the sex hormones.

Medulla

This consists of the very center of the adrenal gland. It secretes hormones called catecholamines. The two important ones are epinephrine (adrenaline) and norepinephrine.

Physiology

The tiny adrenal glands have a profound influence on many internal organs. The hormones they secrete work in unison with other hormones and internal organs, particularly the liver, and have an enormous effect on physiology. These hormones interact with many other hormones that have the opposite effect, usually in some type of feedback mechanism that is monitored by the brain. This interaction is complex, so only a summary of adrenal hormone physiology is presented.

The adrenal glands secrete several important hormones, most of which are synthesized from cholesterol. We will explain 3 of them; cortisol, aldosterone, and epinephrine:

Cortisol

Cortisol maintains a normal blood glucose level, facilitates metabolism of fat, and supports the vascular and nervous systems. It affects the skeletal muscles, the red blood cell production system, the immune system, and the kidneys. Obviously, it is a very important hormone, and necessary for life.

It is considered a “catabolic steroid”. This means it takes amino acids from the skeletal muscles and, and with help from the liver, converts them to glycogen, the storage form of glucose. These functions are the exact opposite of “anabolic steroids”, the drugs that weight lifters take to increase muscle mass. The end result of this is an increase in the level of glucose in the bloodstream. The hormone called insulin has the opposite effect on blood glucose, adding to the complexity of this system. You can learn more about insulin by going to our diabetes mellitus page.

The level of cortisol in the bloodstream continually fluctuates as physiologic needs vary. Surgery, infection, stress, fever, and hypoglycemia (low blood sugar) will cause cortisol to increase. This continual fluctuation adds to the difficulty of diagnosing any disease involving cortisol (Addison’s and Cushing’s), because the amount of cortisol in the bloodstream is so variable.  A test taken at one moment in time might have different results if taken later.

To control the level of cortisol the hypothalamus and pituitary gland in the brain secrete chemicals into the bloodstream called releasing factors. In the case of the adrenal glands , the hypothalamus secretes a hormone called corticotropin releasing hormone (CRH). This hormone goes to the pituitary gland and stimulates it to release a hormone called adrenocorticotrophic hormone (ACTH). It is the amount of ACTH circulating in the blood stream that tells the adrenal glands (specifically, the cells at the zona fasciculata) how much cortisol to secrete. There is a negative feedback loop that allows the hypothalamus and pituitary gland to refine precisely how much cortisol circulates in the bloodstream. The more cortisol secreted by the adrenal glands, the less CRH and ACTH secreted. This allows the body to precisely refine the level of cortisol, and to change the level rapidly due to changing physiologic needs.

This negative feedback mechanism is a highly profound adaptation to evolutionary pressures, and is the basis for our survival as a species. Without this, life as we know it, would not exist for us and many species on this planet.

Numerous organ systems are affected by cortisol:

Musculoskeletal

Cardiovascular

Skin

Renal

Gastrointestinal

Immune

Mineralcorticoids

Aldosterone is the principal mineralcorticoid secreted by the adrenal glands. This hormone is secreted as a response from the kidneys when fluid volume in the bloodstream is decreasing. It involves other hormones called renin and angiotensin. The end result is an increase in sodium in the bloodstream, with a corresponding increase in blood volume and blood pressure. This increase in blood volume and pressure is because  sodium  pulls fluid from the intestinal tract, and the area around each cell called the extracellular fluid, into the bloodstream.

This hormone also interacts with and affects potassium levels. To further complicate the picture, ACTH also has an affect here, just like it does with cortisol.

Epinephrine (Adrenaline)

This compound, technically called a neurotransmitter, also has hormone-like properties. It is a very powerful chemical that affects all organ systems. It acts very rapidly, with effects remaining only for a short period of time. It is the primary reason the body has the ability to respond to an emergency. This physiologic mechanism is also known as the “flight or fight” response.

Upon stimulation of the central nervous system (ex.-fear or pain), the adrenal medulla is stimulated to secrete epinephrine into the bloodstream. We are all familiar with what happens next. The pupils dilate, the heart rate and blood pressure increase, and the palms get sweaty. Internally, the body is increasing the blood glucose level, the breathing passages are opened up, more red blood cells are secreted into the circulation, blood is shunted away from the skin and other internal organs, and blood flow is increased to the brain and skeletal muscles. All of this has the effect of bringing the brain and skeletal muscles extra glucose and oxygen, and accounts for the extra boost of awareness and energy we all feel at this time. For such a small set of organs it is apparent that the paired adrenal glands have a very important role in normal health.

Pathophysiology

When the disease affects the part of the adrenals that secrete cortisol (the zona fasiculata) a vast array of different symptoms can occur. This is because of the profound effects cortisol has on almost all body systems.

When the disease affects the part of the adrenals that secrete aldosterone (the zona glomerulosa), then electrolytes like sodium (Na) and Potassium (K) are affected.

The overwhelming majority of the adrenal cortex must be affected before it secretes inadequate amounts of cortisol and aldosterone and before any symptoms are noted.

There are 3 forms of this disease:

Primary Hypoadrenocorticism

 This classic form of the disease is due to a lack of both mineralcorticoids and glucocorticoids. The zona fasiculata and the zona glomerulosa are both involved. This means the problem is at the adrenal gland itself.

Causes:

Immune system destruction of the adrenal gland due to autoantibodies is the most common cause

Medication to treat Cushing’s disease (mitotane or trilostane)

Infection

Coagulation disease

Cancer

Loss of blood supply to the adrenal gland (an infarction)

Secondary Hypoadrenocorticism 

This more unusual form of the disease occurs when the zona fasiculata only is involved. This means the problem is at the pituitary and not at the adrenal gland, therefore only cortisol production is compromised and the electrolytes sodium and potassium are not affected.

Causes:

Abruptly stopping oral or injection cortisone that has been administered for a period of time (exogenous cortisone)

Congenital defects of the pituitary gland

Cancer or trauma to the hypothalamus

Atypical

This includes all of the dogs classified as secondary, so only cortisol is involved. In these dogs electrolytes are normal,  just like in secondary hypoadrenocorticism. What makes this atypical is that fact that many dogs might change to primary during the course of the disease. Only then will the electrolytes  be involved.  This can make treatment difficult, because a pet that is being treated successfully for secondary might need to be treated for primary at some point. This emphasizes the need for close monitoring with blood panels and exams at least every 6 months.

Diagnosis

Signalment

Usually found in female dogs that are middle aged or less. It is more commonly found in dogs that are not spayed (ovariohysterectomy).  Atypical Addison’s tends to occur more in the older dog. Certain breeds get this disease more often than others:

  • Great Danes
  • Standard Poodles
  • Bearded collies
  • Portugese water dogs
  • Rottweilers
  • Wheaten Terriers
  • West Highland White Terriers (Westies)

History

Symptoms are quite variable, and can come and go over months.  As a result, it is easy to miss this disease or get it confused with other diseases that have the same symptoms. Symptoms might be mild, or they might be life threatening, and can be found in many other diseases.

In some cases, a pet has been ill in the past, and treated with fluids with a successful outcome, and now the problem has returned. A blood panel in this situation might show a kidney problem due to dehydration, which is why the fluids helped. If this is a recurring problem, Addison’s should be tested for.

Typical symptoms might include:

  • lethargy
  • inappetence
  • weight loss
  • diarrhea or dark stools
  • vomiting
  • shaking
  • dehydration
  • shock
  • collapse
  • drinking and urinating more than usual (PU/PD)
  • abdominal pain
  • seizures if severely low blood sugar is present

Physical Exam

Just like the symptoms above, the physical exam of a dog with this disease can be quite variable. Typical exam findings we might encounter include:

  • depression
  • pale gums
  • tacky gums
  • panting
  • hair loss
  • weak pulse
  • increased heart rate (tachycardia) if shock
  • decreased heart rate (bradycardia) if potassium is high
  • increased respiratory rate (tachypnea)
  • low body temperature
  • painful abdomen upon palpation

Diagnostic Tests

Radiography

X-rays might be helpful in diagnosis, although they are not the primary way this disease is diagnosed. On a radiograph we might find a small heart and liver due to dehydration and shock. On rare occasions megaesophagus (enlarged and non-functional esophagus) might be present. None of these symptoms are diagnostic of Addison’s by themselves, since numerous other diseases can cause these symptoms.

.

The heart is the white object in the center of this radiograph. Compared to the heart in the radiograph below it is small, which might indicate dehydration due to Addison’s. 

The adrenal glands do not show up on an abdominal radiograph unless they are calcified or extremely enlarged, which would be more indicative of Cushing’s and not Addison’s.

Electrocardiogram (ECG)

If the potassium is high enough (hyperkalemia) the heart rate might be slow (bradycardia) and there might be changes in the electrocardiogram. There are other causes of hyperkalemia, so this is not diagnostic for Addison’s, it is a clue that Addison’s might be present. The most common cause we see for hyperkalemia is a cat that cannot urinate in the obstructed version of FLUTD (Feline Lower Urinary Tract Disease).

Below is a normal ECG strip for 4 beats of the heart. Below the strip is an enlargement of one beat.

If hyperkalemia is significant, changes to the ECG might include:

  • slow heart rate (the 4 beats below might only be 2-3 beats)
  • absent P waves
  • widening (prolonged) QRS complex
  • Shorter (decreased amplitude) R wave

EKG

Ultrasonography

Ultrasonography would usually show small adrenal glands, although a dog can have Addison’s and have normal adrenal glands on ultrasound. The adrenal glands in Addison’s are tiny, and can be difficult to find in some cases.

OLYMPUS DIGITAL CAMERAThis is a normal right adrenal gland enlarged for easier viewing. It is marked by the + signs.

Tuffy3

This is a small left adrenal gland like we might find in Addison’s. It is the whitish area in the center towards the top with the dark area in the center. It takes an experienced ultrasonographer to find a small adrenal gland.

Blood Panel

Blood work (chemistry and complete blood count) is a crucial component for detection of this disease. Common abnormalities might include one or more of these findings:

  • anemia (low red blood cells)
  • increased eosinophils and lymphocytes
  • low blood sugar (hypoglycemia)
  • azotemia (high BUN and creatinine)
  • hypercalemia (high calcium)
  • hyperkalemia (high potassium)
  • hyponatremia (low sodium)
  • hypochloremia (low chloride)
  • increased liver enzymes (ALT)
  • increased alkaline phosphotase (ALP)
  • hypoalbuminemia (low albumin)
  • hypercholesterolemia (high cholesterol)
  • low ratio of sodium (Na) to potassium (K). If the ratio is less than 27:1, and the history and symptoms are consistent with this disease, then a high index of suspicion is appropriate.

Cortisol decreases the blood flow (also called GFR-glomerular filtration rate) to the kidneys. This will result in an decrease in the amount of water and waste products filtered by the kidneys. On the blood panel this might show up as kidney disease, when in reality it is Addison’s. Our kidney disease page has more details.

Each of the following blood panels was taken from a dog with Addison’s. They are all different, a testimony to how variable this disease can appear on a blood panel. When coupled with the wide variety of symptoms, that can wax and wane, a diagnosis of this disease is not black and white.

 In this first blood panel, the only abnormal finding of significance is the low RBC, HGB, and HCT. This means the pet has anemia.

Notice how these tests are mostly normal, although this dog has Addison’s

BuddyHansonBlood

In this dog with Addison’s, the chloride, sodium, and glucose  are low. The Na/K ratio is OK.

Tuffy2

This dog with Addison’s has numerous abnormalities, this time including a low Na/K ratio

Special Tests

Cortisol level

In this test a baseline cortisol level is run by taking a blood sample.  If the baseline cortisol is over 2 mcg/dl (micrograms per deciliter) then the dog does not have Addison’s. There is no need to go any further since Addison’s is not involved at this point. If the baseline cortisol is less than 2 mcg/dl then we will do the ACTH stimulation test.

ACTH Stimulation test

Diagnosis is confirmed with an ACTH (adrenocorticotrophic hormone) stimulation test. This test is also used to help diagnosis the opposite problem of Addison’s disease, which is called Cushing’s disease.

ACTHgel

Once the baseline blood cortisol is obtained we give an injection of a specific amount of ACTH. One hour later we take another blood sample to check if the cortisol level has changed. We get the reports from the lab usually the next day.

If the baseline cortisol is less than 2 mcg/dl, and it does not increase on the blood sample taken one hour later after we have injected ACTH, then the disease is confirmed.

Addison's-4

Akita’s and Shiba inu’s sometimes have elevated potassium levels on blood tests. This can be very confusing when a patient has symptoms that suggest Addison’s disease. The ACTH Stimulation test will let us know if they have Addison’s.

An occasional dog will be presented with symptoms consistent with Addison’s, including abnormal sodium and potassium levels. These dogs might have Whipworms and not Addison’s. Again, the ACTH Stimulation test will let us know if they are Addisonian. We have a page on internal parasites that includes Whipworms.

Treatment

Acute Phase

In the acute phase, dogs are presented collapsed and in a state of shock and hypothermia. They need shock doses of intravenous fluids and injectable cortisone (dexamethasone) along with warmth. If the hyperkalemia is causing bradycardia, the IV fluids usually suffice.  If not, insulin needs to be administered. If hypoglycemia is present, dextrose is added to the IV fluids.

Chronic Phase- Most dogs are presented in this phase

For low cortisol we use prednisone orally at a relatively low but consistent dose. Any pet with chronic Addison’s needs to have this dose increased when there is a stress like fireworks, going to the groomer or veterinarian, or anything in general that causes extra stress.

We will test the blood every 6 months at the least to make sure there are no serious side effects to this use of cortisone. For the majority of dogs, there are no side effects, and the drug is mandatory for treatment of this disease. The symptoms of the disease, and their potentially life threatening nature, far outweigh side effects when used under our supervision.

Prednisone

Prednisone and prednisone are tried and true drugs that have been used to treat this disease for many decades

For an imbalance in electrolytes we use one of two drugs, although the injectable version is much more convenient and very effective:

Percorten-V (DOCP)Percorten-V works extremely well for most dogs and allows them to lead a normal quality of life. This injectable medication is given every 25 days for the majority of dogs. We will test the electrolyte levels with a blood panel early in the course of treatment to monitor Na and K levels and adjust the timetable accordingly. We will then test the blood at least every 6 months.

Percorten

Harmony is drawing up Buddy’s Percorten

Addisons-HarmonyInjection1

Buddy comes in every 25 days on the dot, and after his pinprick injection (we use a 25 gauge needle so it is jut a pinprick) he is good to go for another 25 days.

Addisons-HarmonyInjection2

Florinef – It does have some cortisone properties, and in some cases a dog does not need prednisone when on this drug. This does not apply to stressful situations, and additional medication in the form of prednisone tablets is always needed.This oral medication has fallen out of favor as a treatment because it has to be given daily, and some dogs develop a resistance wherein the dose has to be increased.

Florinel

The pills are small and easily given

Prognosis

This is a hormone disease, which means it is part of a highly tuned and refined mechanism that is in constant state of change. Vigilant monitoring is of essence for a successful outcome. We have numerous dogs at our hospital currently being treated successfully with prednisone and Percorten-V over many years. These dogs are leading a normal life, and you would have no idea they have a serious hormone disease when you see their owners bring them into our hospital or take them for a walk.

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Arthritis

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One of the most insidious diseases we encounter in animals is arthritis. It was not long ago that pets were euthanized because they seemed “old” based on their symptoms of poor appetite, decreased activity, and lethargy. In reality they were not “old”, they had arthritis, and acted like they were old because they were painful.

Today we can treat their arthritis and give them a new lease on life and lead a great quality of life for many more years. All animals get arthritis, we most commonly see it in dogs and cats. This page will emphasize it in dogs since it is most prevalent in them. Cats get arthritis also, and we wil discuss how they differ from dogs in this disease.

Many of our pets are stoic, and can have a disease process brewing on the inside yet show no external symptoms. As the disease progresses eventually the symptoms appear, and we are presented with a very ill pet that seemingly became sick overnight. The reality is that the problem was present for a long period of time. It went unnoticed until your pet went rapidly downhill, when the bodies mechanisms for compensating and coping with the disease have become overwhelmed, and your pet is in a debilitating condition. At this point the disease process is so well entrenched that the prognosis for recovery is poor.

This concept applies to arthritis in dogs and cats.With our new digital radiography that gives us much more detail, we are diagnosing it earlier. Coupled with substantially improved treatments, we can successfully treat these arthritic and painful animals, and give them a vastly improved quality of life for many more years.

This digital radiograph of the abdomen shows the tremendous detail we get with digital, and how we can see the internal organs in the abdomen. Click on the photo above if you would like to learn how to read a radiograph (you do know the 5 radiographic densities don’t you?).

What’s even better is the fact that some of these new treatments do not involve the use of drugs. We have a multi-system approach to arthritis due to its chronic and debilitating nature, and the fact we strive for treatment modalities that involve minimal use of long term drugs.

Here is a summary of how we approach this important problem. We will talk about these treatments in more detail later in this page:

If your pet is overweight, a common problem, modifying diet and feeding habits to bring it back to its fighting weight can minimize the symptoms of arthritis. This common sense, inexpensive, and drug free option, seems to escape many people.

Hills-MetabolicMobility

Hill’s makes a prescription diet called Metabolic + Mobility that addresses obesity and arthritis at the same time. It is the food of choice for overweight dogs that that are also arthritic.

Arthritis tends to be a disease of the aging. Older pets have different nutritional needs that need to be addressed. These needs cannot be addressed by going to a pet store and listening to the advice of some amateur nutritionist behind the counter trying to sell you the latest gimmick in dog food marketing. It comes after you discuss your pet’s individual lifestyle needs with your veterinarian, your pet is given a thorough physical exam, and your veterinarian has blood panel and radiographic tests on your pet. Only then will the full picture of your pets needs be understood, leading to a custom treatment protocol specific for your pet.

Chondroprotective agents called neutraceuticals can help in some cases.  These are the chondroitin sulfate- glucosamine products available everywhere, including Trader Joe’s at the checkout stand. They are not a panacea, and its important to take a critical look to see if they are working in your pet’s case. Sometimes the placebo effect seems to be transmitted in our minds to our pets, and we do not have an objective standard to determine if these medications truly help. Fortunately they do not seem to hurt, so we can achieve or first goal of “do no harm” as veterinarians.

NSAID’s  (non-steroidal anti-inflammatory drugs) are a tremendous advancement in the treatment of arthritis. Non-steroidal means they do not contain cortisone, which was one of the primary drugs used to treat arthritis in the recent past. The NSAID’s are better at treating arthritis when used judiciously to maximize their good effects, while minimizing their potential for side effects. Every pet reacts differently, so if one NSAID does not seem to work, we will try another. In cat’s we use this drug sparingly if it all due to their inabiliy to tolerate their use long term. The NSAID’s we use in cats are called Meloxicam, Metacam, or Onsior.

Veterinary Neuronal Adjustment (VNA or VOM) is a tremendous treatment modality that uses the bodies natural healing processes without the use of any drugs. It involves stimulating the autonomic nervous system (specifically the sympathetic branches) and provides substantial pain relief. We have been using VNA at the Long Beach Animal Hospital for over 15 years. This is especially important in cats, since they do not tolerate NSAID’s well for long periods of time.

Therapy Laser brings an additional and highly effective treatment modality that again does not involve the use of drugs. This laser penetrates the hair and skin and goes right to the problem area to decrease inflammatory mediators. We recently updated our equipment to include a new therapy laser called MLS that treats using two different wavelengths.

Acupuncture can also be used to augment all of the above therapies. Dr. Seto and Dr. Yamamoto are both certified in acupuncture in animals. Cats do well with acupuncture.

Stem cell therapy is starting to be used, utilizing your dogs own fat cells. It is still in the early stages, and treatment is not long lasting. If this area of treatment evolves and becomes more practical, we will utilize it.

Exercising your pet in the cooler part of the day, without excess trauma like jumping for long periods of time, will keep your pet flexible, the joins warm and lubricated, and keep its weight under control. If your pet is not afraid of water, letting it swim in a shallow area is a great way to enhance mobility.

In older cats that are prone to arthritis there are several common sense things to do:

Raise the water and food bowls slightly. This is because cats get arthritis in the elbow joint, and elevated bowels allow them to feed with the elbow in extension, which is less painful. It also gives cats with hip and stifle (knee) pain are more comfortable sitting position when feeding.

Have several litter boxes around the house, make sure they do not need to go up the stairs to access them, and if the litter pans have tall sides see if they can be cut down for easy access.

If your cat likes to perch on a window sill or lay on your bed make sure it does not need to jump to access these areas, and set up some steps for easy access.

We will use the words arthritis and osteoarthritis (OA) interchangeably, because they are the same thing in regards to the pain your pet is feeling and how it is treated.

Please be realistic about the fantastic claims that abound on the Internet for cheap treatments that will help your pets arthritis. These treatments have show to be nothing more than effective marketing. This disease is complicated and serious, and needs more than some supplement you purchase online.

What is Arthritis?

Dogs are prone to many different types of bone problems. This page will focus on the arthritis that tends to occur in dogs, especially as they age. Arthritis literally means inflammation of the joint, but the term is used more generally to describe several different processes. These include degenerative joint disease (DJD), infectious joint disease, immune mediated joint disease, and crystal-induced joint diseases. Many people use the term arthritis synonymous with osteoarthritis (OA), a complex, slowly progressive, and degenerative arthritis that is characterized by the gradual development of joint pain, stiffness, and a decreased range of motion.This is the type of arthritis common in older pets, and is increasing as pets live longer.

As we learn more about the subtleties of feline medicine we realize that many cats get significant arthritis especially in their lower back. This problem, also know as feline hypersethesia syndrome, causes tremendous discomfort and decreases the quality of life for many cats.

Anatomy

A normal joint is lined with hyaline cartilage, which is the covering over the end of the bone. It provides an almost frictionless surface for the bones to articulate, and also acts as a shock absorber. Hyaline cartilage is comprised of chondrocytes, proteoglycans, and collagen.

A normal joint is encased in a fibrous structure called the joint capsule. The joint capsule helps stabilize the joint and keeps the cartilage bathed in synovial fluid. Ligaments, which attach bone to bone, also provide joint stability.

This picture is from an actual surgery on the knee of a dog with a ruptured cranial cruciate ligament. The head is on the right, the foot is on the left, so the joint appears horizontal.

Arthritis-StifleJointArrow

The ridge of bone running horizontally at the bottom (arrow) is arthritis. The normal smooth cartilage above it is the normal groove of the knee (stifle) joint. The patella runs along this groove. 

Cause

The cause of this complex and multi factorial disease can be primary or secondary. Primary OA results from normal stresses acting on abnormal cartilage. Secondary OA is more common, and results from abnormal stresses acting on normal cartilage, such as an unstable joint caused by canine hip dysplasia, fragmented coronoid process, ununited anconeal process, patellar luxation, or a ruptured cruciate ligament. Some of the factors that can cause OA include excessive exercise, obesity, poor nutrition, trauma, immune reactions, and genetic predispositions.

The  following radiograph on the top is from a normal shoulder joint. The one on the bottom has an abnormal flap of cartilage at the arrow. This is know as osteochondritis dissecans, and is a primary OA. Without this radiograph we never would have know this limping pet had this problem.

shoulder arthritis

This normal shoulder joint shows no problems
osteochondritis

The white arrow points to a flap of cartilage that has eroded off

These two elbows from the same dog are normal

This elbow from a different dog shows advanced arthritis, probably secondary to elbow dysplasia

Damage to cartilage might occur as one event, or be the culmination of many small events over years. As swelling occurs, and the joint capsule becomes stretched, pain occurs. Your pet will use the joint less because of this pain, leading to muscle atrophy and the inability of the surrounding tendons and muscles to support the joint. As the muscular support of the joint weakens the joint capsule, ligaments, and cartilage become further stressed and stretched, leading to even further pain.

At this point the body releases chemicals called inflammatory mediators, (the therapy laser works on these mediators) which further damage the cartilage and add to even more swelling. It is obvious that this rapidly becomes a vicious cycle leading to debilitating pain. When OA progresses to the point that you notice your pet in discomfort or pain, the damage to the joint might be irreversible.

Diagnosis

Signalment

OA is commonly diagnosed in older dogs and cats. Some breeds are prone to getting it because of the conformation of their joints.

Dogs like Dachshunds have abnormally shaped long bones that might predispose them to OA. This is the wrist, forearm, and elbow of a Doxie. The medical terms are carpal, radius, ulna, and olecranon.

History

It is important to understand the initial symptoms might be subtle. Your pet will be experiencing pain or discomfort, yet it might not show any external signs.

Symptoms are related to joint pain and stiffness. Most owners notice a pet losing its ability to perform normally, such as a reluctance to jump or climb stairs, or even limping. Stiffness after rest that diminishes rapidly as your pet starts moving and warms up is a hallmark sign of OA. Other symptoms of arthritis include lethargy and poor appetite, which are the result of pain.

Initial symptoms are subtle and easily missed. Most dogs show a reluctance to run or move about. Some might not walk as long as usual, stop part way through a walk, or come back from a routine walk and go right to their bed to rest. They might be slow getting up.

Some will be reluctant to go up or down stairs, or might even be limping. As the disease progresses these dogs might be in overt pain and lose their appetite. Some of these symptoms occur in other diseases, notably hip dysplasia and intervertebral disk disease. The are treated in similar ways in some cases, in different  ways in other cases, so a proper diagnosis is imperative.

Dogs that will not go on extended walks, or dogs that pant excessively during a walk could also indicate OA. Symptoms can be worsened by obesity, too much exercise, and by cold or damp conditions.

Cats tend to show different symptoms sometimes. The most common areas for cats to have arthritis are the elbow, knee, hip, and spine. Most cats tuck their forelimbs under their bodies when they rest. If your cat consistently holds its elbow out (in extension) that could be a sign of elbow pain, a common area for arthritis to occur in cats. Cats that are reluctant to jump up to the bed or a window sill could have arthritis.

Other symptoms in cats include unkept fur due to pain when grooming. There could be overgrooming in painful areas leading to hair loss at the joints. Overgrown claws could be a sign it is not moving normally due to pain. At the end of this page is a link to the Feline Musculskeletal Pain Index to help determine if your cat is having a problem.

Physical Exam

In some pets there are no abnormalities detected during a physical exam. Pain or discomfort might be found by palpating a joint or pushing on the mid or lower back. We might feel grinding of joints (crepitus), a swollen joint, abnormal bone formation and roughened bones, or inflammation at the joint. Dogs with longer standing OA might show atrophy of muscles. Range of motion might be limited and cause discomfort or pain. There might also be subtle signs during the neurologic part of the exam.

Cats tend to have less crepitus and range of motion problems, but do have more joint swelling and pain.

Some pets are so distracted during an exam (this happens to us people commonly) that they do not exhibit signs of pain when touched in painful places. This is why we need some basic diagnostic tests.

Diagnostic Tests

Radiography is an important diagnostic test to perform on a dog or cat suspected of having OA. Even though a radiograph can be normal in a pet that has OA, it is a substantial help in verifying the diagnosis and determining the degree of involvement. Cats tend to have less radiographic evidence of arthritis, and might even have more cartilage problems than bone problems in some cases.

There are many diseases that can mimic the symptoms of OA, so a radiograph should be taken on every suspected OA  to eliminate these other causes.

This is a normal dog knee joint radiographically

This one has arthritis. The arrows point to all of the rough edges that are indicative of OA. Compare these rough edges to the smooth edges on the radiograph above. Also, the bone has a stronger whitish appearance, another indication of OA. You saw what this looks like on the picture of the knee joint above.

This dog was originally suspected of having arthritis based on a history of soreness in the hip area. It would be a mistake to treat this dog with an arthritis supplement and let the undiagnosed problem progress.

Radiographs revealed the true diagnosis was not the assumed arthritis, as can be seen at the arrow at the far left of the radiograph. The white circular area in the bone has the potential to be several different diseases, some of them serious like cancer.  A bone biopsy is need to know for sure.

A close-up view gives you a better idea of this dog’s problem

This form of OA is called spondylosis, which is arthritis of the vertebrae in the spine.
It is very common as pets age and causes substantial discomfort, nerve weakness, and even urinary and bowel incontinence.

This 12 year old Chihuahua has severe spondylosis throughout its lumbar vertebrae

The red circles show the sever spondylosis this bulldog has. The lumbo-sacral (called L-S) spondylosis on the right is very painful.  It is affecting the nerves to the bladder, causing an inability to properly urinate. The hugely distended urinary bladder is the result of this nerve problem, and can be seen as the large whitish area in the center of the radiography. A bladder this large is painful and prone to a chronic infection (UTI or cystitis).

You can learn more about the bones of the spine by going to our intervertebral disk page.

This dog was sore around its rear quarters when petted by the owner. The owners of the dog assumed it was arthritis and treated the problem on their own. When it did not improve the dog was brought to us for a proper diagnosis. Look at the lateral radiograph below of its posterior abdomen and see what you think the cause of the soreness was.

Did you figure out what is going on? Those circular white objects towards the top right of the radiograph are 3 pennies in the rectum! Even though it seems like a safe place to store your money, it was painful and causing this dog’s problem.

This is another dog that was sore in its rear quarters which that owner (and all of his well intentioned friends that love to give advice) assumed was just old dog arthritis. The circle shows the real cause of the problem in this dog’s back end. It is due to enlarged sublumbar lymph nodes from malignant cancer. 

A very important differential when diagnosing OA on a radiograph is a bone tumor. This one is on the femur (thigh bone). This dog had symptoms of muscle atrophy and limping on this leg. If a radiograph had not been taken these symptoms could have easily been mistaken for arthritis. At this stage of the disease amputation is usually the only way to temporarily stop the tumor from spreading.

This is a serious form of cancer, and usually requires amputation 

The other important differential on radiograph like this is a bone infection called osteomyelitis. The fuzzy or roughened edges at the arrows is the infection.

The incorporation of digital radiography into our practice gives us substantially more detail on a radiograph. This is easily seen in the Ferret spine radiograph.

Treatment

Treatment of OA initially includes correction of any underlying primary diseases such as surgical correction of a torn ligament or arthroscopy to remove a cartilage flap. Once any primary disease has been addressed, the goal of treatment is to slow the progression of OA and to keep your pet comfortable. It’s important to realize that there is no cure for OA. The following are the treatment options we find that are most successful, and were mentioned at the beginning of this page.

Nutrition

Most pets with OA will require some adjustment in their lifestyle. Weight management is most important, since obese pets put unnecessary strain on joints, leading to a more rapid progression of the disease. Depending on the degree of obesity your veterinarian might put your overweight pet on Hill’s Metabolic Diet. This is a weight control product with lasting effects and is our first recommendation. We might also use Hill’s W/D (weight diet) or Hill’s R/D (reducing diet).

If your pet is not overweight  we will utilize a food called Hill’s J/D (joint diet). It has added chondroitin sulfate and glucosamine in addition to essential fatty acids and carnitine. These foods are complete and balanced nutrition and can be fed for the rest of your pets life. There is a version for dogs and one for cats. Like all Hill’s foods it highly recommend in almost every case of arthritis unless your pet has some other disease that precludes their use. All Hill’s Prescriptions Diets our doctors recommend are unconditionally guaranteed. We have a detailed page on Nutrition Advice to help clear the air on all the hype that exists on the Internet to get you to put your money into this multi billion dollar a year business.

Omega-3 fatty acids have been shown to improve activity in cats with arthritis. They are included in many health diets already, so added amounts are not needed in most cases.

Exercise

Excessive exercise that leads to pain or discomfort should be avoided, but moderate exercise is recommended. Swimming is an excellent exercise for pets that have OA and aren’t fearful of water. Most pets do best with several short, exercise periods per day rather than fewer extended periods. Each patient will have their own unique program of weight management and exercise, and we can help you individualize one for you and your pet.

There are even veterinarians that specialize in rehabilitative therapy, with specialized swimming pools and therapy methods.

Chondroprotective Agents

These products typically contain precursors of cartilage and joint fluid synthesis. We like to use these medications first since there are negligible side effects and they might be an aid in preventing further deterioration of the cartilage. Hill’s J/D contains adequate amounts of these ingredients. Please remember that if a little is good, a lot is not necessarily better, because you disrupt the nutrient balance that is so important in nutrition.

These products have a positive effect on cartilage matrix synthesis and  an inhibitory effect on the enzymes that break cartilage down. They might require up to 6 weeks of use before OA symptoms are diminished. Unfortunately they do not work in every case, so be realistic and make a careful assessment as to their efficacy.

Adequan

Adequan (polysulfated glycosaminoglycan) is an injectable chondroprotective agent. Adequan incorporates into joint cartilage and inhibits several enzymes that break down cartilage. No studies have been done in animals other than horses and dogs, but it appears to be safe and effective in other species including cats, rabbits, ferrets, and birds.

The intramuscular injections are initially given twice weekly (every 3-4 days) for a month, then given monthly as needed. Adequan seems to be most effective when given in the early stages of OA. 

Dasuquin

Unlike the injectable adequan, Dasuquin and other oral joint supplements are considered nutraceuticals, or nutritional supplements, and do not require FDA approval. Cosequin contains glucosamine and chondroitin sulfate, agents proven to be effective at supporting and protecting joint cartilage.

In addition, Dasuquin contains ASU (avocado/soybean unsaponifiables) that makes the glucosamine and chondroitin sulfate more effective.

There is a Dasuquin made for cats also

NSAID’S

The non-steroidal anti-inflammatories (NSAID’S) are the most commonly used drugs in treating OA in dogs. We also use them in cats, but for a shorter duration. NSAID’s are highly effective and tend to be the drug of choice when we put your pet on actual arthritis medication. They are so effective we even use them for routine post operative pain control in dogs and cats. They have saved many a dog from long term pain, and even euthanasia.

NSAID’S work by inhibiting an enzyme in the inflammatory pathway, thereby providing analgesia (pain relief), antipyrexia (decreased fever) and reduced tissue swelling. The enzyme that is inhibited is  cyclooxygenase (abbreviated COX). This enzyme causes an inflammatory reaction in the joint fluid that surrounds the joint.

A common NSAID is Rimadyl. We use other NSAID’s in addition to this one.

Before we start your pet on NSAID’S we perform an examination and run a baseline blood sample. Every 6 months we will examine your pet and recheck the blood to look for any potential side effects. This will make sure kidney and liver function is adequate.

This pet has kidney disease, and the kidney problem needs to be addressed before we institute NSAID therapy. We would use a lower dose of the NSAID many times in a pet with kidney disease like this to make sure the NSAID is not making the kidney disease worse. 

Using NSAID’S alone is not recommended since the signs of arthritis are masked, leading to a more active dog and a quicker progression of arthritis. NSAID’S, in combination with weight loss and chondroprotective agents, provide cartilage building blocks in addition to pain relief, and may slow the progression of OA.

All NSAID’S carry a small risk of side effects, so careful observation of your pet while on one of these medications is important. If they occur, the most common side effects are vomiting and diarrhea. There might also be kidney and liver problems, and even bleeding. These side effects can be minimized by using the lowest dosage and frequency possible, giving the medication on a full stomach, and giving Pepcid AC  prior.

The best way to minimize the potential for side effects, yet still get the most out of NSAID’s, is to use the lowest effective dose of the NSAID of choice, and combine it with proper diet,  VNA and Companion Laser as additional treatments. You will learn more about these treatments below.

We do not routinely use NSAID’s in cats due to their potential to cause kidney damage. These cats do best with weight loss if they are overweight, J/D diet if they are not overweight, Dasuquin, VNA, and Companion Laser. A new NSAID for cats is called Onsior. It is approved for treatment of pain and inflammation for 3 days, so we use it routinely in our post operative cat patients.

The other primary NSAID we use in cats is called meloxicam (Metacam). It is used only for a few days due to the potential for problems with the kidneys.

VNA (also called VOM in the past)

An additional treatment modality that has yielded great success  for well over the last 20 years is called VNA. It has been a game changer for us in the treatment of arthritis in a wide variety of animals.

It is a non-invasive and non-painful way to stimulate the autonomic nervous system to help correct the problem. Through the use of VNA we can decrease the use of the above medications in almost all cases. By decreasing the use of these medications, we help your pet live a longer and healthier life, while decreasing you medication costs over the life of your pet. Click here to learn more about VNA.

This dog is getting VNA therapy for its arthritic spine

Cats respond very well to VNA treatment. They get what is called the “Feline Hyperesthesia Syndrome. In this syndrome, their lower backs are extremely sensitive, so much so that they start licking compulsively when scratched there, can bite an owner due to pain, and even go into a seizure.

Look how sensitive this cat is when scratched at its rear quarters

As we perform VNA the cat relaxes completely because the sensitivity is diminished

We use VNA in a wide variety of species. This rabbit has GI stasis, and felt much better after this treatment.

Companion Laser Therapy

In the last few years we have added a new and natural way to treat arthritis using the Therapy Laser. This modality has been used to treat people for over 30 years and has recently been approved by the FDA for use in animals. This treatment modality has been a huge boon to our geriatric pets with painful arthritis, especially when used with low dose NSAID’s and VNA.

To learn more about it please click here or on the picture below.

Acupuncture

This can also be used at any time to augment the treatment already being utilized. To learn more about how we use acupuncture follow this link.

Do you see the two acupuncture needles on this pet’s neck?

Miscellaneous Pain Medications

Galliprant

This is a prostaglandin antagonist that helps with pain and inflammation. It is used only in dogs.

Gabapentin

This seizure medication is another useful adjunct as the arthritis progresses.

Brupenorphine

Short term use can be effective for pain control.

Regenerative Medicine

What this is not doing is to generate new and healthly cartilage, as is a common misconception. What this treatment does is take a high concentration of growth factors and anti-inflammatories and bring them to an area of relatively poor tissue healing with the chance there will be a reduction on the inflammatory process.

Stem Cell Therapy- (Adipose Derived Stem Cells ( Ad-SCT ))

This promising yet unproven treatment utilizes stem cells from your own dog’s fat cells to alleviate arthritis symptoms. This means there is no chance of rejection, a major advantage of this technique.

Your dog has to be anesthetized for a short time in order to harvest the fat cells. Collection sites can be in many areas depending on your dogs conformation and fat reserves. Once the fat cells are harvested they are shipped overnight to the company that isolates the stem cells with a specialized technique. They are returned usually within 48 hours. We sedate your pet again and inject the stem cells into the affected area.

We will keep you posted as this promising therapy is given better scrutiny to make sure it has no deleterious effects in the long run and actually helps.

Platelet Rich Plasma (PRP)

This is a blood sample from your pet with a high concentration of  platelets without red blood cells (RBC’s) and some white blood cells (WBC’S). These platelets have growth factors and anti-inflammatory properties.

Rehabilitation

This can range from using wobble boards and exercise balls up to underwater treadmills. These can be beneficial, and we would send you to a veteriinary specialist to help determine if this will help in your pet’s case.

Here is the link to the Feline Musculskeletal Pain index. Please print it out and bring it in when we examine your cat.

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Liver Disease

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This page has a detailed description of this disease in dogs and cats (canine and feline). This page shows detailed information, with many links, of how we diagnose and treat liver diseases,  You will learn proper medical care with well established medical treatments, that also includes natural remedies with food and homeopathic treatments. Our pets cannot talk to us, so it is important that you understand this disease as much as possible.

The largest organ in the body is the liver, an indication of its importance in health. It is involved with almost all of the biochemical pathways that allow growth, fight disease, supply nutrients, provide energy, and aid reproduction. Liver cells, which are called hepatocytes, go through thousands of complex biochemical reactions every second in order to perform these myriad functions.

Since the liver is involved with almost all biochemical processes it is no wonder that there are many different diseases that will affect it. This page will cover some of the more important ones we see in animals. The beginning of this page will discuss liver anatomy and physiology, eventually leading to detailed explanations of the more common liver diseases we encounter. This complex organ does not lend itself to easy classification or understanding. Many of the functions of the liver overlap with other organs, and some of the liver’s functions involve complicated biochemical pathways. If this page is too complex for your needs you can go right to our summary page on liver disease.

Even though it makes for good reading, you can skip the anatomy and physiology section and go right to the section on specific diseases if that is all that interests you:

 


Terminology

It is helpful to be exposed to several medical terms that will be used later in this page:

hepatic- having to do with the liver icterus (jaundice) – yellow discoloration of skin or mucous membranes
hepatocyte- individual liver cell hypertrophy- increased size of an organ
hypoalbuminemia – low albumin polyuria- excess urinating
hypoproteinemia- low protein polydypsia- excess drinking
polyphagia- excess appetite PU/PD- polyuria and polydypsia
ascites- fluid buildup in the abdominal cavity gluconeogenesis- the manufacture of glucose
hypertension- increased blood pressure iatrogenic- caused by something a person does as opposed to happening naturally.
euglycemia- normal blood glucose (sugar) level homeostasis- normal physiology
hepatomegaly- enlarged liver septicemia- excess accumulation of bacteria and toxins in the bloodstream
hepatitis- a general term for inflammation of the liver parenchyma- the internal anatomy of an organ
encephalopathy- chemicals, like ammonia, that depress the brain laparotomy- exploratory surgery of the abdomen
anorexia- poor appetite H.E.- hepatic encephalopathy
metastatic- a tumor that has spread from elsewhere in the body microhepatica- abnormally small liver
cholestasis – excess bile accumulation in the liver

Next you will learn about Liver Anatomy

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Bladder Stones

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Stones in the urinary tract are common in dogs and cats. Even though dogs and cats do get kidney stones, it is bladder stones that cause more problems. The medical terms for bladder stones are urolithiasis or cystic calculi. We will use stone, calculi, and urolith synonymously in this page. The two most common calculi are calcium oxalate and struvite.

Stones can also occur in the kidneys, where they are called nephroliths. This page will limit its discussion to stones in the bladder.

Towards the end of the page we have a video on a surgery where we remove bladder stones with the laser.

Graphic pictures and videos on this page.

Cause

There are several factor, usually working in combination, that lead to urolith formation:

  • Mineral Crystals

    Urine that is saturated with excess amount of certain minerals is prone to form bladder stones. These minerals commonly include magnesium, phosphorous, calcium, and ammonia. Most stones consist of an organic matrix of protein surrounded by crystalline minerals.

    Diet can have a major impact here, and is one of the primary methods we use to treat and prevent uroliths.

  • Urine pH

    pH is an indicator of acidity by measuring the hydrogen ion concentration. A pH of 7 is neutral. Below 7 is acidic, above 7 is alkaline. As a general rule, dog and cats tend to have an acidic urine. Some uroliths have a propensity to form in acidic urine, while others tend to form in alkaline urine. Urine pH needs to be measure immediately upon voiding from the bladder for it to be accurate.

  • Bacteria

    Some uroliths form due to the presence of bacteria in the urine, so control of these bacteria is important. Bacteria are diagnosed by culturing the urine during a sterile urinalysis, or by culturing the inside of a stone after surgical removal. Normal urine is sterile, so any bacteria cultured from the urine is abnormal. When bacteria are cultured a pet has a urinary tract infection (UTI) and needs antibiotics. Common bacteria in UTI’s include E. coli, Staph. spp., and Proteus.

    If any bacteria are cultured in the urine our laboratory will test numerous antibiotics to determine which are the best ones to eliminate the bacteria. This is called sensitivity testing. We also do a test called MIC (Minimum Inhibitory Concentration) to let us know the best antibiotic to use and the best dose of that antibiotic.

  • Diseases

    Liver shunts are an abnormality of blood flow to the liver. Blood that would normally flow through the liver now bypasses the liver. One of the many consequences of this disease, called Portosystemic shunts (PSS), is the formation of ammonium urate bladder stones.

  • Medications

    Medications can predispose pets to forming bladder stones. Sometimes they do this by increasing the calcium level in the urine. Medications that increase or decrease the pH of the urine can also set the stage for stone formation. Some medications can actually cause formation of stones when used for long periods of time. The following list includes some of these medications:

    • Lasix
    • Cortisone
    • Ascorbic Acid (Vitamin C)
    • Sulfa medications
    • Tetracycline’s

Predisposing causes of bladder stones include pets that are not drinking enough or are not allowed to urinate frequently. Bacteria and stone forming chemicals stagnate in the urinary bladder and increase the chance of a stone forming. Mechanical flushing of the bladder, in the form of normal and frequent urination, will prevent this.

Always make sure your pet has access to fresh water, changed several times per day, and the ability to urinate frequently. As a matter of fact, if you feed dry food you should be giving more than one cup of water per cup of dry food. An easy way to get around this important requirement for water is not to feed dry food at all. Your pet’s urine should be clear, with no odor or color, and your pet should urinate every few hours. Sometimes these common sense suggestions are so obvious that we tend to forget about their importance.

Typical symptoms of bladder stones:

  • Straining to urinate (stranguria)
  • Blood in the urine (hematuria)
  • Urinating small amounts frequently (pollakiuria)
  • Often times there are no symptoms at all, and the problem is discovered on routine abdominal palpation or radiography.

There might also be excess urination (polyuria), pain in the rear quarters, reluctance to jump or play, or even lethargy and a poor appetite. Some pets can have bladder stones without any apparent symptoms at all!

The bladder stones can pass out of the bladder and lodge in the urethra, especially in male dogs due to the smaller diameter of their urethra. In some cases they can block the flow of urine, which is a medical emergency. This can cause problems with the kidneys, leading to the buildup of toxic waste products. Common areas for these urethral obstructions are the ischial arch near the pelvis and further down the urethra at the os penis. Both of these areas have small diameter urethras that do not expand to allow passage of a stone. You will learn more about this later.


Diagnostic Tests

  • Urinalysis

    A urinalysis is crucial in making a correct diagnosis. The pH of the urine, and the presence of bacteria or crystals all provide valuable information.

    Abnormalities that can be found in the urine in a pet with a urolith include:

    • Blood
    • Increased white blood cells
    • Increased protein
    • Crystals
    • Bacteria
    • Low or high pH

    The presence of crystals (crystalluria) is a sign that a urolith is possible, and usually warrants further investigation. At this point we might take radiographs, do an ultrasound, do a urine culture, or recheck it in the next few weeks or months.

    This is an example of a normal cat urinalysis. The pH is neutral, there are a few white blood cells (WBC’s) and red blood cells (RBC’s),  with calcium carbonate crystals, and no bacteria.

  • Urine Culture

    Bacteria are implicated in many cases of urolithiasis. Culturing the urine will let us know what bacteria, if any, are involved, and which antibiotic(s) will be effective. In addition to serving as a nidus for urolithiasis, these bacteria can ascend from the bladder into the kidneys, causing a pyelonephritis.

    This is a culture & sensitivity report we received from our lab. We sent them a sample of urine directly from the bladder, and asked them to let us know if there are bacteria in the normally sterile urine. The organism they cultured is E. coli, a common bacteria in both animals and humanoids. This bacteria is pathogenic in the bladder, and is causing a urinary tract infection. The lab tests numerous antibiotics and determines which antibiotic(s) E. coli is sensitive to.

As you can see from this culture, E. coli is resistant (R) to numerous antibiotics


After we have determined that bacteria are part of the problem our lab provides us with information on how effective antibiotics will be at the level of the bladder.

Radiography

One of the best methods to make a diagnosis of uroliths is radiography. Many stones are radiopaque, which means they show up vividly on an x-ray. Radiopaque stones include struvite and calcium oxalate. Some stones are radioulucent, and depending on size and number, do not show up on a regular x-ray. These stones are diagnosed by injecting air, dye, or a combination of both, into the bladder to outline any suspected stone. Ultrasound is a great way to detect these stones. Radiolucent stones include ammonium urate.

 

This is the side view of a dog with a very large radiopaque stone in its urinary bladder

 

This is a picture of the stone that was in the x-ray above

 

Other stones aren’t always this smooth. Even though this stone is small, the roughened edges were probably painful in this dogs bladder.

This dog has stones in the bladder and in the urethra as marked by the two arrows on the right. The arrow on the left is showing an enlarged liver lobe.

Click on any of these photos to make them larger

Did you notice the stones in the kidney also?

Radiographic appearance right after surgery to remove the stones in the urinary bladder

This radiograph is from a rabbit that has calcium carbonate sludge in its bladder. You can learn more about this and how we treat it from this link.

Ultrasound

Ultrasound is a very precise method to diagnose stones in the urinary bladder. It is particularly helpful for radiolucent stones and anatomical defects of the bladder wall.

OLYMPUS DIGITAL CAMERA

In this picture the bladder stone is demarcated by the two crosses.

This cat had blood in the urine and a urinary tract infection. There were no calculi in the bladder. Unfortunately there was a malignant cancer in the bladder called a transitional cell carcinoma. Surgery was performed to removed the cancerous portion of the bladder. What we originally thought was a urinary tract infection, with possible cystic calculi, turned out to be a more serious problem. This ultrasound finding, and subsequent treatment, emphasizes the importance of thorough diagnostics.

Bagel Freer Nichole bladder surgery TCC? Linda Larsen

Without the ultrasound we would have not found this tumor soon enough to treat.

 


Composition

We send our stones to the Minnesota Urolith Center at the Univ of Minnesota. They have more experience than any other place in the world regarding animal bladder stones.

minnurolith4

Bladder stones are compliclated, and made of many layers and compounds

minnurolith2

They give us a detailed report on the stone

minnurolith3

This is the protocol for a calcium oxalate stone to prevent recurrence

There are many different types of bladder stones. Some of the most common ones include:

    • Struvite

      This urolith is diagnosed in almost half the cases of bladder stones. It is also called MAP (Magnesium-ammonium-Phosphate), or triple phosphate. Struvite uroliths come in many different shapes and sizes, are radiodense, and form in an alkaline urine.

      It is the predominant stone type in female dogs of all breeds except Dalmatians. This is because of the high association of struvite crystals with urinary tract infections, which are more common in female dogs. If a female dog gets a bladder stone, 80% of the time it is struvite because of this association. Dogs under a year of age, no matter what  sex, get struvite as the most common bladder stone for this same reason. Miniature Schnauzers are the most commonly affected breed, along with bichon frise, cocker spaniels, and miniature poodles.

      Canine  urine is commonly supersaturated with struvite crystals due to the high protein and mineral content of current diets. This excess of these crystals in the urine, stored in the urinary bladder, combines with bacteria to set the stage from the formation of bladder stones (uroliths). Bacteria that are commonly implicated include Staphlycoccus, Enterococcus, and Mycoplasma.  These bacteria increase the amount of organic debris available for crystallization.

      These bacteria also produce urease as a by product of their metabolism. They  split the urea in urine into ammonia and carbon dioxide. As this ammonia is broken down it changes the pH of the urine from its usual acid (pH less than 7) to alkaline (PH > than 7). High urine ammonia concentrations in the urinary bladder can damage the glycosaminoglycans that help prevent the bacteria from adhering to the bladder mucosa (interior lining of the bladder). When we treat for this disease we address these issues.

      What does all of this mean?

Excess struvite crystals in the urine  set the stage for the formation of the urolith.

Urinary Tract Infection (UTI)- some bacteria produce a byproduct called urease. Urease will increase the pH of the urine and promote ammonium in the urine.

The formation of an alkaline (pH greater that 7.0) urine from the diet, or from urease producing bacteria, will cause the struvite crystals to precipitate out of solution and begin the formation of a urolith.

Urine that stays in the bladder longer than usual gives the struvite crystals further opportunity to precipitate out of solution and form a urolith.

    • Cats commonly form struvite bladder stones in the absence of a urinary tract infection. This is probably because cat urine is more concentrated (higher specific gravity) than dogs, so the urine is more saturated (we call this supersaturation) with magnesium, ammonium, and phosphate. This is especially true when the urine pH is highly alkaline, which can occur with the use of some drugs, in certain diets, and when the tubules of the kidney are diseases. If there is a bacteria involved it is usually Staphlycoccus.

Calcium Oxalate

This is the second most prevalent type of urolith after struvite, making up around 30-50% of the uroliths we diagnose, especially in male dogs of all species, except Dalmatians. They come in two versions; the monohydrate and the dihydrate. Sometimes the two are found together, sometimes they are found with other uroliths like calcium phosphate, struvite, or ammonia irate. They show up well on a radiograph. They form in an acidic or neutral urine (pH is 7 or just slightly less). Recurrence is common, so diligence on your part is needed to prevent recurrence.
Feeding an older pet with Kidney problems a food like Hills Prescription Diet K/D may slow or prevent further growth.
If this stone is small and not causing any apparent problem it can be monitored. Some pets will have high calcium (hypercalcemia) in the bloodstream.

Several predisposing factors work together to increase the chance of this urolith forming:

Increased calcium in the bloodstream (hypercalcemia)

Increased calcium in the urine (hypercalciuria) with no hypercalcemia

Concurrent Cushing’s disease

Use of cortisone for skin allergies or Addison’s (hypoadrenocorticism) disease.

Feline
These tend to occur in neutered middle aged cats and older cats, especially Burmese, Himalayan, and Persian breeds. One of the predisposing conditions might be an increased calcium level in the bloodstream. These uroliths tend to form in an acidic urine.
Canine

This is a problem most commonly in older male dogs. It is suspected that there is a correlation with hormone changes that occur as a pet ages. Several breeds are prone:

Miniature Schnauzer

Lhasa apso

Yorkshire terrier

Bichon Frise

Shih Tzu

Miniature poodle

Urate and Ammonium Urate

This is a common urolith found in Dalmatians around middle age, with males affected much more often than females. This is because they metabolize protein differently in the liver, with the end result being uric acid buildup in the urine. In addition to their high prevalence in Dalmatians, they are found in Bulldogs and Yorkshire terriers.
There does not seem to be a connection with a urinary tract infection, and they tend to form in an acidic urine.
Urate stones are radiolucent. If they get large or covered with other minerals they might become radiopaque. Urate calculi tend to be small and occur as several stones. These stones usually form in the bladder, and when passed through the urethra, can become lodged.

Ammonium urate uroliths are sometimes formed in pets with PSS (liver disease) due to improper metabolism of ammonia to urea. This will cause excess uric acid levels in the bloodstream. The kidneys filter out this excess uric acid in the production of urine, thus increasing the level of uric acid in the bladder. The excess ammonia that is in the bloodstream from the liver problem also builds up in the urine in the bladder. These two compounds combine to form the ammonium urate bladder stone.
Dogs with ammonium urate bladder stones might have ammonium urate crystals in their urine and a low specific gravity (dilute urine). These stones might not be seen on a radiograph because they are radiolucent. This same radiograph might also show a small liver, an indication of PSS. This small liver is due to the diverted blood flow to the liver. Dogs with PSS will commonly have abnormalities in the blood sample to give us further clues.

Compound Uroliths

Most bladder stones are caused predominantly by one type of mineral. The more common ones have been described above. In a small percent of cases, the bladder stone is caused by a combination of minerals in similar quantities. These stones are called mixed uroliths. Some bladder stones consist of a core mineral surrounded by a lesser amount of a different mineral in a different layer. These are called compound uroliths. Why some minerals form mixed uroliths and others form compound uroliths is not understood.
Compound uroliths form when the factors that predispose to one type of stone formation have now changed to factors that favor a different type of stone formation. If a struvite stone is treated with antibiotics and urinary acidifiers the problem tends to resolve. The change in urine pH might promote excess calcium in the urine, resulting in a shell of calcium oxalate formation around the core struvite stone. The opposite can occur also- a struvite stone can form over a calcium oxalate stone.
In general, these stones are removed surgically and an effort is made to medically prevent the mineral that is at the core of the stone.

Miscellaneous Uroliths

There are other uroliths that occur, although they are relatively uncommon. They include cystine, silica, calcium phosphate, and miscellaneous minerals.


Treatment

Struvite

Most cases of struvite are treated surgically. The procedure is explained below.

Struvite bladder stones can also be be treated medically with a food called Hills S/D. The mechanism involves creating a urine that is undersaturated with the crystals that caused the struvite urolith to form in the first place. This undersaturation literally cause the urolith to dissolve in the urine, and then get urinated out. It is a slow and gradual process, although most pets get relief from straining and blood in the urine soon after starting this diet.

S/D has several modifications in its ingredients to set up this undersaturated urine. Its reduced in protein, so there is less ammonia buildup in the bladder from bacteria. Magnesium and phosphorous are restricted also. With less contents of the minerals that form the struvite urolith (magnesium, ammonia, and phosphorous- MAP) the urolith starts dissolving.

S/D also has an increased amount of salt (sodium chloride). This promotes drinking and urination and literally helps flush the struvite crystals out of the bladder. It also changes the pH to a more acidic state, which further makes the struvite stone dissolve.

The rate of dissolution is proportional to the surface area of the stone expose to this now undersaturated urine and the control of the urinary tract infection in dogs.  Feline struvite stones tend to dissolve faster than canine because bacteria are not implicated.

We can measure the size of a stone with our digital x-ray to make sure it is getting smaller early in the process of dissolving it

S/D must be the only food fed for it to work. We can monitor whether or not an owner is doing this by looking at the pH of the urine along with the specific gravity of the urine. also, the BUN (blood urea nitrogen) of a pet on S/D should be lower than normal.

We have clues from other diagnostic tests to help decide if a urolith found in the urinary bladder on a radiograph is truly struvite. The urinalysis gives us an idea of the composition of the urolith by looking at the crystals in the sediment. The pH of the urine will be alkaline. Also, the presence of bacteria on a culture in a breed that is prone to struvite uroliths is also a strong indication.

If bacteria are found on a urine culture in dogs then antibiotics must be used simultaneously while a pet is on S/D. It must be the correct antibiotic, so the importance of the urine culture is obvious. Both S/D and antibiotics are used for one month after the stone is no longer visible on a radiograph. If there is a persistent urinary tract infection we might use a urease inhibitor called acetohydroxamic acid. Urinary acidifiers are usually not used.

If the urolith is still present after 2 months of S/D and antibiotics, then surgery should be performed. Most pets need to be fed S/D for 4-6 months for complete resolution. It should be fed for an addition 30 days after there is no longer any stone based on a radiograph.

S/D is restricted in protein, so it is not a complete diet for long term use in dogs. It also should not be used pregnant dogs, lactating dogs, ground dogs, and after surgery due to this protein restriction. While on S/D your dog’s blood should be monitored to ensure there are no side effects of the restricted protein.

Due to the high salt (sodium chloride) it should not be used in dogs with congestive heart failure and hypertension.

S/D diet tends to work faster in cats because bacteria are not usually involved. S/D should also be fed for 30 days after there is no more evidence of a stone in the bladder when radiographed. Feline S/D is not protein restricted, so it can be used for the rest of your cat’s life.

Calcium Oxalate

The only treatment for these uroliths is surgical removal. This is the easy part, its preventing their recurrence that is difficult. The protocol in how to do this was shown earlier.

Urate

If there is no PSS these uroliths can sometimes be handled medically also. A food called Hills U/D should be used. It is low in purines and has restricted protein. A medication called allopurinol is given which helps minimize the amount of uric acid produced in the urine. Potassium citrate is also used to make the urine less acidic, although this might occur with the use of U/D alone. Adding salt to the diet or mixing water with the food will also promote urination of the urate crystals. Recurrence is common, so this diet needs to be used for the life of your pet, especially in Dalmatians. We will talk more about this later in the prevention section.

Surgical Treatment

Many bladder stones are treated surgically.

We usually use the laser to make an incision in the bladder. Here is a link to how we do surgery at our hospital.

Many of these bladders are thickened from chronic irritation, which means they have an extensive blood supply. You will see that in the following photos. When you watch the laser surgery on one of these thickened bladders notice the blood supply and how little bleeding there is.

Surgery-Monitor

We keep a close tab on important physiologic parameters for all of our surgeries. Monitors like this give us an early warning of an impending problem

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Once our surgeon has scrubbed up and is  in sterile gown, gloves, and mask, the surgery begins

The surgical removal of a stone in the urinary bladder is called a cystotomy. It involves making an incision into the abdomen, exteriorizing the urinary bladder, removing the stone(s), and resuturing the bladder. When we make the incision into the bladder the laser is used in almost all cases because of dramatically less bleeding during the surgery and dramatically less inflammation after we remove the stone and suture the bladder.  For those of us that have had surgery we know the importance of minimizing post operative pain. Your pet will be happy we used the laser!

The laser is a precise machine customized for each surgery. Watch how we set it up and how it checks its circuits and calibrates itself in this video

Laser-cystotomy

The initial incision of this thickened bladder with the laser. Notice the lack of bleeding, even though this is the second time these stones have been removed. Click on this link to see a short movie of this incision

 

Laser-cystotomystone

The actual calcium oxalate stone (there were 5 of them overall) removed from this bladder

A movie of this stone removal

 

The bladder is not the only location for stones to occur. This dog has 2 in its urethra at the tips of the black arrows.

 

A close-up view give better visualization. This is an example of stones that are lodged at the ischial arch, described previously in the symptoms section.

We passed a urinary catheter under anesthesia and started flushing the stones towards the bladder. Once they are in the bladder they can be removed via cystotomy.

In this view you can see how the stones have moved slightly from the flushing. It took 8 more flushings to move them all the way into the bladder.

This is a picture of the bladder during the actual flushing. The bladder has an incision in it because this dog also had a calculi in its bladder, which has already been removed. It takes significant force to move the stones from the urethra back into the bladder.

You can see the saline solution flowing out of the bladder towards the left (arrow)

How we suture the bladder after the stones are removed

These are the three stones that were removed- one was in the bladder and two were in the urethra

 

This is the stone analysis of the above uroliths verifying that they are calcium oxalate stones

The center of the stone was cultured. The culture yielded an organism called nonhemolytic coagulase negative Staph. This is the same bacteria that can be found on your skin.

This bacteria is sensitive (S) to 5 of the antibiotics on the list.

There is another common area for stones to lodge in the urethra of male dogs. Towards the end of the urethra male dogs have a boney structure that surrounds the urethra. This structure is called the os penis. In this area the urethra cannot expand to let a stone pass, hence stones commonly lodge here. This can prevent urination, with potentially serious consequences for the kidneys.

The white line outlines the urethra as it passes from the bladder, goes over the ischial arch and through the os penis. The arrow points to the beginning of the os penis, the area where a stone would lodge.

buddy1

The arrow points to a stone at the os penis

buddy2

It was flushed back into the bladder with a catheter. Here it is part way back.

buddy3

After a few more flushings it was pushed back into the urinary bladder, along with the other stones that are already in the bladder. It was removed doing a routine cystotomy.

buddy5

After the large stones we removed the smaller ones, which are hard to visualize in the bladder, are flushed out. This radiograph after surgery shows there are no more stones in the bladder.

buddy7

This is the stone that was originally stuck behind the os penis, and flushed back into the bladder. It is only a few millimeters in size, but with its rough appearance, is probably not very comfortable to say the least.

There are several sequelae to these stones in the urethra. If the urinary bladder has been distended long enough it loses its ability to contract and urinate properly. Nerve damage in the spinal cord can also cause this. The end result is an animal where the urine builds up in the bladder until the point it passively overflows and they dribble.  These animals are predisposed to chronic infections, not to mention the pain and discomfort of a distended urinary bladder.

This radiograph shows a dog with a seriously distended urinary bladder (UB). Its the large white area in the middle of the radiograph. The dark area to the left and slightly overlapping the front of the urinary bladder is the stomach (S) filled with food.

Prevention

Medical dissolution or surgical removal of the bladder stone is the first step in the process. The next, and just as important step, is the prevention of the stone’s recurrence. Some of these stones will require a diet change only, while others might require long term medication. Some breeds are predisposed to forming stones in spite of what we do to prevent them. Our doctors will set up a specific protocol for your pet based on the breed and type of stone removed.

Long term follow up is important. Your pet will have to return periodically to recheck a urinalysis, culture the urine for bacteria, and x-ray the bladder. Many stones recur because owners forget the importance of long term prevention.

At all times make sure your pet has access to fresh water and the ability to go to the bathroom. This treatment alone will go a long way to prevent recurrence. Giving your pet food that has more moisture will increase the flow of water through the urinary system and minimize crystal formation in the bladder. As a general rule, we do not recommend adding salt (sodium chloride) to the food to get your pet to drink more water because it might promote calcium formation in the urine, thus setting the stage for a stone to form. Your doctor will let you know if this applies in your case.

Struvite

Pets that have struvite urolithiasis, whether treated surgically or medically, have a chance of recurrence if not monitored carefully. If the urine is alkaline on a urinalysis it should be cultured to check for bacteria. Antibiotics are indicated if the culture is positive. If the pH stays alkaline in spite of antibiotic therapy, then Hills C/D should be used. It will help maintain an acidic urine, and has some mild restrictions in protein and minerals. As a general rule, we recommend C/D for all pets that have had struvite crystals. It can be used on a long term basis, and is helpful in preventing FLUTD in cats. S/D can also be used long term in cats.

If your dog gets recurring urinary tract infections, thus predisposing it to a struvite bladder stone, it is important to examine it for abnormal anatomy of the vulva, for obesity, and problems with the urethral sphincter.

Calcium Oxalate

Recurrence rates with this urolith are high, so a long term plan and commitment to sticking with it are important.

Baseline data consisting or radiographs, urinalysis, urine culture, and blood panel needs to be obtained. Particular attention is paid to the blood calcium level.

A diet with reduced quantities of protein, calcium, and sodium, that also does not make an acidic urine, is the ideal diet to feed. Too much of a reduction in these nutrients can be detrimental, so no supplements should be added. The primary diet in the cat that accomplishes this ideal is Hills Prescription Diet K/D. In dogs, K/D, W/D, and U/D are used. The use of U/D might preclude the use of potassium citrate as long as there are not calcium oxalate crystals in the urine and the pH is alkaline. There is a C/D that treats calcium oxalate uroliths in cats.

Certain foods that are high in oxalates or calcium, or foods that increase calcium levels, must be avoided. They include high protein foods, spinach, rhubarb, parsley, milk products, and table salt.

When we diagnose a calcium oxalate stone we will check the calcium level in the bloodstream to make sure it is not abnormally high. This normal calcium level was from the dog above that had the surgery to remove the calcium oxalate stones from its bladder and urethra.

Vitamin C and D, along with drugs that make the urine more acidic, should not be added to the diet. Cortisone also should be used cautiously because it increases the calcium level in the urine.

Potassium citrate will inhibit calcium oxalate crystal formation and keep the pH of the urine in the ideal range. We will use this if U/D does not keep the urine alkaline.

After surgery your pet should return in 2 weeks for a urinalysis. If there are calcium oxalate crystals in the urine we will add potassium citrate as per above. If there are no crystals we will not need to do a recheck for 3 months. At this 3 month recheck of the urine we will also re-radiograph the bladder and check a blood panel noting the calcium level.

Two weeks after surgery this is the urine sample of the dog with the above stones. This is what we want to see- no crystals, no bacteria, and an alkaline pH.

If calcium oxalate crystals persist in the urine 2 weeks after adding potassium citrate, we will add Vitamin B6 to the diet. If the B6 does not eliminate the crystals, we will use a drug called hydrochlorothiazide. Use of this drug requires close monitoring of the potassium level and the calcium level in the bloodstream.

A urinalysis should be performed every 3-6 months to look for crystals in the urine and monitor the pH. A urine culture should also be performed at this time to decide if antibiotics are needed.

Ammonium Urate and Urate – Medical care for Dalmatians after surgery includes:

  1. Increasing water consumption so the specific gravity of the urine is near 1.018. adding water to dry food, feeding more canned food, and adding encapsulated light salt (KCl) all will help.
  2. Feeding a diet low in purines. Diets low in purines include the Hills Prescription Diets K/D or U/D dry and U/D canned.
  3. Increasing the pH of the urine to 7.0-7.5. The above diets might accomplish this pH. If not, adding oral potassium citrate to the diet will help.
  4. Controlling urinary tract infections, if any, by performing urine culture and sensitivity tests every 3-6 months, and using antibiotics on a long term basis if needed.
  5. Adding allopurinol to the diet to prevent the conversion of purine to uric acid.This therapy needs to be followed diligently for the life of your Dalmatian.

Medical care for cats and non-Dalmatian dogs after surgery is similar. Most of these uroliths are caused by a PSS, thus surgery to correct the liver problem will help prevent the recurrence of these stones in the bladder. In some PSS’s the liver problem cannot be completely resolved, adding to the risk of formation of these bladder stones in the future. Long term therapy is similar to Dalmatians:

  1. Increasing water consumption so the specific gravity of the urine is near 1.018 for dogs and 1.025 for cats. adding water to dry food, feeding more canned food, and adding encapsulated light salt (KCl) all will help.
  2. Feeding a diet low in purines for dogs. Diets low in purines include the Hills Prescription Diets K/D or U/D dry and U/D canned. For cats feed diets that do not acidify the urine, which unfortunately, many do to prevent FLUTD.
  3. Increasing the pH of the urine to 7.0-7.5. The above diets might accomplish this pH. If not, adding oral potassium citrate to the diet will help.
  4. Controlling urinary tract infections by performing urine culture and sensitivity tests every 3-6 months, and using antibiotics on a long term basis if needed.

Compound Uroliths

Since these stones have a combination of minerals they present a dilemma in their prevention. In general, it is recommended that an effort is made to prevent the mineral that forms the core of the stone.

The majority of compound stones are struvite core with a calcium phosphate outer core.

An additonal treatment modality, used especially after we remove the urolithiasis is VNA. It is a non-invasive and non-painful way to stimulate the nervous system to increase blood flow to the kidneys. This will increase urine output, making it more difficult for the stone to start all over again. It is a highly effective way to help prevent the problem from recurring.


Dietary Information

Pet food manufacturers have dramatically increased their sophistication in treating bladder problems in dogs and cats. It is because of these advances that we are able to treat and prevent many of these uroliths medically. Unfortunately, a change in food to treat struvite uroliths predisposes a pet to calcium oxalate uroliths, and vice versa. One of the ways we have gotten around this is to produce a food in cats, called C/D multicare, that prevents both. There is even a C/D stress diet for cats in multiple cat households, or those prone to stress.

In order to remedy this situation it is important to make a correct diagnosis so that the proper type of food can be used. To ensure that you are not setting up an environment for a different urolith to form in the future, the urine should be monitored every 3 months.

Another remedy is to use combined diets that have been formulated to take care of both of these calculi simultaneously. This might help if compound uroliths are present.

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Sarcoptic Mange (Scabies)

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Sarcoptic mange (cats get a version called notoedric mange ), commonly know as scabies, is caused by an external parasite called Sarcoptes scabei  that burrows deep into the skin. It commonly occurs in dogs, not so commonly in cats, unless is it notoedric mange), also occurs in foxes, ferrets, rabbits, sheep, goats, cattle, pigs and guinea pigs.

It is contagious to other pets and occurs in many different animals. It causes intense itchiness, especially affecting the ear margins, elbows, and face. People can pick up this disease from their pet and show symptoms of itching, but it goes away by itself in many cases and usually  does not require treatment in most cases (always check with your doctor).

It is important to note that the diagnosis of this skin condition, like most skin conditions, cannot be made just by looking at a pet. Diagnostic tests are mandatory to arrive at a correct diagnosis and achieve a satisfactory outcome to therapy. Stating that an animal looks “mangey” is not the same thing as making a positive diagnosis of mange. Pets that have Ringworm , Demodex. and allergies can look like they have Sarcoptic mange.

 Life Cycle

This ectoparasite spends it life cycle of 14-21 days entirely on the host it has infected.  Overcrowded conditions increase risk for transmission. Stress from many sources can also be a factor.

History

The following history for an itching pet with sarcoptes usually involves:

  • Severe itching that is non-seasonal
  • Recently adopted or boarded pet
  • Multiple pets in the house
  • Humans in the same house that are itching with red lesions on their skin.

 Symptoms

In dogs most of the symptoms involve intense itching at the ear margins, elbows, hocks and abdomen. Less common areas of itching can include the face and feet. This itching will inflame the skin and cause scabs, with a secondary bacterial infection (pyoderma) occurring due to the trauma. Some pets will shake their ears excessively and cause an aural hematoma (swollen ear). These symptoms can mimic those of other skin conditions, so the rules of the diagnostic process should be carefully adhered to.

Other symptoms that might be present sometimes include:

  • Lethargy and depression
  • Lack of appetite
  • Weight loss

Cat mange (notoedres cati)

In cats, sarcoptic mange is caused by a mite called notoedres cati, a microscopic ectoparasite that burrows in to the skin. It is not as itchy, and occurs more often on the face, ears, paws, and tail.

This is a highly magnified view of notoedres cati as it appears under the microscope

This cat has scabies, but you can’t say that for sure just by looking at it

The top of his head shows how irritating the problem is, especially at the ears

Diagnosis

The primary way to diagnose sarcoptic mange is to do a skin scraping where the patches of alopecia occur. Finding these mites, their eggs, or their feces,  under the microscope can be very difficult in this disease. a pet that has the symptoms of Sarcoptic mange and is negative on skin scrapings for the parasite can still have the disease. In these cases we commonly treat for the disease anyway, because the treatment is highly effective.

In rare cases we will do a skin biopsy, which is a great way to rule out other diseases that have similar symptoms.

Other diseases in dogs that mimic scabies include:

  • Folliculitis
  • Malassezia (fungus)
  • Allergies
  • Contact dermatitis
  • Cancer
  • Pemphigus (immune system disease)

Diseases in cats that mimic scabies include:

  • Demodectic mange
  • Otodectic mange
  • Cheyletellia
  • Herpes dermatitis
  • Allergies

Treatment

The usual treatment for Sarcoptic mange is a drug called Ivermectin. It is an injection given weekly for up to 6 weeks. Most pets decrease their scratching rapidly after the first injection. Some dogs, particularly Collies, Shetland Sheepdogs, and Old English Sheepdogs, do not tolerate the medication well. In these pets we use a dip called Lyme Sulfur that is also very effective.

The disadvantage to the dip is the odor it causes and the staining of white coated animals. All pets in a household should be treated regardless of whether they are showing symptoms or not. Pets that have secondary skin infections from the trauma might also be put on antibiotics. Other common treatments include Revolution (selamectin) topical.

Other pets in the same household are commonly treated if they are in close contact. Treating the environment is usually not needed if all pets in the house are treated.

Some pets itch more in the first few days of treatment due to dying mites. These pets can be put on low dose cortisone for a few days in a reducing dose to get over this phase.

This dog has scabies

This is a picture from the dog above 7 days after its first Ivermectin injection

Prevention

Good nutrition and plenty of play and exercise are always important to maintain the proper balance to fight off disease. All pets in a household that has a pet diagnosed with this disease should also be treated.

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Seizures (Epilepsy)

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One of the most disturbing things to witness in an animal is a seizure, the most common neurologic problem we see in our hospital. It can traumatize the person witnessing it, and always seems to go on forever. Unfortunately, it is not uncommon for animals to have seizures, particularly dogs. Fortunately, the overwhelming majority of seizures are not life threatening, and most dogs can live a relatively normal life. Cats and other species also get seizures, but not as frequently as dogs.

This page will give you a complete explanation as to the cause of these traumatic episodes, and how we diagnose and treat them. The overwhelming majority of dogs that are seizuring have epilepsy, so we will emphasize this disorder when discussing treatment.

Here are some medical terms we will be using:

neuron- nerve cell ictus- an actual seizure
idiopathic- unknown cause postictus- period immediately after a seizure
hypoglycemia- low blood glucose (sugar) status epilepticus- continuous or clusters of seizures
hypocalcemia- low blood calcium level epilepsy- brain disorder characterized by seizures
aura- initial manifestation of a seizure EEG- electroencephalogram
syncope- a heart problem that mimics a seizure Depression- not as alert as usual
Dementia- dull or emotionless Stupor- semi conscious, asleep often, hard to arouse
Coma- Unconscious, unable to arouse at all CSF (cerebrospinal fluid)- normal fluid in the brain and spinal cord

Normal Anatomy & Physiology

The profound complexity of the brain precludes us from going into significant detail regarding anatomy and physiology. You would need to be a neuroanatomist to even begin to understand its basics. The basic unit of the brain is called a neuron, which is a specialized nerve cell. Some of these nerve cells process information, others cause a reaction. For example, your eyes, which are an extension of your brain, process images. Other neurons cause the muscles in your eyes to move in response to movement.

In all cases, there are millions upon millions of neurons in the brain, all with complex connections to each other. It is these connections that leads to the complexity and the sophistication of the mammalian brain. Unfortunately, when a neuron has a problem, these connections can let this problem spread elsewhere. If an individual neuron has is a seizure, the seizure activity in this one neuron can easily and instantaneously spread to other neurons, leading eventually to a generalized seizure.

As a rough comparison, the mammoth power failure that occurred in the Northeast U.S. in august of 2003 shows how a small problem in one area can rapidly spread to other areas. Multiply all those electrical lines and power stations with their connections by a million times, and you start approaching what occurs every second in the mammalian brain. It is beyond human comprehension to understand the complexity of all of these connections.

Pathophysiology

Seizures (fits, convulsions) are caused by abnormal activity in the brain cells, particularly in the frontal and temporal lobes of the cerebral cortex. When a neurons fires off in a seizure, it sets off a chain reaction in other neurons, and the seizure spreads. If this chain reaction stays within a specific location, a partial seizure might occur. If it spreads to occur on both sides of the cerebral cortex, a generalized seizure, the most common type of seizure, might occur.

Characteristics

  • Aura

    Behavior just prior to a seizure. Typical behaviors include panting, pacing, barking, and restlessness. Ranges from several minutes to several hours prior to the actual seizure.

  • Ictus

    The actual seizure, characterized by involuntary muscle tone and movement. Lasts from seconds to minutes, although it seems like hours when you are observing it.

  • Postictus

    Period immediately after seizure, characterized by disorientation, unusual behavior, appetite change, or weakness. It can last up to several days.

Classification

  • Generalized

    This is the most common seizure encountered in dogs and cats. Nerve cells on each side of the cerebral cortex start discharging, causing all parts of the body to be affected. Even though the original source of the seizure is usually only a small number of neurons on one side of the cerebral cortex, the discharge of these neurons causes other neurons to discharge also, eventually causing the seizure to be generalized.

  • Partial (focal)

    This seizure also starts as a small number of neurons, yet in this case it does not spread far beyond these initial neurons. Symptoms that are seen depend on which neurons are discharging. It can affect motor areas, causing involuntary movement, or it can affect areas of the brain involved with behavior, causing intermittent behavioral changes. Eventually this type of seizure can progress to a generalized seizure.

This movie is typical of a pet having a partial seizure.
Double Click Here to view the movie

Cause

Idiopathic (epilepsy, primary, genetic, true, inherited)

The word “idiopathic” means that the cause is unknown. It is also known as epilepsy in humanoids. It is a diagnosis of exclusion- if all the other causes of seizure are eliminated, then this is the cause. This is the most common type of seizure, and occurs in up to 2% of all dogs, relatively rare in cats. Any dog breed can be affected, with the larger breeds having more severe seizures. In general, we see it more often in purebred animals. The more common breeds are:

  • Alaskan Malamutes
  • Cocker and Springer spaniels
  • Beagles
  • Collies
  • Boxers
  • Dachshunds
  • Dalmations
  • German Shepherds
  • Golden and Labrador retrievers
  • Irish Setters
  • Mastiffs
  • Schnauzers
  • Poodles
  • Saint Bernards
  • Siberian Huskies
  • Vizslas
  • Australian Shepherd
  • Border Collie

In the large breeds seizures tend to be more severe. In the Border Collie and Australian Shepherd there is a severe genetic epilepsy present, and these dogs need to be started on seizure medication when seizures first start.

Secondary

Secondary seizures causing epilepsy occur when there is a structural abnormality in the brain.

Hydrocephalus

This disorder, sometimes know by its more common name of “water on the brain”, occurs in small breed dogs and sometimes cats. It is the excessive accumulation of cerebrospinal fluid (CSF) in the brain. The pressure from the fluid causes the seizures. It is not a problem that is easily corrected, and usually requires lifetime medication. Surgery can be used in select cases, but is not always effective. Pets with severe symptoms early in life have a guarded prognosis.

Common dog breeds that get hydrocephalus:

  • Chihuahua
  • Yorkshire Terriers
  • Maltese
  • Pomeranian
  • Lhasa apso
  • Toy Poodle
  • Pug
  • Pekingese
  • Boston Terrier

The most common symptom with this disorder is behavioral. If seizures occur, they start early in life.

Brain Tumor

We tend to encounter brain tumors in middle aged and older pets. Some arise directly from brain tissue, others spread to the brain via the bloodstream (since the brain has an extensive blood supply). Strangely enough, its not the neurons (brain cells) that become cancerous, it is the cells supporting the neurons, called glial cells, that cause the problem.

Tumors that arise directly from the brain include:

  • Astrocytoma
  • Oligodendroglioma

Symptoms of brain tumor depend on exactly where in the brain they arise, and how fast they grow.

Brain tumors are best diagnosed with an MRI.

Most brain tumors are treated medically- surgery is used only on rare occasion. The progress is poor if your pet has a brain tumor.

Can you see the large tumor in this brain?

Trauma

Pets that have fallen and hit their heads can develop scar tissue in the brain when they heal, leading to seizures later in life.

Stroke

More correctly called “vascular disorders”, they involve damaged blood flow to the brain. The neurons that are normally nourished by these blood vessels can now have a problem.

Viral Disease

Rabies and Distemper are both viral diseases that can cause seizures in dogs.

Reactive Seizures

In this type of seizure the brain is reacting to a problem elsewhere in the body.

  • Hypoglycemia (low blood sugar)

This puppy has coccidia parasite, causing its blood sugar to plummet

  • Hypocalcemia (low blood calcium) This video shows an Iguana with twitching muscles caused by hypocalcemia. It is not a seizure. We show it to give an idea of how the bodies neurologic system is affected by hypocalcemia. You can learn more about this Iguana’s problem, which is called Metabolic Bone Disease

    Click Here to watch a Iggy

  • HypothyroidismA low thyroid level, called hypothyroidism, can precipitate seizures.
  • Kidney diseaseThe buildup of waste products in the bloodstream, called uremia, can cause seizures. Our Kidney Page has extensive detail on this problem.
  • Liver disease – Hepatic encephalopathy, a disorder of blood flow into the liver, can cause seizures. Our Liver Page explains it in much more detail.
  • Poisons The vast number of toxins that can cause seizures precludes us from going into detail on each one. One of the most common ones we encounter in our practice is Metaldehyde, also know as snail bait poison. Snail Bait Poison The active ingredient in this product is metaldehyde, a potent drug that will cause seizures in animals. There is no specific antidote- pets need to be sedated to stop the seizures, induced to vomit to rid the stomach of this poison, and even have their stomach flushed if necessary. After this initial treatment to prevent further absorption of the metaldehyde, we will give your pet intravenous fluids, sedate and even anesthetize it, check a blood panel for damage to internal organs, and monitor its life signs. If a dog that eats snail bait poison is brought to us immediately we can usually help them. This is a short movie of Eddie the morning after he was treated for snail bait poisoning. Notice how unsteady he is (called ataxia) when he lands after jumping up. His seizures are gone but he is still suffering the effects of the poison the next day

    Click Here to see Eddie

  • Other toxins that can cause seizures include:
    • Lead Poisoning-found in old paint, putty, tile, linoleum, used motor oil, drapery weights, bullets, and fish sinkers
      • Organophosphates and Carbamates – found in many different insecticides
      • Pyrethrins- found in insecticides
      • Strychnine- found in rat poison
      • Chocolate
      • Ivermectin- found in antiparasiticides
      • Mitaban- found in Demodex mange mite treatment
      • Caffeine- found in chocolate and NoDoz
      • Ethylene Glycol- found in antifreeze
      • Fungus
      • Some fungi can affect the brain and cause seizures. One of them is called cryptococcus.

This cat was negative for Cryptococcus

Non epileptic Seizures

Syncope

Dogs that have heart disease with an abnormal heart beat (called an arrhythmia), can pass out in a manner that looks just like a seizure. Sometimes syncope can be difficult to differentiate from a seizure. In syncope, a dog does not usually exhibit the motor activity (paddling) or urination/defecation symptoms seen in a seizure. This is one of the may reasons we follow a rigorous approach to the diagnosis of any disease.

Seizures in Cats

Cats have seizures much less commonly than dogs, and they don’t seem to have generalized seizures as often. Seizure symptoms that might occur in cats include:

  • Facial twitching
  • Salivation
  • Attacking invisible objects (although this can be normal behavior in some cats)
  • Running frantacially as if something unknown is chasing them
  • Colliding with objects (also ban be a normal behavior)

Secondary epilepsy tends to be more common in cats. In addition to the causes in dogs, common causes in cats might also include:

Depending on the cause, they are treated in a similar fashion.

In both dogs and cats we also classify seizures as to their cause when making a diagnosis. Those that occur directly in the brain are called intracranial. Examples include brain tumors, CNS infections and inflammations. Those that occur primarily outside the brain are called extracranial. Examples include hypocalcemia and hypoglycemia

Symptoms

Seizures commonly start while your pet is sleeping. Typical symptoms in a severe, or grand mal seizure, include: Falling

  • Loss of Consciousness
  • Extension of the limbs
  • Paddling of the limbs
  • Chomping at the jaws
  • Dilated pupils
  • Excess salivation
  • Defecation
  • Urination

Behavior changes during a milder seizure include:

  • Fear
  • Hysteria
  • Aggression
  • Barking or meowing
  • Hiding or cowering

In milder seizures your pet might remain conscious, and appear anxious or walk like it is drunk. Even though people like to compare this to “petit mal” seizures in people, it is not the same thing. Milder seizures might last for a few minutes, or could go on for hours, maybe even leading to a generalized seizure.

Pets appear to have an aura (preictal) prior to a seizure. They might be restless, seek attention, try to hide, whine, or tremble. After their seizure (postictal) they might show similar symptoms, even blindness, aggression, or sleepiness. The postictal stage lasts a variable period of time, up to hours after the seizure.

Diagnosis of seizures in dogs and cats

In most cases, by the time we examine a pet that has seizures, the seizures are no longer present. It is important to follow the tenets of the diagnostic process closely when making a diagnosis of seizures, especially since the syncope that occurs with heart disease mimics a seizure. A large part of the diagnosis in this disease is based on history, which you learned about when your linked to thediagnostic process page.

Signalment

Idiopathic seizures occur in any age dog or cat, particularly the breeds previously mentioned. Usually a dog with idiopathic epilepsy is between 1-3 years of age. Dogs not in this age range have a greater potential for secondary seizures as their cause.

History

Exposure to toxins, a prior history of head trauma, or concurrent diseases like liver and kidney disease, give us a clue to seizures and their cause. It is important to differentiate syncope from seizure, since some cases of syncope can look like your pet is having a seizure. If we suspect syncope we will perform tests to analyze the heart and lungs. You will find these tests in our heart page.

Physical Exam

In most cases the physical exam is normal. This is because most seizures are caused by idiopathic epilepsy. If your dog has a seizures caused by a brain tumor or infection/inflammation in the central nervous system (CNS), we might see neurologic signs like uneven pupils.

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This is a picture of an adult dog with diseased teeth, which might be an indication of Distemper when it was younger

In some cases of Distemper the pads might be thickened

As part of the physical exam on of our doctors might feel a need for a more detailed neurologic exam. Things that might be checked are:

  • Mental status – alert, depressed, unresponsive to stimuli, comatose, circling, head pressing, behavior change and disorientation
  • Cranial Nerves – menace response, pupillary light reflex (PLR), eyeball deviations (strabismus, nystagmus), oculocephalic reflex
  • Postural reflexes – conscious proprioceptive (CP), tremors, gait, extensor thrust, and wheelbarrowing
  • Spinal reflexes – pelvic limb (patellar reflex and perineal reflex), thoracic limb triceps reflex and biceps reflex)
  • Muscle – mass and tone
  • Pain and tactile reflexes – deep pain and light touch reflexes
  • Cutaneous trunci reflex
  • Tail tone

Diagnostic Tests

A Blood Panel and Urinalysis might give us a clue as to the secondary or extracranial cause of seizures. Careful interpretation is needed. If a dog has a low blood sugar (hypoglycemia) on the blood panel, it might be because the seizure activity has depleted its stores of glucose, not because it has hypoglycemia. This is why sometimes its a good idea to perform the exam well after a seizure has occurred, and the body has a chance to get back to normal.

Our routine blood panel also includes a thyroid check to make sure the level is not too low, which can precipitate a seizure.

Radiographs

Radiographs of the head of dogs and cats are complex compared to humanoids. There is a much smaller brain to view, the bones are more massive and overlapping, and there is great degree of variation among breeds. They can be used to diagnose hydrocephalus, trauma, or cancer, although they can’t be relied upon in most cases.

If we radiograph the hey can help us identify a secondary cause of seizures like an enlarged liver or kidney. We can sometimes see cancer on a radiograph as it has spread from its primary location to other parts of the body, particularly the lungs and lymph nodes. We might note fluid in the abdomen (ascites), an indication that a cat has FIP.

CSF Pressure

When a pet has a brain tumor there will be increased pressure within the central nervous system (CNS). This increased pressure, when it occurs, is measure by performing a spinal tap, and measuring the pressure with a manometer. Fluid that is obtained this way (called cerebrospinal fluid) can also be analyzed for inflammation and infection by our pathologist. This is how we diagnosis meningitis and encephalitis.

MRI

One of the most accurate and efficient ways to diagnoses the cause of a seizure, especially if there is a brain tumor, is Magnetic Resonance Imaging (MRI). It is also used to diagnose hydrocephalus, and blood vessel problems in the brain. If you double click on the picture below you will view a series of “slices” of the brain. The first picture shows a side view of a dog’s brain, and gives you an idea of the “slices” as the pictures continue on through the brain. This dog’s nose is on the far left. In slices 6-10 it will be obvious there is a problem when you see the large white mass in the middle of the brain – that is a tumor.

Click here to view a movie on MRI sequence

Treatment

In most cases by the time you can bring your dog to us for treatment the seizure has subsided. If your pet experiences a seizure, move any furniture out of the way, move things like lamps that might fall, remove other pets from the area, make sure it cannot fall down any stairs, and let the seizure run its course. Most will run their course within 1-2 minutes. Do not put your hands in your pets mouth to prevent it from swallowing its tongue- all that will do is get you bitten severely. If your pet turns blue during a seizure it is because its muscles of respiration (ribs, diaphragm) are locked, and it is not breathing temporarily. This problem will resolve itself, unless the rare occurrence of status epilepticus is present. Have a crate or airline carrier present to bring your dog to your veterinarian.

One rare but serious type of seizure is called status epilepticus, where the seizure lasts more than 5 minutes, it doesn’t stop at all , or it stops but returns soon after. This is a medical emergency, and requires the use of injectable medication, and even general anesthesia, to prevent it from progressing to a life threatening problem. If your dog is experiencing this problem call us immediately. If we are not available for some reason, you should have information at hand for a 24 hour emergency hospital close to you that will take care of you.

Idiopathic

Idiopathic epilepsy cannot be cured, only controlled, and once treatment is started, it is lifelong. Most dogs respond well to anticonvulsant medication give orally.

Deciding when to treat idiopathic epilepsy is just as important as how to treat. Some dogs only have 1 or 2 seizures per year, and don’t require treatment. Some dogs have seizures weekly or daily, and require treatment. Other dogs can be in the gray zone. They might have a seizure every 1-4 months, so making a determination to treat them is not so clear cut. If these dogs with infrequent seizures start having them more frequently, then we recommend anticonvulsant medication. As a general guideline, if your dog as 2 or more seizures in a 6 month period we should start an anti-convulsant therapy. The sooner we start on these dogs the better the long term outcome.

In some breeds the seizures will increase in severity, so it is wise to treat when seizures first appear and try to prevent this problem. This applies to Border Collie’s and Australian Shepherds. In these breeds more than one seizure medication needs to be started earlier in the course of disease if the first medication does not work well.

Every dog is different, and what works in one dog might not work in another. Doses sometimes need to be adjusted, and even combination therapy with several different medications might be needed to control the seizures.We don’t start a second seizure medication until we are sure the first medication is at optimum therapeutic levels with a blood panel.

These medications will take several days to take affect, so a seizure during that time might occur. Never abruptly discontinue them. Our goal is to balance seizure control with quality of life, using minimal medication. In most cases of idiopathic epilepsy we are able to achieve this goal, at least initially. Some dogs with epilepsy do not respond to medication.

Monitoring serum levels of anti seizure medications is important for the following reasons:

Determine effective drug concentrations after we have started treatment

Determine if a drug failure is due to a low level of the drug in the blood stream (inadequate dose), or if it is due to a drug that is not working, no matter what the dose.

Determine if treatment failure is caused by poor compliance

Prevent toxic effects if level is too high

Allows individual treatment

Phenobarbitol

One of the most common and effective medications for epilepsy is phenobarbitol, given twice to three times daily. The overwhelming majority of dogs are maintained at twice daily dosing in our hospital. It takes several weeks for the blood level of phenobarbitol to reach adequate levels, so there might be an occasional seizure during that time. Phenobarbitol works in the majority of dogs, is inexpensive, and safe, so it is widely used. The dose of this drug has a wide range, so if your dog is not responding to phenobarbitol, and the blood level of the drug is low to normal, we might increase the dose. Doses are changed gradually since it takes time for the effects of this drug to become apparent. An injectable version of this drug given intravenously (IV) to stop status epilepticus.

Never give your dog oral phenobarbitol if it is experiencing status epilepticus as described above- it needs to be seen by a veterinarian immediately. Never put your hands in the mouth of a dog having a seizure because you believe it is swallowing it’s tongue because it is turning blue. It is not swallowing it’s tongue, and all you will end up doing is getting injured.

Some dogs will be sedated initially, but may eventually return to normal activity. Other dogs might drink and urinate more than usual, and have an increased appetite. In rare cases the liver will become toxic due to this drug. This is why we check a full blood panel every 6 months while your pet is on this medication.

Phenobarbitol levels can be measured in the bloodstream, and are an important guide to proper dose of this drug. This will make sure we are at adequate levels in the bloodstream. One of the reasons a dog might continue to have seizures while on phenobarbital is an inadequate blood level. In this case we adjust the dose.

We recommend performing the phenobarbitol check every few weeks to months for the first few months of therapy in order to get an idea of how your pet reacts to the medication. The phenobarbitol level is interpreted in conjunction with the amount of seizures that is occurring. All adequately controlled dogs on long term phenobarbitol should have an exam, blood panel with urinalysis, and phenobarbitol level checked every 6 months at least. Dogs can become refractory to phenobarbitol, so it is imperative you give the medication as prescribed and monitor carefully so we can decide the best course of action in this case. It is not uncommon to have to increase the dose in some dogs.

When giving this medication on a twice daily basis it is important for busy households to give the medication as directed. Using a dedicated calendar to help you know when the next dose is due, along with monitoring seizure activity, is the best way to prevent inadequate dosing, especially when several people are involved with treatment. It is not unusual for dogs to spit out the pill on occasion, so always verify it went down the hatch. If you have trouble at any time giving this medication our nurses will assist you. They can review proper administration techniques, and will even give the medication for you in our hospital if necessary.

If your dog has gone over 1 year without a seizure me might slowly lower the medication over several months, and even stop it completely on a trial basis. This does not apply to every breed of dog.

Phenobarbitol has been around for a long time, so the price makes it the most cost effective anti seizure medication.

Imepitoin

This is another good first time treatment like phenobarbital. It is not easily monitored with a blood test to see if it is at a propper theraeutic level in dogs.

Keppra (levetiracetam)

This anti-seizure medication is used commonly as an additional drug given simultaneously when the first drug was not effective. It does not do as well when given by itself in the dog.

Potassium Bromide

This drug is used as a first drug for dogs with with a low initial frequency of seizures. If a dog is on phenobarbitol, and it is not adequately controlling seizures, even as we increase the dose, we will sometimes add this drug to the treatment regimen instead of Keppra. It can sometimes take several months for this drug to achieve enough potency in the bloodstream to prevent seizures. Whenever we have a dog on both medications we start dosing conservatively, and make changes gradually so the body has time to adjust.

It is also monitored with a blood sample periodically in a similar fashion to phenobarbitol.

Side effects can be similar to phenobarbitol, and also include an unsteady gait and inflamed pancreas (called pancreatitis). Liver toxicity to this drug is not usually a problem, so we can use it in cases where phenobarbitol is working but might be affecting the liver. Give it with a meal to prevent an upset stomach, and don’t change your dogs diet abruptly because salt in the diet influences how potassium bromide is absorbed.

Valium

Valium is given intravenously (IV) to dogs with status epilepticus. It is usually the drug of choice in status epilepticus because it is so effective. We might also give you a valium solution, to be given via rectum if your dog starts the continual seizure seen in status epilepticus. This gives you an effective treatment at home if this occurs, although if it does not work you need to seek medical care immediately.

In cats we sometimes use oral Valium (diazepam) as the first drug to control seizures. It is inexpensive and works well, although it might cause sedation.

Alternative Treatments

Vagal nerve stimulation, in 2 small studies, showed a significant (34%) decrease in seizure frequency in a population of 10 dogs.

Ketogenic diets are not effective, and might even cause pancreatitis.

MCT diets, which are medium chain triglyceride diets used for Cognitive Dysfunction Syndrome, have been shown to be effective in some dogs. The food here is Hill’s B/D (Brain Diet).

Omega 3 fatty acid supplementation is not effective.

Acupuncture- Not enough data is available in dogs. When data for humans is analyzed acupuncture is found to be of no value.

With the recent relaxing of marijuana (cannabis) laws in several states we might be able to find out if this works in a bona fide study.

Alternative Medications

Since seizures have been around for many years, well intentioned people have postulated many treatment regimens that range from high doses of vitamins to herbal treatments, all in the name of being better than drugs because thely are “natural”. These claims are yet to be proven, and until proper clinical trials are performed, these claims have no basis in fact, and are just a repeat of anecdotal evidence that has been around so long and repeated in print so often that it has become fact. Many of these “natural” remedies are drugs themselves, drugs in which no studies have been performed to see if they work and to make sure there are no toxic effects. Herbal treatments contain drugs, and just because they are natural does not mean they are not toxic.

Several drugs used in humanoid medicine are being investigated for use in the dog. We might use them if the standard medications are not working, although they are too new to know for sure how they react in the dog or cat.They have the ptential to be more toxic than the use of phenobarbitol and valium.

Long Term Plan

Everything regarding your pets seizures she be noted on a calendar. It will help us look for trends, and let us know if the medication is working. You should also note the dates your pet needs to return for an exam or blood sample.

Never discontinue medications just because your pet has not had a seizure in a while.

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Cushing’s (Hyperadrenocorticism)

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Cushing’s Disease (also known as hyperadrenocorticism- Cushing’s is easier to pronounce, so stick with that word) results when the adrenal glands secrete an excess amount of cortisone. It is the most common endocrinopathy (hormone disease) encountered in older dogs. This disease is the exact opposite of another endocrine problem in dogs called Addison’s disease (hypoadrenocorticism).

This detailed page will emphasize Cushing’s disease in dogs, with an explanation of how it differs from cats at the end. This is a complex hormonal disease that does not lend itself to a simple explanation or an easy diagnosis. Some pets have the symptoms, yet the tests are negative. Other pets have positive test results, but minimal symptoms that do not warrant treatment. Pace yourself-you might want to go to the bathroom before attempting this page!

We have a summary page on Cushing’s if the explanation on this page is too detailed for your needs.

This page contains graphic photos.


Several medical terms and abbreviations relate directly to Cushing’s:

cortisol– cortisone produced by the adrenal glands atrophy– decreased size of an organ
exogenous cortisone– supplemental cortisone hypertrophy– increased size of an organ
HAC – hyperadrenocorticism polyuria– excess urinating
CRH– corticotropin releasing hormone polydipsia– excess drinking
polyphagia– excess appetite PU/PD– polyuria and polydipsia
glucocorticoids– mostly cortisol, and a small amount of cortisone mineralcorticoid-hormone that affects sodium and potassium
hypoglycemia– low blood glucose level iatrogenic– caused by something a person does as opposed to happening naturally.
adrenalectomy– surgery to remove the adrenal gland. ACTH– adrenocorticotrophic hormone
hepatomegaly– enlarged liver adrenomegaly– enlarged adrenal gland
anabolic steroid– testosterone and its equivalent PD– pituitary dependent
catabolic steroid– cortisol and its equivalent AT– adrenal tumor

Anatomy

The adrenal glands are small paired glands buried in fat in the front of each kidney. Even though they are small, the cortisol they secrete, along with their other functions, have great significance to normal physiology. These guys are small but mighty, as you are about to learn!

The arrows point to the paired adrenal glands in front of each kidney. The extensive blood supply to the kidneys and adrenal glands is apparent. In the diagram they are easy to see. They are not so easy to see during ultrasound or exploratory surgery because normally they are small and buried in fat. They do not show up on an X-ray unless they are calcified.

Adrenal-Normal

A normal adrenal gland of a dog buried in fat just above the kidney. The white structure is the tiny adrenal gland, the dark structure below it is called the Phrenicoabdominal vein. It is a large vein for such a tiny organ, a testament to the importance of the adrenal gland.

Cushings-FerretAdrenal2

This is a normal ferret right adrenal gland, just under a lobe of the liver, which is pulled forward by the surgeon’s fingers

Cushings-FerretAdrenal1

This is a normal ferret left adrenal gland (just above the hemostat) buried in fat. The left kidney is the structure to the right.

Cushings-FerretAdrenal3

This is a picture of an enlarged left adrenal gland (arrow) that is buried in fat near the kidney (K). I is from a ferret that has adrenal gland tumor, so the gland is inflamed and easy to visualize. This is not necessarily the case in dog and cats with adrenal gland tumors.

The internal architecture of the adrenal gland is made up of several distinct zones.

  • Cortex

    The cortex (outer shell) of the adrenal gland is made up of 3 anatomical parts:

    • Zona Glomerulosa

      This is the outer layer of the adrenal gland. This section secretes the mineralcorticoid aldosterone. Aldosterone is vital to proper sodium and potassium regulation. Aldosterone has a role in maintaining blood pressure.

    • Zona Fasciculata

      This is the next layer as you go inward, and produces the glucocorticoid cortisol. The cells in this area are the ones that cause Cushing’s.

    • Zona Reticularis

      As we continue inward we come across this section that secretes the sex hormones known as androgens (male sex hormones), estrogen (female sex hormones), and sex steroids. These are usually secreted in such small amounts as to be of no major significance in healthy animals.

  • Medulla

    This consists of the very center of the adrenal gland. It secretes hormones called catecholamines. The two important ones are epinephrine (adrenaline) and norepinephrine.

Physiology

These tiny organs have a profound influence on many internal organs. The hormones they secrete work in unison with other internal organs, particularly the liver, and have an enormous effect on physiology. These hormones interact with many other hormones that have the opposite effect, usually in some type of feedback mechanism that is monitored by the brain. This interaction is complex, so only a summary of adrenal hormone physiology is presented.

The adrenal glands secrete several important hormones, most of which are synthesized from cholesterol. We will explain 3 of them; cortisol, aldosterone, and epinephrine:

  • Cortisol

    Cortisol is a hormone that is essential for life. Cortisol maintains a normal blood glucose level, facilitates metabolism of fat, and supports the vascular and nervous systems. It affects the skeletal muscles, the red blood cell production system, the immune system, and the kidneys.

    It is considered a “catabolic steroid”. This means it takes amino acids from the skeletal muscles and, with help from the liver, converts them to glycogen, the storage form of glucose. These functions are the exact opposite of “anabolic steroids”, the drugs that weight lifters take to increase muscle mass. The end result of this is an increase in the level of glucose in the bloodstream. The hormone called insulin has the opposite effect on blood glucose, adding to the complexity of this system. You can learn more about insulin by going to our diabetes mellitus page.

    The level of cortisol in the bloodstream continually fluctuates as physiologic needs vary. Surgery, infection, stress, fever, and hypoglycemia (low blood sugar) will cause cortisol to increase. This continual fluctuation adds to the difficulty of diagnosing Cushing’s, because the amount of cortisol in the bloodstream is so variable.  A test taken at one moment in time might have different results if taken later.

    To control the level of cortisol the hypothalamus and pituitary gland in the brain secrete chemicals into the bloodstream called releasing factors. In the case of the adrenal glands , the hypothalamus secretes a hormone called corticotropin releasing hormone (CRH). It goes to the pituitary gland and stimulates it to release a hormone called adrenocorticotrophic hormone (ACTH). It is the amount of ACTH circulating in the blood stream that tells the adrenal glands (specifically, the cells at the zona fasciculata) how much cortisol to secrete. There is a negative feedback loop that allows the hypothalamus and pituitary gland to refine precisely how much cortisol circulates in the bloodstream. The more cortisol secreted by the adrenal glands, the less CRH and ACTH secreted. This allows the body to precisely refine the level of cortisol, and to change the level rapidly due to changing physiologic needs.

    Numerous internal organs are affected by cortisol:

    • Muscles

      Cortisol is needed for proper muscle action, yet too much can cause the muscles to atrophy (shrink). This is due to their catabolic effect. This means that they literally cause the body to break down the amino acids in the muscle fibers in order to increase the blood glucose (sugar) level. Cortisol does this in a complex mechanism that involves the liver. The end result is the muscles become smaller. When this occurs at the abdominal muscles the abdomen appears pot bellied.

    • Bone

      Bone is made up of a protein matrix and calcium, both of which are affected by cortisol. Excess cortisol affects the protein matrix, decreases calcium absorption from the intestines, and increases calcium excretion by the kidneys. Skeletal mass decreases and bones become weaker.

    • Skin

      It causes atrophy of hair follicles and sebaceous glands, which leads to alopecia (hair loss). Elastic tissue under the skin is also affected, leading to thinner skin and adding to the pendulous abdomen. The disruption in the elastic tissue of the skin can also cause calcium changes in the skin. This might lead to areas where calcium builds up in small nodules. In cats the skin changes can become severe, and are referred to as fragile skin syndrome.

    • Vascular System

      Cortisol is required for maintaining the integrity of the lining of blood vessels. An excess will lead to thinning of these walls and the potential for rupture. The end result is a hematoma. Cortisol also increases the number of circulating red blood cells and helps maintain blood pressure.

    • Central Nervous System (CNS)

      Cortisol is necessary for the normal maintenance of brain functions. It can interfere with sleep and change the mood. You might notice these effects if your dog has Cushing’s or is given supplemental cortisone for treatment of a disease.

    • Liver

      Excess cortisol will increase the workload on the liver as it converts amino acids to glycogen. Pets with Cushing’s will commonly have an enlarged liver, known as hepatomegaly. You will be shown a picture of an enlarged liver on an x-ray in the diagnosis section.

    • Kidney

      An increase of cortisol increases the blood flow (also called GFR-glomerular filtration rate) to the kidneys. This will result in an increase in the amount of water and waste products filtered by the kidneys. Our kidney disease page has more details. This is one of the reasons why dogs with Cushing’s drink and urinate excessively (PU/PD), and urinate a dilute urine.

    • Immune System

      This is one of the more profound functions of cortisol. It decreases the inflammatory process and helps minimize an over reaction of the immune system to foreign bodies or infections. Unfortunately, it also suppresses the immune system to the point that the body has a hard time mounting a proper response. The body is more susceptible to infections, especially those caused by bacteria. This is one of the reasons why we routinely prescribe antibiotics when we prescribe cortisone if we suspect any type of bacterial or fungal infection.

  • Mineralcorticoids

    Aldosterone is the principal mineralcorticoid secreted by the adrenal glands. This hormone is secreted as a response from the kidneys when fluid volume in the bloodstream is decreasing. It involves other hormones called renin and angiotensin. The end result is an increase in sodium in the bloodstream, with a corresponding increase in blood volume and blood pressure. This hormone also interacts with and affects potassium levels. To further complicate the picture, ACTH also has an affect here, just like it does with cortisol.

    This part of adrenal gland physiology is not significantly altered in Cushing’s. Addison’s disease, which is the production of too little cortisone, has a greater affect on aldosterone.

  • Epinephrine (Adrenaline)

    This compound, technically called a neurotransmitter, also has hormone-like properties. It is a very powerful chemical that effects all organ systems. It acts very rapidly, with effects remaining only for a short period of time. It is the primary reason the body has the ability to respond to an emergency. This physiologic mechanism is also known as the “flight or fight” response.

    Upon stimulation of the central nervous system (ex.-fear or pain), the adrenal medulla is stimulated to secrete epinephrine into the bloodstream. We are all familiar with what happens next. The pupils dilate, the heart rate and blood pressure increase, and the palms get sweaty. Internally, the body is increasing the blood glucose level, the breathing passages are opened up, more red blood cells are secreted into the circulation, blood is shunted away from the skin and other internal organs, and blood flow is increased to the brain and skeletal muscles. All of this has the effect of bringing the brain and skeletal muscles extra glucose and oxygen, and accounts for the extra boost of awareness and energy we all feel at this time.

Cause

Pituitary Dependent (PD)

Up to 85% of all Cushing’s cases in dogs fall into this category. The pituitary gland is invaded with a slow growing cancer called an adenoma. This causes it to secrete an excess amount of ACTH. The cells in the zona fasciculata area of the adrenal glands respond to this excess ACTH by hypertrophying (enlarging) and secreting excess cortisol. It is this excess of cortisol that is circulating in the bloodstream that causes the symptoms we see in this disease.

This pituitary gland tumor can remain slow growing and not effect the pet any more than inducing Cushing’s disease. In 10-20% of these tumors they enlarge to the point that they will cause significant neurologic symptoms. Unfortunately, some of these neurologic symptoms mimic those seen as side effects to the medication used to treat Cushing’s.

Brain tumors are best diagnosed using an MRI (magnetic resonance imaging). This boxer has a large white tumor in its brain.

Non-Pituitary Dependent (AT)

In up to 15% percent of Cushing’s there is an actual tumor of one of the adrenal glands (sometimes both are involved). The tumor enlarges and secretes excess cortisol in the bloodstream. This excess cortisol is monitored by the hypothalamus and pituitary in the negative feedback mechanism, causing them to secrete less ACTH. Less ACTH in the bloodstream will cause the other adrenal (if it does not also have a tumor) to atrophy (shrink).

The benign version of this tumor occurs 50% of the time, and is called an adenoma. These dogs usually live a normal life. There is a small chance this adenoma can progress to a macroadenoma, where the prognosis is not as good.

The malignant version, which occurs the other 50% of the time, is called an adenocarcinoma. It can invade the primary vein returning blood back to the heart (called the vena cava), and spread from the adrenal gland to the liver, lung, kidney, and lymph nodes. Dogs with adenocarcinoma usually do not live more than a year.

Ferret-AdrenalNormalRIghtVC

The white arrow points to a small and normal right adrenal gland in a ferret. A lobe of the liver has been pulled forward so you can see the adrenal gland. The dark blue structure running horizontally is the vena cava (VC)as it coarses past the liver towards the heart. The close proximity of the adrenal to the vena cava and liver shows how easily a malignant tumor here can spread into the bloodstream and lodge elsewhere in the body.

Ferret-LargeRtAdrenal6

This is a very large right adrenal tumor, almost as large (and intertwined) as the kidney below it. Notice how the vena cava (dark blue vertical structure to the right of the tumor) goes in a different direction that the pictures above. Removing it is not possible without also removing the vena cava.

 

This chest radiograph follows the vena cava (arrows) as it passes through the diaphragm and continues from the liver to the heart. Unfortunately, the heart unwittingly can now pump cancerous tissue to the rest of the body.

Adrenal tumors are a common problem in ferrets. The adrenal tumor in this case does not secrete excess cortisol, so technically the disease is not called Cushing’s. The tumor causes an excess secretion of sex hormones, causing a different set of symptoms when compared to the dog and cat.

Iatrogenic

Exogenous (external or supplemental) use of cortisone is very common in medicine. It is a highly beneficial drug used to treat a wide variety of diseases. In some cases it is used as an emergency drug to literally save a life. Cortisone is beneficial in several disease categories:

  • Inflammation
  • Immune system
  • Neoplasia (cancer)
  • Cerebral edema (brain swelling)
  • Shock

Long term use of cortisone, in oral, injectable, or even topical form, might cause an animal to have the symptoms of Cushing’s disease. It all depends on the type of cortisone used, the dose it is used at, and the duration of use. As a general rule, once the original symptoms of the disease are treated with cortisone, we recommend decreasing its use, stopping its use, or finding an alternative drug. Sometimes this is not feasible though, especially in immune system diseases. The symptoms of these diseases far outweigh the potential side effects from this exogenous use of cortisone.

The level of cortisone that results from this exogenous use will cause the adrenal glands to atrophy. The negative feedback loop tells the brain there is plenty of cortisol in the bloodstream, so the pituitary secretes less ACTH. The pet has the symptoms of Cushing’s because cortisone is being introduced into its body, not because the adrenal glands are producing it in excess amounts.

Exogenous cortisone goes by several names. They come in injectable, oral, and topical forms, and tend to be more potent than the cortisol that is naturally produced by the adrenal glands. Some of the more common ones are:

 

 

Ectopic ACTH Syndrome

This is a rare version of Cushing’s that does not fall into any of the above categories. It can be found in association with cancer in the dog.

Symptoms

Some dogs with Cushing’s disease show the classic symptoms, while other show only a few vague symptoms. The classic symptoms are:

  • Polyuria/polydipsia (PU/PD)- This is excess urinating and excess drinking of water. It is one of the first signs of the disease, and usually precedes the other symptoms by a significant period of time. Several other important diseases cause these symptoms also, notably liver disease, kidney disease pyometra, and diabetes mellitus (sugar diabetes).
  • Pot bellied abdomen to the point a dog might look pregnant. It is due to hepatomegaly and abdominal muscle weakness (the mechanism of which was described above in the physiology section).
  • Thin skin and usually symmetrical hair loss along the trunk. The hair might grow in lighter in color or lose its luster. It might not grow in well at all. Calcium deposits under the skin, called calcinosis cutis, occur on occasion. Secondary skin infections called pyoderma are common also. The skin might also be hyperpigmented.
  • Muscle wasting over the head, shoulders, thighs, and pelvis.
  • Polyphagia- excess appetite. This is often interpreted by clients as being healthy, since most people think of a sick pet as not eating well. In this case your pet is over-eating, which is consistent with Cushing’s.
  • Other occasional symptoms include:
    • Pruritis (itchy skin)- due to secondary bacterial, fungal, or parasitic infections of the skin
    • Panting- due to affects on the lungs or the respiratory center in the brain
    • Obesity
    • Anorexia (poor appetite)
    • Straining to urinate or blood in urine due to urinary tract infection or bladder stone
    • Weakness
    • Depression
    • Aggression
    • Lethargy
    • Corneal plaques
    • Irregular heat cycles in female dogs
    • Testicular atrophy in males and clitoral enlargement in females
    • Emesis (vomiting) due to pancreatitis
    • Ataxia (incoordination), blindness, circling, and seizures due to a large pituitary tumor or spread of a malignant adrenal tumor
    • Lameness due to a ruptured cruciate ligament
    • Intra-abdominal bleeding near the kidneys (retroperitoneal space) resulting in anemia, weakness, and abdominal pain

Diagnosis

thorough approach is needed for a correct diagnosis of Cushing’s. In every disease we encounter we follow the tenet’s of the diagnostic approach to ensure that we make an accurate diagnosis, and also so that we do not overlook some of the other diseases that are common in pets as they age. Nature works in complex ways, and just because you have one disease does not mean you cannot get another one to complicate the matter.

The best way to diagnose this disease is with history and physical exam. If your dog has PU/PD, polyphagia, alopecia, muscle weakness, and excessive panting, then it most likely has Cushing’s. The adrenal screening tests are used to verify the diagnosis.

Some dogs have the normal symptoms of Cushing’s, but routine blood sampling does not bear this out. In these cases we will repeat the adrenal screening tests at some time in the future or even abdominal ultrasound to look at the actual glands.

1. Signalment

Cushing’s tends to be a problem that affects older dogs, usually greater than 6 years of age, with a median age of onset at around 10 years. The disease tends to have a slow and gradual onset, so the early symptoms are easily missed.

Several canine breeds are prone to getting Cushing’s:

Females and males get it at about the same frequency.  Neutered pets might be at higher risk of Cushing’s.

2. History

Cushing’s disease is suspected in any pet that has some of the symptoms described above, particularly the skin symptoms and the PU/PD. It is important to remember that some dogs do not show any symptoms early in the course of the disease. This is another reason for yearly exams and blood and urine samples in dogs and cats 8 years of age or more.

Since dogs with this disease do not have a poor appetite usually (they have the opposite as explained in the symptoms section above), owners will delay in bringing their dog in for an exam. They assume a good appetite means their dog is doing fine. They misinterpret the excessive appetite (polyphagia) as being a good sign, when in reality its a sign of disease.

Most people wait until a dog, that is normally housebroken, is now urinating in the house. This delay can make it difficult to treat, and will frustrate some people to the point they are contemplating euthanasia.

Other historical findings include skin infections that recur after antibiotic therapy is stopped. Some dogs have a history of pruritis (itchiness) if pyoderma is present.

A history of poorly controlled diabetes mellitus might also clue us in to Cushing’s.

3. Physical Exam

Routine physical exam findings might include:

    • Pot bellied abdomen
The abdomen of this dachshund is pot bellied due to Cushing’s. It could also have been due to fluid buildup from cancer or heart disease. An enlarged liver from a disease other than Cushing’s can cause this also.
    • Enlarged lymph nodes due to secondary bacterial infections or spread of an adrenal tumor.
    • An enlarged liver (hepatomegaly) might be palpated, along with smaller muscle mass (atrophy) in general.
    • Bruising (hematoma) might be observed under the skin, or when a blood sample is obtained.
    • Skin infections and wounds that do not heal or recur after antibiotics are stopped.
This dog has hair loss with a secondary skin infection called pyoderma
  • Hair loss (alopecia) that is symmetrical, along with thin skin, poor hair coat, and calcium deposits under the skin. Many skin conditions have similar symptoms, so numerous diseases have to be kept in mind. They include hypothyroidismskin allergiessarcoptic mangedemodectic mange, andRingworm.
  • Blood pressure might be elevated. This might cause a detached retina, picked up by an ophthalmic exam.
  • Heart disease, initially noted with the stethoscope as an increased heart rate, an irregular heart rate, or a murmur.

4. Diagnostic Tests

Several tests are used as an aid in making this diagnosis. Each test has its advantages and disadvantages.

  • Skin Scraping

    Skin scrapings are usually negative in Cushing’s, although demodex is possible as a secondary problem due to the immunosupression effect of cortisol. Long term use of cortisone orally can also predispose a pet to demodex due to its immunosuppressive effects.

  • Blood Panel

    A CBC (complete blood count) and biochemistry panel should be run on every dog 8 years of age or more, especially if they have any of the symptoms of Cushing’s.

    The CBC might show an increase in the number of red blood cells (RBC’s) and/or an increase in platelets (thrombocytosis). It might also show an increased WBC (white blood cell count), called leukocytosis. When these white blood cells are broken down, there are usually more neutrophils (neutrophilia), less lymphocytes (lymphopenia), and less eosinophils (eosinopenia). These white blood cell abnormalities can also be caused by the “stress response”. It is due to excess epinephrine and cortisol secreted in response to the actual process of taking the blood sample (those people that have passed out when their blood was taken are an extreme example of this). The excess cortisol secreted by the adrenals in the stress response is temporary, and part of normal physiology. It is not caused by Cushing’s disease.

    Cholesterol, blood glucose. triglycerides, and liver enzyme tests (ALT) might be elevated in Cushing’s. If a thyroid test is run it might be low or borderline normal.

    An elevated alkaline phosphatase (Alk Phos) is a consistent finding in Cushing’s. This is an enzyme that is located in the bile production area of the liver. The excess cortisol influences this enzyme, although growing animals, fractures, obstructions of the bile ducts, liver disease, drugs, pets with diabetes mellitus, and pets with cancer can all cause an elevated Alk Phos. A significantly increased Alk Phos alerts us to keep Cushing’s in our tentative diagnosis list.

    BloodPanel-AlkPhos

    This dog has a mildly elevated liver enzyme test and am elevated Alk Phos. If the signalment, history, and physical exam do not make us suspect Cushing’s we probably will not proceed to adrenal screening tests. This dog should be examined, and the blood should be checked every 3-6 months to see if these abnormalities are increasing.

    Cushings-BloodPanelPreTrt

    This dog with Cushing’s has several problems on the blood panel that are secondary to the Cushing’s:

    Increased WBC- 23.7

    Severely increased liver enzymes- Alk Phos- 5224

    Low thyroid- <0.5

    Low urine Specific Gravity- 1.008

    Cushings-BloodPanel

    This is the blood panel on the same dog with Cushing’s two weeks after starting treatment. The WBC’s are back to normal, and the Alk Phos is much less. As time we goes on and we continue treatment we can expect these values to continue to improve.

     

  • Urinalysis

    A normal specific gravity in a dog should be at least 1.025, and there should be no or minimal protein, glucose, WBC’s, or bacteria, as a general rule. With Cushing’s, the specific gravity of the urine might be low, the protein might be elevated, and a urinary tract infection might be present because of excess glucose in the urine.

    Urinalylsis-LowSG

This urinalysis of this dog shows a low specific gravity, which is consistent with Cushing’s

  • Skin Biopsy

    This test can give us an idea that Cushing’s is the cause of a skin problem. Many of the changes that are noted microscopically when evaluating the biopsy are also seen in other diseases, so it is not specific for Cushing’s. In spite of this fact, skin biopsies give us a large amount of information in skin conditions.

Radiography

Radiography might be of value if the adrenal glands are calcified (happens in up to 50% of adrenal tumors), otherwise the adrenals do not show up on a radiograph. Hepatomegaly can be seen on the radiograph, along with problems associated with other diseases in pets this age, so a radiograph can be highly beneficial to help rule them out. Radiography might also show osteoporosis (poor bone density) and calcification of soft tissue, both of which could be due to excess cortisol.

In this lateral view (laying on its side) of the abdomen, the kidney (K) closest to the arrow is the right kidney. The arrow points to where the right adrenal gland is located, although it cannot be seen since it is not calcified. The whitish area between the K’s is normal, and is caused by the effect of the 2 kidneys as they overlap.

This is a VD (ventral-dorsal, or laying on its back) view of a dog. The left kidney (K) is labeled, and the arrow points to where the left adrenal gland is located. There is some calcification in this radiograph, but it is not at the adrenal gland. Can you see it?

The liver (L) might be enlarged (hepatomegaly), although this enlargement can be found in other diseases, especially liver cancer and diabetes mellitus

  • Ultrasound

    This test can be highly beneficial in this diagnosis. The adrenal glands can be measured, and their internal architecture (called parenchyma) can be analyzed. It is not feasible to visualize all of the distinct different zones of the adrenal gland though. Other internal organs are also checked, giving us a substantial amount of information from just one test. A common incidental finding when we do a routine ultrasound on a dog suspected of having Cushing’s is to find this pet also has IBD (Inflammatory Bowel Disease).

     

    Ultrasound-adrenal

    This is what the right adrenal gland looks like during an abdominal ultrasound

    Cushings-USReport

This is the report

Screening Tests

This is the most reliable way to confirm a diagnosis of Cushing’s disease. These tests evaluate the interactions that are occurring between the hypothalamus, the pituitary gland, and the adrenal gland. The interaction between these glands is known as the hypothalmic-pituitary-adrenal axis. The first goal is to determine if Cushing’s disease exists. The next step is to determine if it is pituitary dependent (PD) or non-pituitary dependent (an adrenal tumor- AT). You might want to go back to the Cause Section above for a review before proceeding further.

Testing this axis is not as easy as it sounds. The mammalian body is a dynamic system with thousands of chemical reactions and interactions occurring simultaneously. Also, levels of cortisol are in a continual state of flux, depending on the time of day, the season, medications, diet, and stress levels. Underlying diseases like Urinary Tract Infections can affect these screening tests, and need to be controlled first. Because of all this variability, interpreting these tests can be problematic, and it is not uncommon to repeat them in the future to look for consistent findings and monitor trends.

We prefer to perform these tests when the stress level (for example a car ride to our hospital) is not high. It might be worth it to take your dog for a short walk after you park the car to let it settle down. One of the rests requires a 8 hour hospital stay.

The normal values in animals calculated by a particular lab are called reference values. They reflect 95% of the population, statistically the same thing as the values that fall under the bell shaped curve. Not every animal falls perfectly into this range, so there is always a degree of interpretation needed in determining whether a value is abnormal or not. Eventually, it boils down to a determination of probabilities, coupled with experience in diagnosing diseases in animals.

Sometimes the test results are borderline for the disease. In these cases we use other test like ultrasounds, or we repeat the tests 1-3 month down the road.

Two important concepts of laboratory testing relate directly to Cushing’s:

Sensitivity

The sensitivity of a test refers to the ability of that test to detect diseased patients. A Cushing’s test that is 95% sensitive will diagnose Cushing’s in 95% of all dogs with Cushing’s disease. 5% of the dogs in this scenario will have Cushing’s, even though their screening test for Cushing’s says they don’t have the disease.

Specificity

The specificity of a test refers to the ability of the test to detect only diseased patients. A Cushing’s test that is 95% specific means that 95% of the time if the test is positive for Cushing’s, the animal really does have Cushing’s. This means that 5% of the time the test will say an animal has Cushing’s disease when in reality it does not.

Animals that do not have Cushing’s disease might show up positive on these tests, while others that have the disease might be negative on these tests. Many times we have to play the odds based on probabilities. Due to this limitation in testing we recommend using these tests in combination, and repeating them if they do not give clear cut answers.

These tests sometimes come back as positive for Cushing’s when in reality other diseases are affecting the cortisol level. Some of these diseases (called non adrenal illness) include liver disease, chronic kidney disease, urinary tract infection, skin diseases, and uncontrolled diabetes mellitus. Also, cortisone and anticonvulsants can give false positives.

The most common screening tests are as follows. Now might be a good time to take that bathroom break before reading about these tests.

Urine cortisol:creatine ratio

In this test the level of cortisol in the urine is measured and used as an indication of the cortisol level in the bloodstream. Creatinine is measured to adjust for different levels of urine dilution. Our kidney page has more information on creatinine.

This test is useful as a screening tool when our differential diagnosis (you know what that means because you read theDiagnostic Process page) does not put Cushing’s on the top of the list. For example, we might use it in a pet that has PU/PD, but not the other signs of Cushing’s. It works in both dogs and cats.

Urine-Cort-Creat

This one came back positive, which means this dog might have Cushing’s, and it warrants further testing to confirm. If it was negative, we would probably not do any further testing for Cushing’s, unless we felt the test was improperly obtained, or the dog had significant symptoms of Cushing’s.

This test is easy to perform because all that is needed is a urine sample. We recommend you obtain this sample at home in the morning just after your pet wakes up. Bring it to us immediately for analysis by our lab. Obtaining it at home will minimize the stress of a car ride and a visit to our hospital, both of which will normally increase the level of cortisol in the bloodstream (remember the stress response?), thus affecting this test.

A high level of cortisol in the sample is suggestive of Cushing’s. Unfortunately, up to 80% of dogs that don’t have Cushing’s will also have an increased level. This means that the specificity is low.  If the cortisol:creatinine test comes back normal, then it is unlikely that Cushing’s is present, and we do not routinely recommend the following screening tests. A cortisol:creatinine ratio test that is high means Cushing’s might be present, and needs one of the other screening tests to determine if Cushing’s is indeed present.

ACTH Stimulation

This test checks for Cushing’s and Addison’s Disease. We tend to use this screening test when we suspect Iatrogenic Cushing’s. It is also used to monitor therapy on pet that is on medication for Cushing’s and Addison’s disease.

When a dog or cat is given ACTH by an injection the adrenal glands are stimulated to produce cortisol. By measuring this cortisol with a blood sample we can determine what reserve the adrenal glands have in the production of cortisol.

ACTH

This is what we use for the ACTH stimulation test

This test is very specific for Cushing’s, so false positives are rare compared to other screening tests. It is not as sensitive as other screening tests, particularly the LDDS test.  20% of dogs that have Cushing’s will be negative on this test. For this reason it is sometimes used in combination with the LDDS test.

ACTHReport

This dog does not have Cushing’s according to this test, but it might also be a false negative if the symptoms of Cushing’s are present

This is the only test that can distinguish between iatrogenic and naturally occurring Cushing’s. It is the only test that gives reliable results for a dog that has been on cortisone recently. It does not distinguish between pituitary dependent (PD) and non-pituitary dependent (AT-adrenal tumor).

A blood sample is taken to measure the resting cortisol level before ACTH is given. Two hours after the ACTH injection is given a blood sample is taken again to measure the level of cortisol. This two hours gives the ACTH injection time to stimulate the adrenal glands to produce cortisol.

In the dog, if the second test of cortisol is much higher than the first, it is suggestive of Cushing’s 80-95% of the time. It does not necessarily tell us if it is PD or AT, because this exaggerated response will occur in 85% of PD Cushing’s, and also 50% of those with AT Cushing’s. This test is not as reliable in cats, only 51% of cats with Cushing’s will show an exaggerated response.

If there is a reduced level of cortisol on the second blood sample, then either the dog has Addison’s disease or iatrogenic Cushing’s. This reduced response also occurs in dogs that are receiving Mitotane or Ketaconazole therapy for Cushing’s.

Between 5% and 20% of dogs that have Cushing’s (either PD or AT) will not show the exaggerated response expected with this disease. If this test is normal or borderline in a dog we suspect Cushing’s in these dogs then the test should be repeated at a later date, or the LDDS test should be performed.

Low Dose Dexamethasone Suppression Test (LDDS)

This is probably the best test when the history, physical exam, and routine blood panel and urinalysis are consistent with Cushing’s. We also use it when we feel there is no chance of Iatrogenic Cushing’s. It might also help differentiate between PDH and AT, but that is better determined by the HDDS test (High Dose Dexamethasone Suppression test). It only works in dogs because cats get a significant number of false positives.

It is sensitive for Cushing’s, because 85% to 100% of the time it finds a Cushing’s disease that is present. This means it does not diagnose a pet that has Cushing’s disease up to 15% of the time.

Its specificity is low though, meaning it might come back as positive for Cushing’s between 44% and 73% of the time when the dog does not have Cushing’s. If we are not sure of the results because of this variability, we might also perform an ACTH stimulate test.

This dose of dexamethasone (which is a version of cortisone) suppresses the adrenal gland from producing cortisol in normal dogs, but not those with Cushing’s. It achieves this suppression by interfering with the negative feedback mechanism. The dexamethasone is monitored by the brain as an excess of cortisone in the bloodstream, so less ACTH is secreted, and therefore less cortisol is secreted by the adrenal gland.

In this test an injection of Dexamethasone is given and cortisol levels are measured at 4 hours and 8 hours after the injection. Like the ACTH stimulation test, a pre-injection blood sample is taken to measure the resting cortisol level.

Cushing's-LDDSTestResults

Here are the LDDS test results on a dog that we suspected of having Cushing’s. What is your diagnosis in this case? It’s the same dog that had the ultrasound above.

High Dose Dexamethasone Suppression Test

This test is not used as a routine screening test. It comes into play when a dog already has Cushing’s and you want to be certain that it is not that rare case that is an adrenal tumor.

The protocol for this test is similar to the LDDS test, except of course, a higher dose of dexamethasone is injected. A dog with an adrenal tumor does not suppress cortisol levels from the baseline sample.

Summary of Cushing’s Screening Tests

Urine cortisol:creatinine

In some dogs with Cushing’s the excess cortisol that circulates in the blood stream will spill over into the urine. If this test is positive then a dog might have Cushing’s. If it is negative, there is a good chance it does not have Cushing’s.

ACTH Stimulation

A positive on this test gives a reasonably good chance that a dog has Cushing’s. It will not catch all dogs with Cushing’s, so a dog with a negative test might still have the disease. In general, we use this test to monitor patients that are already being treated for Cushing’s or Addison’s.

LDDS

This test will catch most dogs that have the disease, and is the test of choice for Cushing’s on dogs that have symptoms.  A negative on this test means that most likely the dog does not have Cushing’s. A positive on this test indicates that a dog might have Cushing’s. It is the most popular adrenal screening test.

If a dog has symptoms that are typical of Cushing’s, but all of these tests come back negative, we recommend repeating these tests every 1-3 months to monitor.

5. Response to Therapy

One of the tenets of the diagnostic process is whether or not a treatment that is instituted actually corrects the problem. This usually applies to Cushing’s. You should note significantly less PU/PD, improved skin, and a more active pet if the treatment is successful.

Treatment

Before we discuss treatment we need to keep things in perspective. This is a chronic disease, and most dogs do not die from this disease. We tend to treat when the symptoms described previously are affecting a dog’s quality of life or are a major nuisance to a pet owner. We do not routinely treat just because the tests say your dog has Cushing’s- the symptoms of the disease need to be present also. It might be years before this dog shows signs, if any, of Cushing’s.

Dogs that have significant symptoms of Cushings’ that have been confirmed by screening tests need to be treated to prevent potentially serious diseases secondary to Cushing’s that include Diabetes Mellitus, Urinary Tract Infection (UTI), pancreatitis and High Blood Pressure (Hypertension).

Urine C & S Report

To know if there is a Urinary Tract Infection a culture of the urine must be performed. This dog is negative for a UTI

Treatment can be drawn out, and involves significant time and expense to monitor your pet after we treat it. Also, in some dogs, treatment can lead to side effects that are more serious than the symptoms of this disease. One of these side effects includes a rare death, so we do not undertake treatment of this disease lightly.

This disease tends to occur in older dogs that commonly have other problems. Some dogs die of other diseases before the symptoms of Cushing’s become a significant problem. Treating Cushing’s does not necessarily give your pet a longer life. The goal of therapy is to give your pet a better quality of life.

Underlying problems need identification and treatment. The biggest underlying, overlooked, and serious problem we commonly find in dog with Cushing’s is Dental Disease. If your dog is hypothyroid the problem needs to be corrected with supplemental soloxine. Internal organ problems like kidney disease and liver disease need treatment for a successful Cushing’s outcome. Urinary tract and skin infections need to be cleared up with the use of antibiotics, and underlying diabetes mellitus needs to be regulated with insulin.

Some dogs with large tumors of the pituitary gland might initially respond to medical therapy for pituitary dependent Cushing’s. The Cushing’s symptoms, especially neurologic, might recur as the tumor progresses.

Several different treatment modalities have been developed for Cushing’s. Some are for Pituitary Dependent Cushing’s, some are for Iatrogenic Cushing’s, and some are for adrenal tumors.

Pituitary Dependent (PD) Cushing’s:

Trilostane

This is the newest treatment for this disease, and the one we recommend in most cases. Trilostane is an inhibitor of an enzyme called 3-beta-hydroxysteroid dehydrogenase. This enzyme is involved in the production of several steroids including cortisol. Inhibiting this enzyme inhibits the production of cortisol.

Trilostane Box

It will be given daily for the rest of your dog’s life

It is usually given once per day, but in some dogs, especially those with Diabetes Mellitus, the Cushing’s symptoms might not diminish at the once daily dosing and the medication needs to be given twice per day (every 12 hours). It always needs to be given with food for proper absorption. Some dogs do not absorb this drug even when treated with food. In that case, another drug needs to be used.

When we use this drug to treat your dog’s Cushing’s we will also give you a detailed flow chart of what to look for at home and when to return for additional test and monitoring. The ACTH stimulation test is used for monitoring purposes. Do not fast your dog on the day we do this test, and give the Trilostane as you always do.

Cushing's-FlowChart

This flow chart is helpful to monitor the adequacy of adrenal suppression by Trilostane

If your dog does not respond to Trilostane, and the ACTH stimulation test indicates inadequate adrenal suppression, the dose or frequency of administration might need to be changed.

If you are using the compounded version of trilostane, and your dog is not responding, switch to the name brand of trilostane (Vetoryl from Dechra).

Mitotane (o,p’-DDD)

This drug has been used to treat this disease for 30 years, and is  know by the trade name of Lysodren. It selectively destroys the zona fasciculata and reticularis, effectively limiting the amount of cortisol that these areas of the adrenal gland can secrete. Pets that are on insulin for diabetes mellitus need to have their mitotane and insulin doses adjusted downwards. It should be administered with meals to enhance its absorption. This drug is first administered at a loading dose for 7-10 days.

Side effects are not uncommon:

  • lethargy
  • emesis (vomiting)
  • diarrhea
  • anorexia (poor appetite)
  • weakness
  • ataxia (in coordination)

Side effects are due to the cortisol level being reduced below normal levels. Even if the cortisol level does not go below normal levels, a rapid decrease in elevated cortisol levels to the normal range can still cause these symptoms.

You need to closely observe your pet when it is on mitotane for any of the above side effects. If they occur you are to immediately stop medicating and call us. We will already have given you prednisone pills to give at home if side effects are significant.

After 7-10 days of loading dose the cortisol levels are assessed with the ACTH stimulation test. Do not give your pet any supplemental cortisone on the day of testing. The pre and post cortisol levels should be normal. If they are, then we will continue to use mitotane at a weekly maintenance dose to prevent the problem from recurring again. Once your pet gets to this point it is rare to need any supplemental cortisone pills.

Two long term effects can occur while on mitotane maintenance therapy:

  1. The Mitotane can be so effective that the adrenal glands do not produce enough cortisol for normal physiology. This is called iatrogenic hypoadrenocorticism. In these dogs we stop all mitotane therapy and use supplemental prednisone. Sometimes this side effect is permanent, and your dog needs to be on supplemental prednisone the rest of its life.
  2. It is not uncommon for relapses of Cushing’s to occur within 12 months, even while on the maintenance therapy. These dogs are again given a loading dose of mitotane, then converted to maintenance dose when cortisol levels are normal.Both of these effects emphasize the need for continual monitoring of your pet. This means close observation at home and ACTH stimulation tests every 3-6 months.

This drug controls the symptoms of Cushing’s 80% of the time.

Ketaconazole

This is a drug routinely used to control fungal infections. It has a different mechanism of action than mitotane. It inhibits cortisol production in dogs and humanoids by preventing enzyme pathways from functioning properly. Ketaconazole works for PD and AT Cushing’s. It is not as common to use as the previous 2 drugs.

It needs to be given at a test dose initially to watch for anorexia or emesis. If tolerated well, a loading dose is given for 7-10 days. After an ACTH test to determine if the cortisol is in the normal range, the drug is given every 12 hours for the rest of the dogs life. This is a more expensive proposition than mitotane.

Surgery

Surgery to remove both adrenal glands can also be used. It is an involved endeavor performed at a specialized surgical hospital. Post operative complications are common, and these pets need lifetime prednisone replacement therapy. As a result, this treatment is not commonly utilized.

Radiation

Recurrence of the symptoms of PD Cushing’s after initiation of therapy might be an indication of a large pituitary tumor. MRI is recommended to identify this type of tumor. Radiation therapy is recommended to prevent further progression of symptoms. Unfortunately, there are very few specialty radiation centers that can perform this procedure.

Iatrogenic Cushing’s

This form of Cushing’s is the easiest to treat since we are not giving a medication but taking one away. In most cases the elimination of exogenous cortisone will return your pet to normal function, although this might take several months. Some of the skin changes might take longer, and may not even return completely to normal. In some cases we use a decreasing dose of supplemental prednisone for several weeks to give the adrenal glands time to resume normal production of cortisol.

Adrenal Tumor (AT)

The surgery to remove the cancerous adrenal gland is called an adrenalectomy. It is a specialized surgery that is not routinely performed. Post operative complications are common.

Because the remaining adrenal gland is atrophied the dog needs to be supplemented with prednisone until the gland returns to normal function. ACTH tests are done every few months to determine when the gland is functioning normally, which can take up to 12 months.

Adrenal tumors can also be treated with mitotane at high doses and for a long period of time. Side effects are common at this dose, and relapses can occur. These dogs will also need to be on supplemental prednisone for the rest of their lives.

Feline Cushing’s

Cushing’s in cats is rare compared to dogs. One reason is because they tend to be more resistant to higher levels of cortisol, especially if iatrogenic. Most feline Cushing’s occurs in females. It can affect the ability to control the blood sugar level in cats with diabetes mellitus concurrently.

History

Cats do not show as much PU/PD as dogs do, unless they have diabetes mellitus concurrently. Most cats are presented in a more advanced state of Cushing’s disease because the early symptom of PU/PD is not observed. They might also have hepatomegaly, weight gain, pot-bellied appearance, and muscle wasting. Sometimes the skin is easily bruised and torn. This is called the fragile skin syndrome.

This picture is from an older cat that was at the groomer to be clipped. The skin literally peeled off like wet tissue paper when the groomer attempted to clip some mats. This is a serious problem and does not lend itself to easy treatment.

Diagnosis

Cats do not routinely show any changes on a regular blood panel or urinalysis. The most consistent finding on a blood panel is hyperglycemia. An elevated alkaline phosphatase occurs in only a minority of cases. Oftentimes the elevated alkaline phosphatase is due to liver changes from unregulated diabetes mellitus.

The urine cortisol:creatine ratio test is helpful in cats, especially since it is a relatively stress free test compared to blood sampling. If the test is normal then there is much less of a chance that Cushing’s is present. It the test is elevated it might be Cushing’s, but there are also other situations that cause this elevation.

The ACTH stimulation test is used, but two blood samples need to be analyzed at 30 and 60 minutes, instead of the 1 sample at 2 hours for the dog. This is because the increase in cortisol is variable in the cat. False negatives are common. False positives occur in stressed cats or those with non adrenal illness.

The LDDS test is used but the dexamethasone that is injected needs to be given at a higher dose. This test, when used in conjunction with the ACTH stimulation test, is one of the best ways to diagnose Cushing’s in the cat.

The HDDS test to differentiate PD from AT has not been refined to the point that is of diagnostic value.

In general, results of these tests can be variable, and must be interpreted in conjunction with the history and clinical findings. In light of the fact that Cushing’s is uncommon in cats, these tests need careful interpretation.

If the above tests suggest Cushing’s then radiology can be helpful since up to 30% of feline adrenal tumors are mineralized. Other radiographic findings include hepatomegaly and obesity. Ultrasonic evidence of an enlarged adrenal gland (especially if unilateral) or changes in internal adrenal architecture is strong evidence of an adrenal tumor (AT).

Adrenal tumors occur in about 20% of feline Cushing’s. They can be malignant or benign.

Treatment

Medical therapy is generally unrewarding. Ketaconazole can be used, but the effects are variable, and side effects can occur. Mitotane might help, along with metyrapone. Metyrapone may be more helpful as a presurgical stabilization prior to surgery. Anipryl has not been used in cats.

Surgery is needed to remove one of the adrenal glands if the gland has a tumor, and both glands if the problem is PD. If both glands are removed the cat has to be on supplemental cortisone and mineralcorticoids for the rest of its life. Some cats with concurrent diabetes mellitus will no longer have the disease when their adrenal tumor is removed.

Unfortunately, cats with Cushing’s can be poor anesthetic risks due to diabetes mellitus and fragile skin. When this occurs we sometimes will use medical therapy to help control the problem and make our patient a better anesthetic risk.

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Hypothyroidism

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The most common hormone problem encountered in dogs is hypothyroidism. It results when the thyroid gland does not secrete an adequate quantity of thyroid hormone called thyroxine. Many internal organs are affected, and the resulting problem depends on which organs are most affected.

Cats do not get this problem, but get an opposite problem called hyperthyroidism. Their problem involves excess thyroxine and its effect on the internal organs.

Anatomy

The thyroid gland is a small gland located at the throat, near what might be termed in people the “adam’s apple”. It has two lobes, and can be felt with careful palpation.

In this view of the thyroid gland you can also see the yellow colored parathyroid gland at the far left and the lymph node underneath

Physiology

The role of the thyroid gland is to take iodine and convert it into the 2 main thyroid hormones; thyroxine (T4) and triiodothyronine (T3). T4 and T3 then circulate through the bloodstream and affect the metabolism of every cell in the body.

To control the level of these hormones the hypothalamus and pituitary secrete compounds called releasing factors. In the case of the thyroid gland, they secrete a releasing factor called thyroid stimulating hormone (TSH). It is the amount of TSH circulating in the blood stream that tells the thyroid gland how much thyroxine to secrete. In a very refined feedback mechanism between the hypothalamus, pituitary, and thyroid gland, the cells of the body get just the right amount of T4 and T3.

Thyroxine circulates throughout the bloodstream and affects almost all organs. It plays a major role in controlling metabolism, and is needed for growth.

Cause

Primary (naturally occurring)

Primary hypothyroidism accounts for almost every case. It has 2 main causes:

Lymphocytic thyroiditis

This cause, also known as autoimmune thyroiditis, occurs when the body makes antibodies against the thyroid gland. This effectively destroys part of it, so it has less thyroxine to secrete into the bloodstream. It is one of the most common causes of primary hypothyroidism.

This cause of hypothyroidism can start early in life. Symptoms will appear when it progresses to the point that the reserve power of the thyroid gland is affected.

Idiopathic

In this form we do not know the cause, which is why it is called idiopathic.

Secondary

Secondary hypothyroidism accounts for only a small percentage of cases. It arises when there is a lack of TSH, or secondary to some medications or diseases.

Miscellaneous

There are other causes of hypothyroidism that are encountered only rarely.

Symptoms

Thyroxine affects many internal organs, so a deficiency can have various symptoms. Classic symptoms include mental dullness, lethargy, obesity, and heat seeking behavior, although many hypothyroid dogs do not have any of these symptoms.

Early diagnosis of hypothyroidism is beneficial because a dog can have this disease and not show any symptoms for many years. In every disease we treat, the sooner we start the better-this applies particularly to hypothyroidism.

Integumentary System

This is the most common manifestation of hypothyroidism. Typical skin symptoms include symmetrical hair loss (alopecia) along the trunk, although the hair loss is not consistently symmetrical. The hair coat is thin and dull, the hair easily falls out, it grows back slowly, and shedding occurs more often. Sometimes the hair coat resembles that of a puppy. Alopecia, if it occurs, is more common at pressure points and the tail.

The skin might be cool to the touch and be darker (hyperpigmentation) than normal. A leathery feel called lichenification might also exist. Hyperpigmentation and lichenification usually occur when the problem has been long-standing. Also, the skin might be greasy due to seborrhea, and inflamed due to secondary bacterial or fungal infections. These secondary complications might cause excess scratching (pruritis) and odor.

They skin lesions present in hypothyroidism mimic those in other skin conditions, especially allergies.

This terrier has hyperpigmentation on its neck. Hypothyroidism is not the only potential cause of this condition

The ears can be affected, resulting in hair loss, inflammation and infections.

Neurologic System

Neurologic signs might be seen, and include dullness, mood swings, muscle wasting on the head, facial paralysis, head tilt, disorientation, muscle weakness or paralysis, and lameness. On very rare occasions there will be seizures, and coma. Two specific diseases associated with hypothyroidism are megaesophagus and laryngeal paralysis. A loss of smell and taste are also possible.

This is a severe head tilt in a cat. There are numerous other causes to head tilt, most of them are more likely than hypothyroidism.

Ocular System

The cornea might undergo fat (lipid) deposits or become ulcerated. Changes with adequate tear production along with internal structures of the eye could occur.When a dog does not produce enough tears to keep the cornea moist it develops a disease called keratitis sicca. A tenacious discharge adheres to the eye and makes it susceptible to many problems.

This is typical of that discharge

Gastrointestinal System

Diarrhea, constipation and vomiting, if they occur, could occur in hypothyroid dogs.

Cardiovascular System

Abnormalities in heart strength, rate and rhythm, along with atherosclerosis, could occur with hypothyroidism.

A Holter counter is used to monitor the heart rate and rhythm over 24 hours so as not to miss any short arrhythmia episodes

This is the report we get 24 hours later

 

Immune System

Inadequate thyroxine makes the immune system less effective at fighting infections, especially the bacterial skin infections (pyoderma) that occur secondarily. Suppression of the immune system might even increase susceptibility to demodex.

Hematologic System

Anemia is the most noted symptom. anemia is not a disease but a sign of disease. It occurs when the red blood cells are low. There might also be a bleeding tendency, low white blood cells from bone marrow suppression, and low platelets.

This blood sample shows three different tests on a CBC that check for anemia. All three are low

RBC- red blood cell count

HGB- Hemoglobin level

HCT- hematocrit

Reproductive System

Breeding dogs might have abnormal heat cycles, infertility, and high puppy mortality. Testicular atrophy and low sperm, or no sperm.

Endocrine System

In addition to low thyroxine, hypothyroidism is implicated in sugar diabetes (diabetes mellitus) and addison’s disease (hypoadrenocorticism).

Musculoskeletal System

Thyroxine is essential for the development of bones in young animals.

The arrow point to growth plates, areas of bone growth that allow the bones to grow longer. The top arrow points to the end of the thigh (femur) bone, the bottom arrow points to the beginning of the shin (tibia) bone.

Diagnosis

Due to the vast number of organs influenced by thyroxine, and the fact that many skin conditions have similar symptoms, numerous diseases have to be kept in mind when making a diagnosis. These include Cushing’s diseaseskin allergiessarcoptic mangedemodectic mange, and Ringworm.

thorough approach is needed for a correct diagnosis of hypothyroidism. In every disease we encounter we follow the tenet’s of the diagnostic approach to ensure that we make an accurate diagnosis and that we do not overlook some of the diseases that are also encountered in pets as they age.

  1. Signalment

    Hypothyroidism can occur at any age, although it tends to be a problem that affects middle aged and older dogs, especially the larger breeds.

    Several canine breeds are prone to getting hypothyroidism. :

    • Chow
    • Great Dane
    • Irish wolfhound
    • Cocker spaniel
    • Golden Retriever
    • Poodle
    • English bulldog
    • Schnauzer
    • Boxer
    • Dachshund
    • German Shepherd
    • Doberman Pinscher
    • Borzoi
    • Irish Setter
    • Old English Sheepdog
    • Miniature Schnauzer
    • Airedale terrier

    Females and males get it at about the same frequency, neutered pets might be at higher risk of hypothyroidism.

Our Breed Predispositions page has information on common diseases in many breeds in addition to low thyroid. You will find them in our Learning Center.

  1. History

    Hypothyroidism disease is suspected in any pet that has some of the symptoms described above, particularly the skin symptoms. It is important to remember that some dogs do not show any symptoms early in the course of the disease. This is another reason for yearly exams and blood sample with thyroid test in dogs and cats 8 years of age or more.

    Other findings include skin infections that recur after antibiotic therapy is stopped.

  2. Physical Exam

    Routine physical exam findings might include:

    • Ear problems
    • Slow heart rate or abnormal heart rhythm
    • Body temperature might be lower than normal
    • Pale mucous membranes due to anemia
    • Enlarged lymph nodes due to secondary bacterial infections
    • Alopecia that is symmetrical
    • Skin conditions in general
  3. Diagnostic Tests

    There is no one test that definitively diagnoses hypothyroidism, save for a thyroid biopsy.

    Blood Panel

    A CBC (complete blood cell) and biochemistry panel should be run on every dog 8 years of age or more, especially if they have any of the symptoms of hypothyroidism.

    The CBC might show anemia or an elevated WBC (white blood cell count). The anemia is due to thyroxine’s direct effect on red blood cell production, the elevated white blood cell count (leukocytosis) is due to secondary bacterial infection.

    The biochemistry panel might show an elevated cholesterol. Diet can influence this test, along with how long after a meal was the blood sample for this test obtained. To be accurate there should be a 12 hour fast when assessing cholesterol levels.

    Liver tests might also be elevated, presumably from fatty changes that occur in the liver due to abnormal metabolism.

The biochemistry panel is comprehensive. This high cholesterol alerts us to keep hypothyroidism in our tentative diagnosis list. This dog also has high liver enzymes and a low sodium/potassium ratio, which could indicate primary liver disease or Addison’s disease.

Thyroid Test

Many factors affect the level of thyroxine that circulates in the bloodstream, including normal fluctuations. As a result, there is no blood sample that definitively makes a diagnosis of hypothyroidism. Over the years many different test have been developed to help us detect adequate levels of thyroxine in the bloodstream. Our goal is to diagnose those cases where the problem is not so obvious, and also not to over diagnose this condition.

Our routine blood sample has an add on test called a T4 test. If this test is normal, everything else being equal, a dog probably does not have hypothyroidism.

 This dog has a low T4 test, so it might have hypothyroidism, but not necessarily 

  1. If the thyroid test is low or low normal, then 2 main scenarios are possible:The first scenario is called the sick thyroid syndrome or nonthyroidal illness (NTI). In this situation the thyroid gland is normal, but there are factors that are suppressing it from secreting a normal amount of thyroxine into the bloodstream. These factors include medications like cortisone, valium, anticonvulsants, and sulfa antimicrobials. Diseases like Cushing’s diseasediabetes mellituschronic renal failureliver disease, and addison’s disease can also cause NTI. When these factors are corrected, or these diseases are treated, the apparent hypothyroid problem corrects itself. No treatment with supplemental thyroxine is needed.
  2. In the second scenario the thyroid gland is having a problem secreting adequate thyroxine due to one of the causes previously mentioned in the causes section. This is the hypothyroidism we need to treat with supplemental thyroxine.
    How do we differentiate between a true hypothyroidism from the sick thyroid syndrome. We have another blood sample that aids us, called the free T4 test by equilibrium dialysis. If this is low, and the signalment, history, and physical exam are consistent with this disease, then a diagnosis of hypothyroidism is made.

This dogs T4 level by equilibrium dialysis is low, so it most likely has hypothyroidism

Skin Biopsy

Biopsies of the skin can show changes associated with hypothyroidism. These changes can also occur with other skin conditions though, especially those involving the endocrine system.

The comments section of this skin biopsy report mentions endocrinopathies (hormone diseases like hypothyroidism) and corticosteroids (cortisone) as possible additional causes of this dogs skin problem.

TSH Test

This is the most reliable test to confirm a diagnosis of hypothyroidism. It eliminates some of the variables that suppress thyroxine production by the thyroid gland. Unfortunately, it is difficult to find TSH of animal origin. Human recombinant TSH is a possible replacement, but cost might preclude its use.

Thyroid Biopsy

An actual biopsy of the thyroid gland can be taken. This test is rarely utilized since there are many other good tests that are not so invasive.

Radioiodine Uptake

Radioactive Iodine can be used to outline the thyroid. We tend to use this test much more often in feline hyperthyroidism.

  1. Response to Therapy

    One of the tenets of the diagnostic process is whether or not a treatment that is instituted actually corrects the problem. This might apply in hypothyroidism, but it might not. In some situations we have no choice but to try supplementation. We reserve this for cases when the thyroid tests are suspicious (normal but at the low end of the normal range), we find no evidence of other disease processes, and the dog has symptoms consistent with hypothyroidism.

    This approach has disadvantages though. Since thyroxine affects metabolism, an increase in metabolic rate due to supplemental thyroxine might correct some of the symptoms encountered, even increasing hair growth. This does not necessarily mean that these symptoms that were consistent with hypothyroidism were actually caused by hypothyroidism. A delay in the correct diagnosis leads to a delay in proper therapy and a worsening prognosis.

    Treatment

    If a dog has sick thyroid syndrome it is treated by correcting the underlying problem. This might includeantibiotics for secondary bacterial infections, or the elimination of drugs like cortisone.

    When hypothyroidism is correctly diagnosed, the treatment, called levothyroxine (T4), is continued for life. Levothyroxine has various trade names, including Soloxine and Synthroid.

This is the brand we use. It is best to stay away from generic levothyroxine because it is not absorbed as well as the name brand version.

 

Medication is given every 12 hours. A thyroid level needs to be checked initially at 1 month to make minor adjustments. The thyroid pill should be give 4-6 hours prior to the recheck blood test. It is then checked every 6 months in order to refine the dose, because the body does change in the amount of thyroxine released by the thyroid gland. Also, as pets age, their cells vary in their need for thyroxine.

In the first week of treatment many dogs will be more alert and more active. Within one month improvement in problems related to metabolic changes will be noted, and within 2 months most skin conditions will be improved. If there is no response to therapy within 3 months, and the proper dose and type of levothyroxine are being used, then further diagnostic tests are needed to look for other diseases. It might take 6 months or more for all changes to return to normal.

It is possible to overdose your dog with levothyroxine. Symptoms include excess drinking and urinating, restlessness, and increased appetite. If you suspect this is occurring stop medicating and bring your dog in for an exam. Checking the thyroid level every 6 months will help eliminate this problem.

Pets that have heart disease, diabetes mellitus, or Cushing’s Disease(hypoadrenocorticism), may need altered doses of medicine if they occur concurrently with hypothyroidism. The dose of levothyroxine in these pets, if used at all, needs to be conservative to prevent other problems.

An additional treatment modality is called VNA. It is a non-invasive and non-painful way to stimulate the nervous system to help the thyroid gland heal on its own.

Prevention

Since this disease has a strong genetic component selective breeding can help minimize occurrence. Screening for anti thyroid antibodies in breeding animals can be utilized once they have reached puberty. These antibody tests are sent to special labs at Michigan State University or Cornell University.

The use of VNA can have substantial positive effects in this disease.

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Kidney Disease (Chronic Kidney Disease) or Chronic Renal Failure

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One of the more common conditions encountered in pets, especially as they age, is kidney (renal) disease. This disease is particularly prevalent in cats, and is called chronic kidney disease (CKD). It is also known as chronic renal failure (CRF). Once a pet has CKD the changes in the kidney are irreversible, so it is important to catch this disease early to mitiage its progression.

Because of the prevalence of this probem in cats, and the fact it is incurable, all cats starting at 8 years of age should be fed a diet called Hill’s K/D Early Support. This will go a long way in helping prevent the onset of kidney disease in cats. We want to start this food long before your cat starts losing weight and before the kidney tests on the blood panel are showing a problem.

25% of the blood ejected from the heart on every heartbeat goes directly to the kidneys, a testimonial to how important the kidneys are to health. When a pet has chronic kidney disease there are many issues that need to be addressed for a successful outcome. You will learn about them in more detail later in this page. The more important ones are:

  • Protein and phosphorous regulation
  • XS protein in the urine
  • Elevated creatinine in the bloodstream
  • High blood pressure
  • Anemia
  • Dehydration and electrolyte imbalance
  • Low pH in the bloodstream
  • Stomach and intestinal ulcers
  • Body condition score

We use the IRIS (International Renal Interest Society) system of classification at the Long Beach Animal Hospital to better diagnose and treat CKD. IRIS is a group of veterinary kidney specialists throughout the world that have studied this disease extensively and have set standards for diagnosis and treatment. At the end of this page there is a link to this organization for more information on how they stage kidney disease.

The IRIS system stages kidney disease from Stage I to Stage 4. We want to catch those pets that are at Stage I so we can initiate treatment then, and have a much better outcome. If you start your cat on K/D early support you are already way ahead of the curve.

In this staging system we are closely monitoring several important parameters:

  1. Creatinine trends
  2. Protein in the urine
  3. Blood Pressure
  4. Body condition score

urinalysis-protein-cat

This cat has a normal creatine, so the kidneys seem OK on the blood panel. The urinalysis shows a protein level of 1+. This could be the sign of CKD in this cat, and should be treated early if further tests indicate it does have CKD. Just changing to a food like Hills K/D can make a big difference on a cat like this if started early in the course of the disease, and before other problems related to CKD appear. 

In addition to these parameters, the following general parameters are also checked for early signs of chronic kidney disease. These parameters are also used to monitor progression and success of treatment:

  1. Small kidneys on abdominal palpation
  2. Radiographic or ultrasound evidence of small kidneys
  3. Decreased urine specific gravity

This page describing kidney disease is very thorough with significant information on anatomy, physiology, and pathophysiology. How the kidneys regulate water consumption and urine production are controlled by complex and highly refined interactions between plasma osmolality, fluid volume in the bloodstream, the thirst center in the brain, the kidneys, the pituitary gland, and the hypothalamus. Even though this page is thorough, the physiology of the kidneys is complicated, and only a summary of how the kidneys work is prestented on this page.

We have information on treatment towards the end of this page if you want to bypass all the background information and skip right to it. We also have a summary page on kidney disease if this page is too detailed.

Pets that have kidney disease commonly have other problems that need careful attention if the kidney problem is to be treated successfully. Some of these other common problems are:

Hyperthyroidism

 Heart disease

Inflammatory Bowel Disease

 Dental disease

 Sugar diabetes (diabetes mellitus)

 High blood pressure (hypertension) – leading to blindness.

Several medical terms are used when describing kidney disease:


Renal anatomy

The kidneys are such a vital organ that 25% of the blood that enters the circulatory system from each heartbeat goes directly to the kidneys through the renal artery. With such a high metabolic rate the proper functioning of this organ is critical to health. The high metabolic rate and importance of this organ makes the kidneys susceptible to many problems.

The kidneys are located in a specific area of the abdomen called the retroperitoneum. This area is a small indentation at the top of the abdomen just underneath the spinal vertebrae. This location, in addition to being surrounded by a fat, affords added protection to this vital organ.

OLYMPUS DIGITAL CAMERA

The kidney is normally covered in a layer of fat

This is a kidney with surrounding fat removed. You can see the dark liver on the far left, and the renal vein as it leaves the kidney and mergers with the vena cava. The blood from the vena cava flows into the liver and then directly to the heart. This is the blood that has been filtered of impurities and is reentering the circulation. You can not see the renal artery or ureter, they are buried in the white fat at the top of the kidney.

Blood enters the renal artery and flows into the nephron where it is filtered. The blood from the renal artery that has been filtered now flows out of the renal vein where it goes back into the circulatory system. The impurities that the nephron filters out of the blood collect in the renal pelvis and eventually out into the ureter in the form of urine.

The primary functional unit of the kidney is the nephron. Each kidney has upwards of one million nephrons, so obviously they are microscopic in size. Every nephron is a self contained unit that can form urine by itself. Not all nephrons are used at the same time, which gives the kidneys the capacity to increase their workload if called upon. This reserve capacity is lost when chronic renal failure occurs. These pets (especially cats) outwardly appear normal, but have greatly reduced ability to adapt to changing physiologic needs. Being chased by a dog, not having enough water to drink, etc., can send them into a crisis, requiring immediate medical care.

This is the cut section of an actual  kidney from a cat

This is a kidney, turned partially to the right sideways to the one above, as we view it with the ultrasound. The yellow line is measuring its length.

The important anatomical components of the nephron are described below:

  • Afferent Arteriole

    This small artery is one of the many small branches that come off the renal artery as it enters the kidney. It supplies the glomerulus with blood. Eventually filtered blood returns to the renal vein.

  • Glomerulus

    This is a collection of many small blood vessels at the end of the afferent arteriole. Normal pressure of the blood in the glomerulus causes fluid to flow into a collecting area called Bowman’s capsule.

  • Bowman’s Capsule

    Fluid that collects in Bowman’s Capsule eventually flows into the tubules. It is in these tubules that waste products and excess electrolytes are filtered out of the fluid, and normal blood constituents like protein and glucose are absorbed back into the bloodstream. When a diuretic like Lasix is given it acts on these structures.

  • Collecting Ducts

    At the end of the tubules is the collecting duct, where the urine produced starts to flow out of the nephron. Other nephrons deposit urine in collecting ducts as these ducts flow into the renal pelvis. From the pelvis the urine flows into the ureter and bladder.

Renal Physiology

The kidneys have a profound affect on almost all the physiologic processes of the body. The mechanism by which the kidneys perform these functions is extremely complex, the most important of which will be summarized:

  • Fluid Regulation

    In relation to the kidneys, the brain monitors bloodstream levels of water, waste products, electrolytes, and red blood cells. The circulatory system also has receptors like the brain to monitor blood volume also. If the water level is too low, as occurs with dehydration, the brain secretes more of a hormone, called ADH (anti-diuretic hormone), into the bloodstream.

    As a result, the kidneys excrete less water into the urinary tract, retaining more fluid in the bloodstream to counteract the dehydration. The brain also increases thirst simultaneously. The end result is less urination. The urine that does get excreted is more yellow than usual due to a greater concentration of waste products being excreted in relation to the amount of water being excreted. The only thing we notice is that we urinate less and it is more yellow in color.

    As we drink water to quench our thirst and rehydrate, the body notes this change and the brain secretes less of the hormone called ADH. Now when we urinate more water is excreted by the kidneys, and our urination occurs with a dilute urine in greater quantity. So, the ability to concentrate the urine and dilute the urine is an important function of the kidneys. It is a fine tuned mechanism that is closely regulated to maintain optimum amounts of fluid in the bloodstream and organs.

    As a fun fact, it is the inhibition of ADH by alcohol’s depression effects on the brain that causes excess urination when drinking alcoholic beverages. Eventually this excess urination causes dehydration, leading to that inevitable curse called a hangover.

    The kidneys also secrete a hormone called renin. Through a complicated set of biochemical pathways this ultimately leads to an increase in salt (sodium) in the bloodstream. Sodium pulls water towards it, so more sodium means more fluid in the bloodstream. It will have an effect on blood pressure, which you will learn about later.

  • Waste Product Regulation

    The brain also monitors waste products that build up in the bloodstream. These waste products are the end product of normal metabolic processes, especially the metabolism of proteins. They are called nitrogenous waste products, and are measured by a blood parameter called blood urea nitrogen (BUN). Another waste product that is closely regulated by the brain and kidneys is called creatinine. It is the end product of the metabolism of muscle.

    The kidneys also excrete toxins and foreign substances that are introduced into the body. Almost every medication given, either orally or by injection, is eliminated to some degree by the kidneys.

    The rate at which fluid flows into the glomerulus is important. This is called the glomerular filtration rate (GFR), and is measured in ml/minute. Too small a flow and waste products are not eliminated, a problem encountered during dehydration. Too much flow and normal blood constituents like protein are excreted when they shouldn’t be.

  • Electrolyte Regulation

    Electrolytes are also of importance in relation to the kidneys. Sodium is of extreme importance in the normal functioning of all cells. It allows nerve impulses to occur and is critical in the regulation of water levels in the bloodstream. Through the release of a hormone called angiotensin the kidneys regulate fluids levels of sodium in the bloodstream. This has a major affect on the blood pressure. Potassium is also a critical electrolyte. Potassium levels need to be kept at a very narrow range to prevent serious consequences like heart irregularities.

  • Hormone Regulation

    The kidneys also regulate calcium and phosphorous by hormones called calcitrol and parathyroid hormone, and by regulating vitamin D. Vitamin D allows the absorption of calcium from the intestines. If the kidney disease progresses long enough the excess secretion of parathyroid hormone causes the bones to become swollen and fibrous as the body attempts to maintain a normal calcium level. This is called renal osteodystrophy.

    As the bones become more fibrous the marrow is not able to produce red blood cells as effectively. This leads to weak and thin bones, as evidenced by a swollen face and jaw as the bones of the lower jaw weaken. It can occur in other bones also. This is similar to what occurs in reptiles when they get bone disease. You can see a picture of the swollen jaw of an Iguana with bone disease. Don’t forget to come back here because we are only just getting going.

  • Acid-base Regulation

    The pH of the bloodstream, which is a measure of acidity, is another important area of kidney physiology. The kidney regulates this acidity by excreting excessive hydrogen ions and the selective secretion and reabsorption of bicarbonate.

  • Red Blood Cell Production

    The kidneys secrete a hormone called erythropoeitin into the bloodstream. This hormone circulates to the bone marrow and stimulates it to produce red blood cells. A lack of adequate levels of this hormone will cause anemia. Toxic waste products that build up in the bloodstream decrease the life span of a typical red blood cell, further exacerbating the anemia. And, as you already learned above in hormone regulation, the fibrous bones have less bone marrow. There can even be clotting problems due to a low number of platelets.

Pathophysiology of Chronic Renal Failure

Over the course of days, weeks, or months, normal nephrons get replaced with scar tissue, and become nonfunctional. In chronic kidney disease (CKD) this scar tissue is a result of excess phosphorous. When this scar tissue occurs to approximately 75% of the nephrons the kidneys no longer have the ability to respond to the needs of the body. There is no longer any reserve, and all of the remaining nephrons are working full time. These remaining nephrons swell (called hypertrophy) to adapt to this increased workload. This allows them to adapt and selectively excrete or reabsorb important nutrients.

Eventually these remaining nephrons cannot keep up, and it leads to a buildup of nitrogenous waste products (called azotemia) in the bloodstream. The body compensates by increasing thirst, which causes PU/PD, and the waste products get flushed out of the bloodstream and into the urine.

Unfortunately, flushing out the waste products in bloodstream with excess thirst also flushes out important electrolytes and protein into the urine. This causes weight loss and weakness as the kidneys continue to deteriorate. The excess urination that occurs as the body tries to rid itself of these excess waste products can also cause dehydration.

Oral ulcers occur when bacteria in the mouth convert the extra uremic waste products to ammonia. Waste products that buildup in the bloodstream also have an effect on the bacteria in the mouth and exacerbate gingival and periodontal disease. The waste products also change the pH of the bloodstream and cause ulcers in the stomach and intestines. This causes vomiting (emesis), loss of appetite (anorexia) and weight loss. Ulcers can also be found in the mouth and tongue due to the uremia.

Hormones are affected and phosphorous builds up in the bloodstream further adding to a pet’s woes. Eventually calcium is deposited in abnormal places, and can lead to problems with many skeletal and internal organ problems. Due to sodium imbalance, hypertension (high blood pressure) can develop. Hypertension occurs in a high percentage of animals with kidney disease.

As the kidneys continue to deteriorate erythropoetin is not secreted in adequate quantity and anemia results. This anemia also makes a pet weak and adds to the anorexia that is usually present.

The nervous system is affected by all of these problems. If the uremia is severe enough hypothermia and seizures can result.

Classification

  • Acute Renal Failure (ARF)

    This is a serious form of kidney disease that commonly leads to death. The kidneys have an abrupt decrease in the GFR due to a toxin or loss of adequate blood supply (called ischemia). Many different disease processes can cause ARF, including anesthesia for any surgical procedure. That is why we give intravenous fluids (IV) to almost every surgical case.

  • Chronic Renal Failure (CRF)

    This is the most common form of kidney disease we encounter, particularly in older cats. It tends to develop more slowly than ARF, so the body has time to institute corrective factors (called homeostasis) to compensate for the problem. Unfortunately, these corrective factors tend to hide early symptoms of disease. Consequently, treatment is not initiated as soon as it might be. Again, as in many diseases we encounter, this drives home the fact that pets over 8 years of age should have annual physical exams along with blood and urine samples.

    Pets in CRF that have lost their ability to compensate for their failing kidneys can be presented to us in an acute phase, similar to ARF.

Cause

The are a multitude of causes to kidney disease. Some of these cause ARF, while others cause CRF. In some cases, ARF can progress to CRF.

Toxins

Many drugs that are used on a day to day basis can be toxic to the kidneys:

  • snake and bee venom
  • antifreeze
  • pesticides
  • herbicides
  • solvents
  • heavy metals
  • cancer chemotherapeutic agents
  • aspirin and antinflammatories
  • anesthetics
  • anti parasite drugs
  • antibiotics
  • blood pressure medication

The outcome of exposure to these toxins depends on a pet’s age, other disease processes that might be present, any medication your pet is currently taking, how long there has been an exposure and at what dose, along with the specific toxin. In some cases they are treated with supportive care like intravenous (IV) fluids. Other cases are treated with specific antidotes.

Some toxins, notably antifreeze ( 95% ethylene glycol) are catastrophic to the kidneys. Antifreeze is very sweet tasting and is readily licked by both dogs and cats if it spills on the ground when car antifreeze is changed. Ethylene glycol is converted in the liver and kidney to a toxic metabolite that changes the pH of the bloodstream and destroys the kidneys by depositing calcium oxalate crystals in the renal tubules.

It is a medical emergency and requires specific and immediate measures if the kidneys are to be saved. Unfortunately, unless a pet owner actually observes their pet licking antifreeze, they don’t bring their pet in for care until it is very ill. In this situation the prognosis is grave, and death is common. If treated within a few hours of ingestion the prognosis for recovery is much better.

Antifreeze has several distinct phases:

Stage I

This occurs during the first 12 hours after ingestion. Pets will vomit, drink and urinate excessively (PU/PD), and appear intoxicated. It is at this stage that observant owners might bring their pet in for an exam.

Stage II

This stage occurs 12-24 hours after ingestion. Symptoms are vague and pets appear to recover.

Stage III

This stage appears 24-72 hours after ingestion. Pets in this stage are severely depressed, are not eating, are vomiting, and are not producing urine. When this stage appears death is imminent.

Treatment needs to be given early in the disease to be effective. Inducing vomiting and flushing the stomach out can be very helpful if performed within 1-2 hours of ingestion of antifreeze.

Intravenous fluids and diuretics are also given to maintain normal kidney function by keeping an adequate GFR. Sodium bicarbonate is given to maintain a proper pH of the bloodstream.

Antidotes are given and can be highly effective if given early enough. In cats we give them ethyl alcohol (vodka) intravenously, and literally make them drunk. The vodka prevents the liver from converting the ethylene glycol to the toxic metabolites that destroy the renal tubules. This treatment is used in dogs also.

A better antidote, that works in dogs only, is called Antizol. It is an expensive medication, but it can literally save your dogs life.

Fortunately, the antifreeze manufacturers have added a bitter taste and we do not see this disease anywhere near as commonly.

Cancer

Cancer of the kidneys can occur even at a young age, although it is usually diagnosed in older pets. Sometimes it arises from the kidneys (primary), much more often the cancer has spread to the kidneys from a different organ (secondary or metastatic). When primary cancer does occur it is often malignant. Fortunately, primary renal tumors are rare. Cancer of the kidneys occurs more in cats than in dogs. Click here to see a case study of how we diagnosed and treated kidney cancer in a dog.

Primary

  • Lymphosarcoma- Tthis is the most common renal tumor in the cat. Cats with renal lymphoma are commonly positive for the FeLV.
  • Adenocarcinoma- The next most common renal tumor in the cat
  • Transitional cell carcinoma
  • Nephroblastoma
  • Adenoma
  • Fibroma

Secondary

Poor Perfusion

Poor perfusion means inadequate flow of blood through the kidneys, which decreases the GFR. This lack of blood flow prevents the kidneys from eliminating waste products and toxins buildup in the bloodstream. This lack of perfusion is the main pathology leading to ARF.

Heart Disease – If the heart is weak it can not pump enough blood to the kidneys to keep them properly perfused.

Drugs – Some medications can cause constriction of the artery to each kidney with a resulting lack of perfusion

Dehydration – Inadequate fluid in the circulatory system will cause poor perfusion. Dehydration is the most common cause of poor perfusion.

Cysts

They can put pressure on normal kidney tissue and compromise the filtering ability of the nephron. These tend to be found in older male cats. When there are no symptoms they are sometimes found accidentally when checking for other problems. This is called an incidental finding. When symptoms are present, they can be mild and treated easily by drainage, or there might be compromise with the normal filtering ability of the kidneys.

A specific form of cyst, called Polycystic Kidney Disease (PKD), is inherited in Persian and other long haired cats. Cysts will occur in both kidneys and will lead to CRF eventually as they enlarge and decrease functional renal tissue. The best way to make this diagnosis is with ultrasound. Ultrasound should be used on the offspring of adult cats with PKD and before any symptoms appear.

Immune System Diseases

Bacteria, viruses, cancer, and diseases of internal organs can all set off a reaction where the immune system can interfere with the ability of the kidneys to filter properly. This is sometimes called glomerulonephritis. Symptoms range from mild early in the disease to all the signs associated with kidney failure. A common method of diagnosis is excess protein in the urine (proteinuria) and a lack of protein in the bloodstream (hypoalbuminemia).We use ultrasound at our hospital to help in this diagnosis.

Treatment depends on the exact cause. It might include anti-immune system drugs, aspirin, dietary change, medication to decrease blood pressure, salt reduction, IV fluids, and diuretics.

Parasites

There are 3 main parasites that invade the urinary tract and affect the kidneys:

    1. Capillaria plica

      They are threadlike worms that affect the kidneys, bladder, and urethra. Eggs of this worm that are passed in the urine are eaten by earthworms, which are then eaten by dogs to complete the cycle. In some dogs there are no symptoms, while in others there might be blood in the urine (hematuria), difficult urinating (dysuria), or urinating small amounts (pollakuria). This parasite is diagnosed by finding the egg in a urine sample. In most cases the disease goes away by itself within 4 months, although it can be treated. Prevention of recurring cases relies upon removal of surfaces that could harbor earthworms.

    2. Capillaria feliscati

      This is an uncommon parasite in our area that invades the urinary bladder of cats. Usually there are no symptoms, and the disease routinely resolves by itself within 4 months.

3. Dioctophyma renale

This parasite resides in the kidney or abdomen near the kidneys, although they have been found in the urinary bladder, urethra, ovary, uterus, and pericardium. It causes a gradual deterioration of the kidneys.Eggs from this parasite are passed through the urine and eaten by aquatic annelids. Dogs get this parasite from eating raw fish and frogs that have eaten the aquatic annelids.Sometimes there are no symptoms until there has been significant kidney destruction. They are diagnosed by finding the egg of the parasite in abdominal fluid or in the urine. Treatment involves surgical removal of the worms from the kidneys or abdomen.They are difficult to control because the eggs can live in the environment for a long time. Dogs should be prevented from eating frogs and raw fish. It is possible for humans to get this disease from eating raw fish or frogs also.

Viruses

The FeLV and FIP can affect the kidneys. These viruses are prevalent in the cat world, and cause significant problems. We do not see these diseases commonly any more, especially FeLV. This is a testament to the use of vaccines.

Bacteria

They can ascend from the lower urinary tract and cause dysfunction in the kidneys. Leptospirosis is a specific bacteria that affects the kidneys, seen almost exclusively in dogs. Dogs get it by direct contact with infected urine through their mucous membranes. It also affects the liver.

In severe cases a dog can go into shock and rapidly die from Leptospirosis. In some cases they are sick with a fever, depression, vomiting, diarrhea, and poor appetite. There might also be muscle pain, eye problems, and respiratory problems. Most cases are chronic and might not show many symptoms.

There is a vaccine to prevent this disease which is a routine part of our DHLPP vaccine. The vaccine is highly effective in preventing this disease.

Bacteria can also cause pyelonephritis, an infection of the renal pelvis. The following bacteria are implicated:

  • E. coli
  • Staph. aureus
  • Proteus mirabalis
  • Strep. spp.
  • Klebsiella pneumonia
  • Psuedomonas aeruginosa
  • Enterobacter spp.

These bacteria usually ascend from the lower urinary tract. Occasionally they enter the kidney from the bloodstream. Their presence can cause constriction of the blood supply to the kidneys and destroy normal kidney tissue when attacked by the immune system. They can eventually lead to kidney failure. It is important to culture the urine for bacteria in any pet that is diagnosed with CKD because of the damage these bacteria can do to the urinary tract.

These bacteria can cause ARF or CRF. Symptoms include fever, depression, lack of appetite, pain, PU/PD, and weight loss. In the chronic version sometimes there are no symptoms at all. They are treated with antibiotics for a minimum of 4 weeks, along with supportive care.

Amyloid

This is the deposition of fibrous protein cells in the glomerulus that interfere with the kidneys’ ability to filter. Amyloid causes the kidneys to become small and irregular. Pets with amyloidosis have typical symptoms of kidney disease.

Most dogs are middle aged or older, and it is seen in abyssinian cats and Shar Pei dogs. It is diagnosed by proteinuria, just like the immune system diseases that affect the kidney. Amyloid can be deposited slowly allowing a long life, or it can occur rapidly leading to early death. There is no specific treatment except routine supportive care of the kidneys.

Trauma

One of the more common causes of kidney trauma is when a pet is hit by a car. These injuries can be serious and easily lead to death. Radiography is helpful in making this diagnosis, although special x-rays or ultrasound might be needed to know for sure.

This is a bruised kidney from a cat that was attacked by a dog. The bruise covers over 1/3 of the kidney. This is a fatal lesion.

Symptoms

The symptoms that occur depend mainly on how long the problem has been present and the specific reason the kidney failed in the first place. Some of the more common ones you might notice at home are:

  • Excess urinating and drinking

    This is known as polyuria/polydypsia (abbreviated PU/PD). It is by far the most consistent symptom of kidney disease. PU/PD also occurs in sugar diabetes and hyperthyroidism to name a few, so the diagnostic process needs to be followed to make an accurate diagnosis of a pet with symptoms of PU/PD. If you suspect your pet of having PU/PD you should measure how much water it drinks each day and look for a changing trend.

    In ARF there might not be any urination (called anuria) at all. This is an extreme emergency. Two of the more common causes are antifreeze poisoning and male cats with urinary tract disease that have a plugged urethra.

  • Weight loss

    Weight loss occurs due to poor appetite and the loss of protein as the kidneys attempt to flush toxins out of the body.

  • Poor appetite (anorexia)

    The buildup of toxins, electrolyte imbalances, dehydration, and even anemia are the causes of a poor appetite in kidney disease. This is one of the most common reasons pet owners bring their cats to us when renal failure is the cause. Ulcers in the mouth and stomach add to this problem. Sometimes its a wonder that cats with moderate to severe kidney disease even eat at all.

  • Weakness

    Dehydration and poor appetite add to weakness. An imbalance of a specific electrolyte called potassium adds significantly to weakness. This is the reason we sometimes add supplemental potassium to the fluids we give pets with kidney disease and also why we supplement them with oral potassium.

  • Vomiting (emesis)

    The buildup of toxins is a big cause of the vomiting. Vomiting causes further dehydration and loss of potassium, further exacerbating the problem in pets with kidney disease.

  • Seizures

    If uremia is severe enough the brain can be affected by the toxins that build up.

  • Ulcers

    If the waste products are not being eliminated adequately the buildup of toxins can cause ulceration. These ulcers are prevalent in the digestive system, especially the stomach, and might necessitate medication.

    The tip of the tongue of this cat has an ulceration due to kidney disease. Oral ulcers are due to the breakdown of urea present in saliva to ammonia by bacteria found in the mouth. There are other causes of ulceration, including trauma, biting electrical cords, poisons, and viruses.

Blindness can occur due to the high blood pressure (hypertension) that develops as a consequence of CRF. We start therapy in cats when the systolic blood pressure consistently exceeds 160 mm Hg. Diastolic blood pressure is of no clinical use in the cat.

It can be difficult to get a consistent blood pressure reading in cats due to their stressful nature at our hospital. We will repeat the test numerous times, in a calm and quite environment, to make sure the readings are accurate.

The dilated pupils from this 15 year old cat with CRF are due to blindness

Checking a cat for high blood pressure (called Hypertension) is not as simple as in a human. Specialized equipment is needed.

Diagnosis

Since the symptoms of kidney disease mimic the symptoms of other diseases a thorough approach is needed to differentiate them. In every disease we encounter we follow the tenet’s of the diagnostic approach to ensure that we make an accurate diagnosis,  and also so that we do not overlook some of the other diseases that are also encountered in pets that have renal disease. Unfortunately, it is difficult to diagnose acute renal failure early in the course of disease.

Signalment

Kidney disease can occur at any age. If it occurs at a young age we tend to think more of toxins, cysts, and trauma. The most common form of kidney disease, CRF, occurs mostly in older pets.

Several feline breeds are prone to getting CRF as they age:

  • Siamese
  • Persian
  • Abyssinian
  • Burmese
  • Maine Coon
  • Russian Blue

Certain canine breeds are also prone to CRF:

History

Kidney disease is suspected in any pet that has some of the symptoms described above, especially PU/PD. The recent administration of medication, a recent bout of a disease, the changing of antifreeze, especially in the fall , and recent administration of anesthesia, are all helpful clues. Pets that have other diseases that can affect the kidneys, notably heart disease, and hyperthyroidism, alert us to the potential for kidney disease.

Physical Exam

Symptoms noted during a physical exam depend on what caused the kidney’s to fail, how long the disease process has been present and whether a pet has the acute form or chronic form of the disease.

Physical exam findings might include:

  • Pale gums due to anemia. You can check for pale games at home. Our Learning Center shows you how.
  • Dehydration
  • Small and irregular kidneys upon abdominal palpation if CRF is present
  • Large or nodular kidneys if a cyst or cancer is present
  • Underweight
  • Enlarged lymph nodes
  • Dilated or uneven pupils
  • Weakness

This older cat has kidney disease causing low potassium (hypokelemia). If the low potassium is severe enough a cat might have this neck posture.

Diagnostic Tests

Kidney disease can only be diagnosed with appropriate tests. As a general rule, we recommend screening for kidney disease by running a blood panel and a urinalysis on all pets greater than 8 years of age. We also screen for other diseases, notably liver disease, sugar diabetes, and hyperthyroidism, on this blood panel due to their prevalence in older pets.

Lymph node biopsy

Peripheral lymph nodes can be palpated in numerous locations. They can enlarge for several reasons, one of the more important ones is cancer. If they are enlarged and significant disease process is suspected then one of them is biopsied (example to follow).

Blood Panel

An important tool in the diagnosis of kidney disease is a blood panel. We look for abnormalities in several specific tests:

CBC- Complete Blood Count

This test checks the red and white blood cells. It is not uncommon for a pet with chronic kidney disease to have anemia.

The kidneys produce a hormone called erythropoeitin that stimulates the bone marrow to produce red blood cells. Anemia occurs in kidney disease due to inadequate levels of erythropoietin, shortened survival time of red blood cells in general, bleeding in the stomach or intestines, and the effects of uremic toxins on parathyroid hormone. Pets that are dehydrated might not show anemia on a blood sample until they are rehydrated.

This dog has white gums in addition to the severe dental disease that is present. The white gums are due to anemia from CRF.

Ferret-AnemiaBloodPanel

Anemia is noted in this pet by the low HGB (Hemoglobin) and low HCT (Hematocrit). This is mild, and might be correctable at this point.

This cat has a severe anemia, and needs a blood transfusion if it is too survive

BCP (Biochemistry Panel)

There are many tests on a BCP, the following are the ones that relate to kidney disease.

BUN (Blood Urea Nitrogen)

The BUN is usually elevated in pets with kidney disease. It can also elevate in dehydrated pets and in pets with an obstructed urethra causing an inability to urinate. If a urinary obstruction is the cause of an elevated BUN, called post renal uremia, the BUN levels tend to be extremely high. If dehydration is the cause of the elevated BUN, then the values do not tend to be as high. The BUN must be interpreted in conjunction with a urine test called specific gravity to know if the BUN is elevated due to kidney disease or dehydration. Liver disease and nutrition can also influence the level of BUN.

Creatinine

It is the most accurate way to diagnose kidney disease, and is more reliable than BUN, since factors like dehydration are not as influential on creatinine as they are on BUN. This test is also a good early indicator of kidney disease even when normal, if the trend in values is increasing. This again emphasizes the importance of yearly wellness exams as your pet ages. If the creatinine is going up, even if in the normal range, we might  start treating for a kidney problem much earlier in the course of the disease.

Phosphorous
In the more advanced stages of kidney disease the phosphorous levels elevate. This is not a good prognosis.

Amylase

This is an enzyme produced by the pancreas to aid in the digestion of carbohydrates. It is excreted by the kidneys, so an excess in the bloodstream could indicate kidney disease

SDMA

Serum symmetric dimethlyarginine is a new kidney marker that might aid in early diagnosis of this malady. Increases in this test occur prior to increases in serum creatinine if a normal creatinine is considered 2.4 or less.

CRF-SevereAzotemia

This is an actual blood panel from a typical pet with severe CRF. Click on it to see the details. It shows just how advanced this problem can become in cats before owners bring their pet in for treatment. We need to catch this problem long before it gets to be this severe and there is little we can do.

Urinalysis

This is also an important tool in the diagnosis of kidney disease and another early indicator of kidney disease along with creatine. Changes in several parameters could indicate kidney disease:

Specific Gravity (S.G.)

The ability of the kidneys to dilute and concentrate the urine is an important parameter to monitor. Water has a specific gravity of 1.000. A pet with kidney failure has a specific gravity of between 1.008-1.012. A specific gravity in this abnormal range is called isosthenuria. In cats with normal kidney function, the S.G. should be greater than 1.035, in dogs it should be greater than 1.025.

This number is interpreted in conjunction with the BUN to help determine if the elevation in BUN is due to dehydration or kidney disease. To complicate things further, dehydration and kidney disease can occur simultaneously. Also, as mentioned above, liver disease, a common problem in older pets, can also be an influence. To be accurate the specific gravity should be checked immediately after obtaining a urine sample.

Protein

Excess protein in the urine, called proteinuria, is a common finding in CRF. It can also occur in glomerulonephritis, pyelonephritis and amyloidosis. There is evidence to suggest that urine protein:creatinine ratio can be a predictor of survival time. Cats with a ration < 0.4 tend to live significantly longer than cats with a ratio > 0.4.

This cat as a high ratio, indicative of kidney disease

Cells

Specific types of cells, called casts, can also be an indication of kidney disease. We interpret the casts with the specific gravity.

This cat has a normal Specific Gravity, with no protein and no casts. This is normal, it does not have kidney disease based on this urinalysis, and what we want to see on this test in cats. 

Urine Culture and Sensitivity

If pyelonephritis is suspected, or bacteria are noted in the urinalysis,  the urine should be cultured to determine which bacteria if any is present. If a bacteria is grown out then the appropriate antibiotic should be used for 4-6 weeks.

This culture grew out a Staph organism. Many urine cultures grow out a bacteria called E. Coli, which most people have heard of. The “E” stands for Escherichia. 

If an organism is grown out, many different antibiotics are tested to see which one is most effective. The “S” in this sensitivity means that this Staph. bacteria is sensitive to that antibiotic. If the bacteria was resistant to that antibiotic, there would be an “R”.

Radiography

Radiography can be very helpful in the diagnosis of kidney disease. It allows us to visualize the kidneys, check for stones in the urinary system, look for calcification that might go along with kidney disease, and also look at other organs that commonly have a problem as pets age.

These kidneys have a normal size and shape. Use this for comparison purposes as you look at the other radiographs.

This is the radiograph of a cat with normal kidney’s that is laying on its right side. The right kidney (RK) usually lies forward in the abdomen compared to the left kidney (LK). The area of the 2 kidney’s that overlaps is more whitish in nature.

This is the radiographic of a cat with renal lymphosarcoma (malignant cancer). The diseased kidney is the large white circular area in the center of this view. It is pushing the large intestine down.

Here is different cat with renal lymphosarcoma. It is a different view from the one above. Both kidneys ( K ) are involved in this cat.

Ultrasound

A very valuable tool in the diagnosis of kidney disease is ultrasound. It allows us to look at the ureters and bladder, internal anatomy of the kidney, measure kidney size, and take a biopsy for an accurate diagnosis. In many cases the use of ultrasound precludes us from having to perform an exploratory surgery.

This is an ultrasound of the right kidney, which is being measured to determine its size

Excretory Urogram

This special test, also know as an IVP (intravenous pyelogram) gives us significant information about the renal system. It has to be used carefully if ARF or CRF is suspected because it can exacerbate the problem. A radiopaque dye is injected into the bloodstream and radiographs are taken of the dye as it passes through the kidneys, ureters, and bladder.

This picture shows how the dye outlines the center of each kidney, called the renal pelvis (remember the renal pelvis in the anatomy picture at the beginning of this page?).

Laparotomy

Exploratory surgery (laparotomy) is frequently used as an aid in the diagnosis and treatment of renal disease, especially cancer. We use this option when we feel that ultrasound will not be advantageous.

The arrow points to a lump on the surface of a kidney. It was caused by cancer that spread from the stomach.

A section of the lump was biopsied during surgery to determine the cause. The tremendous blood supply to the capsule that surrounds kidneys can easily be visualized. Even though this capsular blood supply is extensive, it pales in comparison to the amount of blood that flows into and out of the kidneys through the renal artery and veins.

Three sutures were placed in the kidney capsule to control the bleeding that occurred at the biopsy site

A biopsy of a lymph node (called cranial mesenteric) located in the center of the abdomen was also obtained. This helps us determine if the cancer has spread.

cancerouskidney

This is what cancer looks like inside a kidney that has been cut open. The the left side of this open kidney the cancer goes from the 7 PM to 1 AM mark.

Treatment

Acute Renal Failure

This form of renal disease needs immediate and aggressive treatment to prevent death. In some instances we will send you to a referral center that has dialysis equipment to filter the blood of waste products while your pet’s kidneys recupterate.

Cats that have a urinary obstruction need to be unblocked immediately. If not, excess potassium in the bloodstream (hyperkalemia) can cause death to to its affects on the heart.

Any drug suspected of causing the problem is stopped immediately, and underlying problems are addressed. Fluid therapy is critical, and consists of saline and dextrose solutions initially. Fluid therapy corrects fluid and electrolyte imbalances, increases the blood flow to the kidneys, and starts the process of diuresis.

Cats need to maintain their caloric input in order to minimize the metabolism of protein for their caloric needs. Metabolizing excess of amounts of protein will increase uremia, causing a further deterioration in condition.

Pets that are still not urinating after this initial fluid therapy are given Lasix or mannitol. Excess potassium (hyperkalemia) is a common finding in ARF. If mild, fluid therapy alone should correct the problem. If severe, regular insulin and sodium bicarbonate are used. Pets with ARF are sensitive to ulcers and infections, so treatment for these problems is sometimes initiated.Ethylene glycol (antifreeze) poisoning is an example of ARF.

Pets that have heart disease are sensitive to IV fluids because excess amounts can cause an overload to the lungs called pulmonary edema. These pets pose a dilemma. If we do not give them enough fluids the kidney problem will worsen. If we give enough fluids to help flush the waste products out of the bloodstream, these same fluids might cause pulmonary edema.

This radiograph is of the chest of a normal dog. The heart (H), windpipe (W), and lungs (L) are labeled. The lungs are black because they are filled with air. This is how normal lungs look on a radiograph.

This dog has pulmonary edema. The air filled lungs are no longer black, they are white from the fluid that has built up. This is a very serious condition.

Chronic Renal Failure

This is the version of kidney disease we encounter most often. The prognosis is guarded, and depends significantly on how long the disease process has been present along with your pet’s age. Pets (usually geriatric) that have other diseases  that are common at this age can make this difficult to treat if not caught early enough.

Many pets (especially cats) that are brought to our hospital have CRF that has progressed to the point where the problem has become similar to ARF. These pets need to be hospitalized and put on intravenous fluids almost continuously to get them over this acute phase. We will closely monitor their BUN and creatinine before therapy is instituted and during hospitalization, to ascertain if their kidneys are responding to fluid therapy. If the BUN and creatinine do not drop significantly after 24-48 hours of intravenous fluids then the prognosis for recovery is poor.

Many treatments have been advocated to help minimize the symptoms of CRF (also called the uremic syndrome). None of them can cure the problem, and not all of them have proven to work, so it is important that we tailor make each pet’s therapy to its individual needs. In addition, indiscriminate use of medication to treat a perceived problem can make the kidney disease worse. This applies to almost every drug, since the kidneys are so intimatley invovled in the metabolism of drugs. The medical axiom of “first do no harm” applies directy to kidney disease.

Medical management of CRF needs to address the following:

Protein and phosphorous regulation

XS protein in the urine

High blood pressure

Anemia

Dehydration and electrolyte imbalance

Low pH in the bloodstream

Stomach and intestinal ulcers

It is sometimes easy to forget some of the more common sense remedies that are available to treat diseases, especially true in kidney disease with all the web sites and advice from people who have encountered this common problem. Fresh water should be available at all times for your cat. You should fill the water bowl at least 3 times per day to help stimulate drinking. Undue stress should also be minimized at all times also.

Diet

Pets with CRF need to be fed a diet that has limited amount of high quality protein. Less protein in the diet leads to less work the kidneys have to perform by removing the nitrogenous waste products that are the end result of protein metabolism. Protein is vital to all bodily functions and can not be indiscriminately limited. As a matter of fact, if protein restriction is not implemented carefully it can make the uremic syndrome worse.

High quality protein means that it contains more essential amino acids, which are those the body cannot produce and must be obtained in the diet. The commercial food that we recommend for kidney disease is called K/D©. It is made by Hills© and is available only from a veterinarian because it is used to treat a specific disease. In addition to high quality protein it also has less phosphorous and sodium.

This food is the gold standard for CRF, and has been used successfully for decades to slow down the progression of CRF and give your pet a very good quality of life. If your older cat has arthritis, which is not uncommon, using the K/D with mobility will help for both problems.

Most cats take readily to K/D, although it can sometimes be difficult to change the diet on an older cat. Many of the cats are eating poorly and have already lost weight due to the kidney disease, so we don’t want to add to their problem by feeding a diet they won’t eat. Mixing this new food in partially with the regular diet and heating it up a little (for the canned food) in the microwave helps. adding a small amount of a tasty fluid like clam juice can make it taste better.

The use of appetite stimulants, which you will learn about below, are benificial here. It is important to keep your cat eating so that it does not lose muscle mass.

Water soluble vitamins (ex.- B-complex vitamins) are easily depleted in a pet that has PU/PD. Supplementation can be helpful.

Do not use foods that are lableled “for urinary health”. They are treating a different problem called FLUTD. These foods change the pH of the bloodstream in a way that is detrimental to the kidneys.

Phosphorous lowering medication

Pets with CRF might have an increase in their phosphorous levels as the disease progresses. This excess phosphorous can add to the anemia that is common with CRF. It will also dramatically influence calcium metabolism in the body through a hormone called parathyroid hormone. The end result will be painful calcium deposits in the bones and internal organs, including the kidneys. This will also add to the scarring and add to the progression of CKD.

As already mentioned, K/D©is restricted in phosphorous, and should be used in combination with phosphorous binding medication. The phosphorus binding medication we use, which always needs to be given with food, is called Epakatin by Vetoquinol©.

Potassium increasing medication

Pets with CRF will have a decrease in their potassium levels as the disease progresses. This does not always show up on a blood panel. Using oral supplements and adding additional potassium to fluids helps counteract this problem. Oral potassium is called Renal K+©, and it comes in a paste for easier administration.

Urine protein reducing medication

Reducing protein in the urine is believed to help slow down the progression of the disease. ACE (Angiotensin Converting Enzyme) inhibitors (ex- Enalapril) or ARB’s (Angiotensin Receptor Blockers) are used when the urine protein:creatine ratio is greater than 0.5 in the dog and greater than 0.4 in the cat. These drugs are given for 30 days and then the urine is checked to see if there is either a 50% reduction from the original test, or if the ratio is below 0.5 in the dog and 0.4 in the cat.

Anemia fighting medication- Darbopentin

One of the long term affects of CRF is anemia due to a lack of erythropoietin secretion from the kidneys. This hormone can be supplemented to help minimize anemia.

Fluids

One of the most important treatments for CRF is the administration of supplemental fluids. Whenever we tell people their pet with kidney disease needs fluids they commonly respond “its OK, he/she already drinks a lot of water”. Unfortunately, this excess drinking of water is a result of kidney disease, and not a sign that the pet is drinking adequate amounts of water. Cats in particular are not good drinkers, and need additional water to what they are already drinking.

If your pet is hospitalized we will give them intravenously (IV) because of greater effectiveness and accuracy. If your pet responds to IV fluids during its hospitalization we will initiate the use of subcutaneous (SQ.) fluids at home on a daily basis.

This area of home treatment is so important that we have devoted a complete page to its use. Please click here to learn about the proper technique, then return to this section for more treatment options.

Most cats with CRF should receive between 50 ml and 100 ml of SQ fluids at least several times per week. As the problem progresses it will become necessary to give this fluid on a daily basis. We commonly add B-complex vitamins to the fluid bag since these water soluble vitamins are excreted the more we give supplemental fluids. Feeding a food designed for kidney disease like K/D will also help minimize the depletion of water soluble vitamins.

Blood pressure medications

Hypertension is a common occurrence as the disease progresses. Any systemic blood pressure of 160 mm or more should be treated. Blood pressure lowering medications like Norvasc (calcium channel blocker) and Enalapril (ACE ihnibitor) will help counteract this problem. All cats initially diagnosed with CRF should have a blood pressure taken. It should be rechecked at least every 6 months.

Some cats might respond to ACE inhibitors to decrease the protein in their urine. Further studies are needed in this area to determine efficacy.

Anti-ulcer medication

Some cats with CRF don’t eat well because of nausea due to excess hormone secretion in the stomach. Tagamet or famotidine is used to counteract this problem. If we suspect an ulcer in the stomach due to the toxins that have built up we will use Tagamet also.

Anti-vomiting medication

Vomiting is a common problem in pets with CRF. It occurs as a result of uremic toxin buildup in the bloodstream and alterations in hormones that regulate gastric secretions. Vomiting will cause dehydration, leading to a decreased flow of blood to the kidneys (decreased GFR) and an increase in azotemia. We use a drug called Reglan  or Cerenia to alleviate vomiting symptoms.

Antibiotics

Animals weakend by kidney disease are more susceptible to infection. These pets are commonly older and have significant dental disease. Antibiotics help them fight off infections. The antibiotic dose might have to be adjusted since many of them are removed from the body by the kidneys. Pets with CKD commonly have urinary tract infections due to bacteria, so a urine culture and sensitivity is needed in these pets to see if this problem is present.

Anti vomiting medication

Pets with CKD are commonly vomiting. This is a sign of how sick they are, and it also precludes them from getting proper nutrition, which is crucial in the treatment. Putting these pets on Cerenia, a very effective anti-vomiting medication, is necessary if your pet is vomiting. There is an injectible form of this drug used in an acute case, and an oral version for long term use.

Appetite stimulant medication

Pets with CKD do not eat well for many reasons. Getting them to eat is crucial, and some of them need appetite stimulants. The most effect ones we have found are Periactin and Mirtazapine. Mirtazapine comes in a topical version if you cat is not eating well.

Probiotics

 This supplement digests non-protein nitrogen in the intestines, mininizes BUN and creatinine levels, so there is less work for a diseased kidney.

Feeding Tubes

This overlooked and effective treatment helps dramatically for cats with CKD that are not eating well, are vomiting, and are difficult to medicate orally and with SQ fluids. We have a detailed page on feeding tubes.

Miscellaneous treatments

There are other supplements and medications used in CRF that might be of some benefit, although this is unproven. As long as they do not cause the problem to worsen they might be worth trying. Anabolic steroids– They are also used in older pets for arthritis and appetite stimulation with good success. They might help counteract the affects of anemia, although this can not be relied upon. DecaDurabolin  is the one we used most frequently. Drugs like this are no longer readily available. Calcitriol– It is postulated (there is no proof) that some of the symptoms of CRF are the result of elevated levels of parathyroid hormone. This hormone helps in the regulation of calcium levels in the bloodstream. By adding low doses of the hormone calcitrol the parathyroid hormone will be suppressed, and your pet might feel better. The phosphorous level must be controlled, and the calcium level monitored closely, if one of our doctors decides to use this modality.

Kidney Transplantation

At some select veterinary universities (University of Georgia) a new kidney can be transplanted into a cat. This does not cure the problem, it is a help in controlling the problem in cats that are losing weight and are anemic in spite of medical therapy. This specialized surgery can cost upwards of $10,000. Your cat has to be kept on immunosuppressive therapy (cyclosporine and prednisone) the rest of its life, and the donor cat has to be adopted. Complications can occur, especially rejection of the new kidney.

This is Skipper with his wonderful mom in for special testing before he goes to Georgia for his kidney transplant

Skipper2

This is a picture of him during the surgery. The organs are labeled below for your understanding. 

The old, swollen, and diseased kidneys are labeled. The new kidney is circled

Skipper1

Skipper returned several months later feeling much better, and with his new brother!

Prognosis

Pets presented with renal disease, whether ARF or CRF, carry a guarded prognosis. It can be successfully controlled in most circumstances, especially if the diagnosis is made early enough. We talked about this at the beginning of this page by recommending that all cats at 8 years of age be fed Hill’s K/D Early Support.

If your pet is hospitalized with CRF we will closely monitor its blood panel, paying special attention to BUN, creatinine, and phosphorous. If the excess levels of these tests decrease dramatically during hospitalization, and your pet improves clinically, then the use of K/D food, medications and SQ fluids at home are usually advantageous.

All pets that have been diagnosed with CRF should have a blood panel, a urinalysis, blood pressure check, and physical exam performed every 3-6 months. This disease will progress, and other diseases might present themselves, so this type of monitoring is crucial for a good quality of life.

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Cognitive Dysfunction Syndrome (CDS)

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Growing old is a natural process and a fact of life, for all of us, including our four-legged family members. This is especially prevalent in dogs since they age faster than us humanoids. Family members will probably be the first to notice the subtle changes of Cognitive Dysfunction Syndrome or CDS. It may be more than just “getting old.” Dogs with CDS may show signs of confusion, forgetfulness, less responsiveness, and/or other various behavioral changes that are not a normal part of aging. These subtle signs might not be exhibited in the examination room so we may not see them during an examination.


Cause

CDS is believed to be caused by physiological and chemical changes in the brain of aging dogs that affect brain function. These may include accumulation of B-amyloid, declining neurotransmitter activities, or increased activity of monoamine oxidase-B, an enzyme that may catalyze the metabolism of dopamine.1

In MRI (Magnetic Resonance Imaging) studies of the head, images show black and white cross-section “slices” of the brain. In MRI studies of older dogs with CDS, we see changes when compared to MRI studies of younger dogs. In the images above, note the ventricular space enlargement (V arrows) and hippocampus tissue shrinkage (H arrows) seen in the older dog image on the left, compared to the younger dog image on the right.1


Symptoms


Disorientation
(not due to vision or hearing loss)
Wanders aimlessly
Appears lost or confused in familiar surroundings such as the house or yard
Gets “stuck” in corners or under or behind furniture
Stares into space or at walls
Has difficulty finding the door
Stands at the wrong door to go outside
Stands at the “hinge” (wrong) side of the door
Does not recognize familiar people
Does not respond to verbal cues or their name
Appears to forget the reason for going outside
Activity and Sleep Sleeps more in a 24-hour day (overall)
Sleeps less during the night
Decrease in purposeful activity in a 24-hour day
Increase in aimless activity (such as wandering, and pacing) in a 24-hour day
Housetraining (for dogs previously housetrained) Has “accidents” (urinates or defecates) indoors
Has “accidents” indoors in view of family members
Has “accidents” indoors soon after being outside
Signals less to go outside (for dogs who previously signaled/asked to go outside)
Interaction with Family Members Solicits attention less
Less likely to stand/lie for petting (walks away)
Less enthusiasm upon greeting
No longer greets family members (once the dog has realized that family members have arrived)

Diagnosis

Since a biopsy of the brain is not usually a diagnostic option, a presumptive diagnosis can be made when there are clinical signs consistent with CDS and the absence of any underlying medical causes.

For a suspected case of CDS, as for any behavior problem, a history, physical examination, and diagnostic tests are needed to rule out the presence of any medical conditions that might affect behavior. These might include diseases of the internal organs, especially liver, kidney, and heart.

Additionally, primary and secondary behavioral problems need to be ruled out such as separation anxiety, noise phobias, or housesoiling.

Medical Conditions with Behavioral Components:

Medical condition Associated clinical signs

Sensory dysfunction

(loss of sight, hearing, smell)

Increased irritability, fear or aggression
Decreased appetite
Increased vocalization
Changes in sleep-wake cycle
Disorientation
Decrease in greeting behavior
Inattentive, decreased responsiveness to verbal commands

Urinary tract disease
Renal disease
Lower urinary tract infection

Incontinence, loss of housetraining
polyuria (urinating more)
polyphagia (eating more)
stranguria (painful urination, straining to urinate)
pollakiuria (urinating more frequently)

Osteoarthritis

Weakness, reduced mobility and activity
Increased pain, irritability
Possibly inappropriate elimination

Hypothyroidism

Decrease in activity
Increased irritability or aggression
Reduced tolerance to cold

Hyperadrenocorticism
Cushing’s disease

Polyphagia (eating more), polyuria (urinating more), restlessness
Decreased social interaction, responsiveness to commands and greeting behavior
Reduced activity
Loss of housetraining
Disrupted sleep-wake patterns

Neurological disorders

(primary or secondary
intracranial neoplasia)

Changes in sleep patterns, eating habits, housetraining, aggression, docility

To obtain a complete medical and behavioral history, we may ask many questions because signs of CDS may be subtle and not be exhibited in the examination room during during an examination. A printable Senior Dog Behavior History Form to aid in diagnosis of CDS is available by clicking here.

We will perform a thorough physical examination. In addition, a brief neurological examination will include assessment of cranial nerves, evaluation of postural reactions, especially conscious proprioception, and evaluation of the perineal reflex to assess sphincter function.

Typical diagnostic tests would include a serum chemistry profile, complete blood count (CBC), and urinalysis. Additional tests may be warranted based on the patient’s history and physical examination results.

Another method of diagnosis is response to therapy. If your dog improves when treated then there is a good chance he has this disease.


Treatment

Anipryl® is a medication, in tablet form, generally given once a day. We will recommend the appropriate dose for each individual patient. You can learn much more about it by clicking on the link.


Additional Reading:

1. Cognitive Dysfunction Syndrome and Other Geriatric Behavior Problems; CE Advisor a supplement to Veterinary Medicine, Feb 1999.[view PDF format].

2. Controlling CDS with Anipryl®: Post Approval Field Research Results from Private Hospitals in the US; Pfizer Animal Health Technical Bulletin, Dec 2000. [view PDF format]


You will need the Adobe Acrobat Reader to view and print the bulletins and forms, which are in PDF format. If you already have Acrobat® Reader, you can immediately download and print the documents. If you need a copy of the Adobe® Acrobat® Reader®, click the icon below to download it free of charge from Adobe®.


References:

  1. Adding New Science to the Practice of Medicine – Senior Dog Health, canine Cognitive Dysfunction Syndrome and anipryl® Senior Health Care advisor Program, Pfizer animal Health
  2. Campbell, S; Controlling CDS with anipryl®: Post approval Field Research Results from Private Hospitals in the US; Pfizer animal Health Technical Bulletin, Dec 2000.

Developed for Long Beach Animal Hospital, by Glenna M Gobar DVM, MPVM, MS, courtesy of Pfizer Animal Health; Sept 2001

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