LBAH Informational Articles

Seizures (Epilepsy)

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 have epilepsy, so we will emphasize this disorder when discussing treatment.

We have a few short videos on this page, you will need QuickTime from www.apple.com to view them

Here are some medical terms we will be using in this page:

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 the problem 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.

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 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.

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.
  • PoisonsThe 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
    • 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.

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

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.

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

.

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

Blood Panel and Urinalysis They 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 is 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.

They 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)

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.

The adrenal glands are small, so click on photos to enlarge them.


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. 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.

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. 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. 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.

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. 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).

Cushing's-FlowChart

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

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

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 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.

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.

Arrhythmia’s are usually diagnosed with an electrocardiogram (ECG). This is a lead II ECG on a pet with a heart rate of 106 beats per minute.

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.

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

  2. 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.

  3. 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
  4. 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 very comprehensive. This high cholesterol alerts us to keep hypothyroidism in our tentative diagnosis list. Notice the elevated amylase and lipase tests above the cholesterol test? These are indicative of pancreatitis, which is exactly what this dog has.

    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 routine thyroid test by RIa (radioimmunoassay) is at the high end of normal. This dog most assuredly does not have hypothyroidism.

    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.

    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

  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 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 Renal Failure)

One of the more common conditions encountered in pets, especially as they age, is kidney (renal) disease. This disease is particularly prevalent in older cats, and is called chronic kidney disease ( also known as chronic renal failure (CRF).

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.

The kidneys are a very important organ, and do much more than just filter waste products out of the bloodstream. When a pet has chronic kidney disease there are many issues that need to be addressed for a successful outcome to treat. 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
  • High blood pressure
  • Anemia
  • Dehydration and electrolyte imbalance
  • Low pH in the bloodstream
  • Stomach and intestinal ulcers

This page describing kidney disease is very thorough. We have a summary page on kidney disease if that better suits your needs.

Cats 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 diseasedental diseasesugar diabetes (diabetes mellitus), and 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.

This is the kidney from a cat, with the fat that normally surrounds it removed. It lies in a depression in the abdomen called the retroperitoneal area. 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.

This is how it normally resides, protected by fat in the abdomen

OLYMPUS DIGITAL CAMERA

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 renal failure.

This is how it looks in a real kidney from a cat

This is a kidney, turned sideways compared 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.

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. It affords protection to this vital organ.

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. When this 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.

This disease 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.

Dioctophyma renale

  1. 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.

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, including a doppler ultrasound.

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.

    Anemia is noted in this pet by the low HGB (Hemoglobin) and low HCT (Hematocrit). This is mild, it can be much more severe than this.

    Ferret-AnemiaBloodPanel

  • 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 a very 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.

  • h4>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.

  • Red Blood Cells

    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.

    This is an actual blood panel from a typical pet with severe CRF. The 3 most important tests on this panel are highlighted in yellow, along with their normal values on the right.

    This cat is even worse!  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.

    CRF-SevereAzotemia

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.

Cells

Specific types of cells, called casts, can also be an indication of kidney disease.

This urine sample is from the cat with the blood sample shown above. The S.G. is very low, and since this cat has a high BUN, the problem is most likely due to CRF. Fortunately for this cat there are no other serious abnormalities on this urine sample.

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.

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 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.

These ultrasound pictures are from the first cat above with the enlarged kidneys. The first picture shows a normal right kidney. Its measurements are 2.3 cm by 3.6 cm.

The 2nd image shows the large and cancerous kidney, measuring 4.6 cm by 7.3 cm. A biopsy was taken from this kidney to confirm the diagnosis of renal lymphosarcoma.

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.

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

cancerouskidney

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.

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.

It is better to have a cat eat anything than to have a cat that won’t eat anything, even if that diet is made to help the kidneys. Sometimes the best we ca hope for is to mix some K/D in with whatever food it ate prior to its diagnosis of CRF.

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.

Antacid type medications will bind to the phosphorous and keep the level in the bloodstream down. We use amphogel© because it is readily available over the counter, it is a liquid, and cats tolerate it well. As already mentioned, K/D©is restricted in phosphorous, and should be used in combination with phosphorous binding medication.

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 Tumil-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 2 months 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. 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.

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. Appetite stimulants– They are used in older pets in general so their use in CRF might be helpful. Periactin and Mirtazapine are common appetite stimulants. 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 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. Azodyl- Azodyl is a patented formulation of naturally-occurring beneficial bacteria (Kibow Biotics®) that can be used to support renal health Epakitin– Epakitin is a chitosan, calcium carbonate, lactose and hydrolyzed soy protein based nutritional supplement/food supplement.

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

Skipper returned several months later feeling much better and with his new brother!

Skipper1

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. 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 medications and SQ. fluids at home are usually advantageous.

All pets that have been diagnosed with CRF should have a blood panel, a urinalysis, 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)

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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Demodectic Mange

Demodectic mange (Demodecosis) is caused by an external parasite that is also present in low numbers on healthy animals, including people. Whether or not a pet shows symptoms of this disease depends primarily on their immune status. Since there is no easy test to determine immune status, it is impossible to predict which pets will get this disease, or how well a pet will heal if it shows symptoms of demodex. 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, allergies, Cushing’s or Sarcoptic mange can look like they have demodex.

Cause

Demodectic mange is caused by a mite, a microscopic ectoparasite that infects the hair follicles. Most pups pick up these mites from their mother when they are nursing, and do not normally cause any problems. It is those pets that have an inadequate immune system that develop this disease.

The parasite is cigar shaped and has several pairs of legs. It is only visible under a microscope. This is a picture of one that is laying on its back, its legs are towards the right, and its mouth is at the far right.

5075

There are underlying causes that can weaken the immune system and make a pet more susceptible to this disease. These include the chronic use of cortisone, Cushing’s disease, heartworm, cancer, and hypothyroidism.

Adult dogs that have demodex take longer to treat than young dogs.

Symptoms

One of the most common symptoms of this disease is small patches of hair loss (alopecia), towards the front of the body initially, with the ability to affect the whole body. When it is present in adult dogs it commonly affects the feet.

If a pet has only a few small patches of alopecia the disease is classified as localized. If it has spread throughout the body it is classified as generalized. Most pets that have demodectic mange are young, which is a big aid in the diagnostic process.

The patch of hair missing on this pups face is caused by Demodex, and is an example of the localized classification.

Face

This is an example of generalized demodecosis on the chest and front legs. This is a serious condition and carries a guarded prognosis.

Chest

Diagnosis

The primary way to diagnose demodectic mange is to do a skin scraping where the patches of alopecia occur. The fortunate thing about demodex is the ease of diagnosis in most dogs (Shar Pei’s can be an exception). In most cases the mites are easy to find under the microscope, and if your pet is diagnosed as having this disease, one of our staff members will show them to you under the microscope. A positive skin scraping of large numbers of demodex mites, along with alopecia (remember demodex is naturally found in the skin also), is verification of demodectic mange and necessitates treatment.

Treatment

We are fortunate to have several medications at our disposal to treat demodecosis. Unfortunately, one of the most common medications called Mitaban, is no longer available. These medications have proven to be highly effective, and have saved many pets from suffering, and even euthanasia. Sometimes the most we can hope for is to control the problem, not cure it. Treatment duration needs to based on skin scrapings, not just the appearance of the skin. A skin that looks like it is healed can still harbor demodex mites. This is especially true for adult dogs with feet lesions.

Unfortunately, due to the fact that the immune system is paramount in whether or not your pet gets this disease, no guarantee can be made that these medications will work. No matter which form of demodex is treated, several ancillary issues need to be addressed. Your pet needs to be on optimum nutrition, stay current on vaccines, and be free of internal parasites (worms). Like any disease process, the psychological needs of your pet need to be met, which includes plenty of exercise, TLC, and access to fresh water at all times. Other skin conditions like allergies can occur simultaneously, and need to be treated also.

  1. Localized Treatment

    Bathing with an antibacterial shampoo is the first step in therapy. This loosens up scales, removes oily discharges, and decreases the secondary bacterial infection that is usually present.

    Localized demodex was historically treated with a medication called Goodwinol. It is a creme that is rubbed into the areas of alopecia once daily. This rubbing initially causes more hair to fall out, but within 1-3 weeks the problem usually goes away. If more areas of alopecia appear during this time they should be treated with Goodwinol and brought to the attention of one of our doctors during recheck exams.

    Another treatment for localized demodex involves the use of Mitaban mixed into olive oil. This mixture is applied on the areas of hair loss daily. It is possible for localized demodex to progress to generalized demodex even if it is treated. Mitaban is no longer available.

    Localized demodex might even resolve without any treatment.

  2. Generalized Treatment

    Generalized demodex is treated with a combination of medications and modalities. It is important to understand that treatment may take 2-3 months to be effective. The hair is usually clipped to allow the topical medication easy access to the skin, which makes it substantially more effective. Secondary pyoderma (skin infection) is usually present also, so your pet is put on oral antibiotics for several weeks to months.

    The main drug used to treat generalized demodex in the past is called Mitaban. Unfortunately, Upjohn no longer makes it, so we have to use substitutes. Mitaban has to be used precisely by label instructions. Since it is difficult for people to do this properly in their homes, we treat most pets in our hospital. Pets are dipped once per week, in between these dips your pet should not be bathed. We continue dipping until successive skin scrapings are negative for the mites.

    Mitaban2860

    If Mitaban does not work there are other medications that are used with varying success to cure the problem. These include oral Ivermectin and Milbemycin (Interceptor). Side effects like excess salivation, incoordination, even coma and death are possible, so they must be used judisciously. They should not be given to Collies, Shelties, australian shepherds, or dogs that are positive for heartworm. There can be no guarantee that they will work, especially in a disease that is so closely associated with the immune system. Spaying infected females is helpful.

    Promeris, a flea and tick treatment is highly effective. Even though Pfizer no longer makes it our hospital has a supply of it.

    Advantage Mulit can also be used to treat generalized demodecosis.

Prevention

Pets that have this disease should not be bred. Otherwise, it is difficult to predict just what pets will get this problem.

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Diabetes Mellitus (Sugar Diabetes)

FRUThis page describing diabetes mellitus (DM) is very thorough and will require some study if you want to understand it fully. There is a different kind of diabetes, called diabetes insipidus, which is not the same disease. In general, when most people say a pet or a person has diabetes, or  if they also say sugar diabetes, they are refurring to diabetes mellitus.

Sugar diabetes, more correctly know as diabetes mellitus (DM), is a complex disease that is difficult to control, particularly in cats. Proper treatment requires a commitment on your part, usually for the life of your pet. It is well worth the effot in most cases because response to treatment is usually quite rewarding.

By definition, DM is a persistent hyperglycemia and glycosuria due to an absolute or relative insulin deficiency. By the time you are done with this page you will understand what all of this means.

You will also learn that some of the parameters of DM in animals are similar to humans, and many parameters are not, so be careful of extrapolating any experience you have between the two. DM can occur in many different species like birds and Guinea Pigs, although it is most commonly diagnosed in dogs, and especially cats.

Obesity is a big reason pets get DM. Fat is not just fat, it causes inflammation, leads to the rise of insulin resistance, which means your pet gets DM and does not respond well to insulin treatment. Most obese cats are prone to be what is called prediabetic. It all has to due with a hormone called amylin elevated in the bloodstream of overweight cats.

You can go far in preventing DM by keeping your pet at a normal weight, and feeding your cat a food that is higher in protein and lower in carbohydrates. Routine exams, that include blood panels and urinalyses that both monitor glucose, are important as your pet ages.

It will help if you learn these medical words because they will be used on this page:


Normal Physiology

The ability to use a food source for energy is critical to the success of any species, therefore nature has very sophisticated mechanisms to regulate this process. These mechanisms are extremely complex, and only those mechanisms that relate to diabetes mellitus will be summarized for the sake of simplicity.

In response to a decreasing blood glucose level the appetite center in the brain is stimulated and hunger ensues. A meal is then eaten, which consists of fats, carbohydrates, and proteins, in different percentages. When these fats, carbohydrates, and proteins are broken down by the digestive system and absorbed into the bloodstream, they are used by the body for various functions. The main function of the carbohydrates is eventual conversion to an energy source in the form of glucose, the primary energy source for all cells in the body. Some of this glucose is stored in the liver in the form of glycogen, which is released and converted back to glucose when cells need energy in-between meals.

Carbohydrates can be complex or simple. Complex ones are bread and pasta, simple ones are lactose (the carbohydrate in milk). When these carbohydrates are absorbed in the bloodstream through the intestines they are converted to glucose by the liver. The simple ones, like lactose, are rapidly converted and will immediately raise the blood glucose level. The more complex carbohydrates take longer to be metabolized to glucose by the liver, as a result they raise the blood glucose level more slowly. This point becomes important when treating both hyperglycemia and hypoglycemia.

Once in the bloodstream the glucose that circulates throughout the body is available for use by all cells as their primary energy source. These individual cells cannot absorb this glucose that passes by in the bloodstream unless the hormone insulin is circulating in the bloodstream at the same time. Insulin causes a chemical reaction in the cell wall that allows the glucose to enter the cell. The only cells in the body that do not need insulin to absorb glucose are specific brain cells.

Insulin originates in a group of cells called the islets of langerhams that are located in the pancreas. Insulin comes from the beta cells in the islets. It is secreted into the bloodstream in response to an increase in glucose in the bloodstream, a normal occurrence after a meal is eaten. The higher the glucose level the greater the amount of insulin secreted. Since the absorption of simple carbohydrates will cause a more rapid increase in blood glucose there will be a more rapid increase in insulin secreted. The complex carbohydrates will cause a more gradual rise in the insulin level.  This fact becomes important in feeding a diabetic patient.

The normal physiology is even more complex. Insulin also has a large effect on fat and protein metabolism. In addition, the pancreas also secretes a hormone called glucagon in response to a decreasing blood glucose level. Glucagon originates from the alpha cells in the islets, and its role is to help the liver convert glycogen back to glucose. As can be expected, glucagon will increase the blood glucose level, and counteracts the blood glucose lowering effects of insulin. Insulin and glucagon work in a negative feedback loop that allows for a very refined system to keep the blood glucose level at an optimal level for the energy requirements of each individual cell. The liver is a major part of this loop, acting as a blood glucose buffer to keep the blood glucose at optimum levels. This is a highly refined process that is fine tuned over thousands of years and works extremely well.

In general, brain cells do not need insulin to utilize glucose. A specific area of the brain, called the appetite center (in the hypothalamus), monitors the amount of glucose that circulates in the bloodstream. The lower the blood glucose level in the cells in the appetite center the greater the appetite. Unlike most of the brain cells, the ability of glucose to enter the cells of the appetite center is dependent upon insulin. In diabetes mellitus, with its lack of adequate insulin in the bloodstream, these appetite center cells don’t monitor glucose levels properly, thinking the blood glucose is low. As a result, the pet develops polyphagia to correct for this perceived problem. The additional food that is then eaten further increases the blood glucose level.

The pancreas does more than secrete insulin and glucagon into the bloodstream. It is the primary source of enzymes that are secreted into the small intestines (not bloodstream this time). These enzymes are secreted in response to the presence of food in the digestive tract, and are the primary way that many nutrients are broken down and absorbed by the intestines into the bloodstream. The way these energy sources are acted upon by the enzymes, and how they are eventually utilized by the liver, are also factors that effect the blood glucose level.

To further complicate the picture, epinephrine (adrenaline), cortisol (cortisone) and growth hormone also influence the blood glucose level.

This is a picture of the pancreas of a cat. It is adjacent to the beginning of the small intestine called the duodenum. The pancreas is the pinkish tissue directly under the cylindrical duodenum. For such a small organ it has an important job.

Now that you are an expert at normal physiology, lets learn what happens when the normal mechanisms described above go wrong. This is called pathophysiology. What causes this pathophysiology, leading to a lack of insulin production by the pancreas? It is multi-factorial, and includes:

  • Genetic predisposition
  • Infection
  • Toxins
  • Inflammation

Obesity and a lack of physical activity are predisposing factors, especially in cats.

Pathophysiology

The relative lack of insulin causes the blood glucose to go abnormally high. Normal blood glucose in a dog or cat varies from 80 to 150, but can temporarily go much higher (300-500 or more) in stressful situations. When the blood glucose is consistently high, as seen in diabetes mellitus, several negative effects occur.

Inadequate insulin levels force the cell to perform its functions with alternative sources of energy besides glucose. This causes problems for the organ that is made up of these cells, and eventually will lead to significant disease and the complications that occur in untreated diabetes mellitus.

The cells of the body (except most brain cells) are deprived of their primary source of energy. This means they do not function at optimum efficiency. Since they are starved of glucose they need to rely on other sources of energy, namely fat and amino acids. These are not as good an energy source as glucose in the long run.

To utilize amino acids as an energy source the body needs to break down protein. A large part of this conversion occurs in the protein in muscles cells. As this conversion from protein to amino acids progresses the body loses its muscle mass and weight loss occurs.

Metabolism of fat as an energy source is a normal response when cells do not receive adequate glucose for their energy. In the short term this process is highly advantageous. Fat has twice as much calories as proteins and carbohydrates, so it is a concentrated source of energy in the short run. If the fat metabolism process goes on for a prolonged period of time it becomes detrimental, and leads to the buildup of byproducts from fat metabolism. The main byproduct is a compound called ketones.

The ketones that build up in this process change the pH of the blood, further dehydrate a pet, interfere with other metabolic processes, and cause fatty infiltration of the liver. Ketones also cause vomiting, which leads to further inappetance and additional dehydration and electrolyte imbalance. Further inappetance causes the cells to use even more fat as an energy source, causing an uncontrollable spiral, and sometimes even death. Any diabetic pet presented with ketones in its urine is a medical emergency. These pets have what are termed diabetic ketoacidosis, abbreviated as DKA.

In addition to the liver, the kidneys are another important organ in this disease. The primary role of the kidneys is to filter the blood. As the blood passes through the kidney filters essential nutrients are returned to the bloodstream and waste products are excreted through the urinary system. Glucose is one of the many molecules that is returned to the bloodstream after it has passed through the kidney filters. Once the glucose exceeds 200 mg per deciliter (this varies by species, cats tend to be higher) in the bloodstream though, the kidneys can no longer selectively return all of this glucose back into the bloodstream. This is called “exceeding the renal threshold”, and is a very important part of diabetes mellitus.

As a result, glucose spills into the urinary tract and bladder in excessive quantities. Since glucose attracts water (called the osmotic effect) it pulls fluid out of the pet and causes polyuria. To compensate for this excess urination the pet drinks more water, and now has polydypsia. It now has the symptoms we abbreviate as PU/PD. Eventually it causes dehydration when the pet can’t drink enough water to keep up with the increased urination. In addition, the excess urination pulls important electrolytes out of the bloodstream like sodium and potassium, which leads to lethargy and weakness. The loss of glucose also depletes the body of its primary energy source, so additional weight loss occurs. To further add to a diabetic pet’s woes, the excess glucose that builds up in the bladder feeds bacteria that can cause a urinary tract infection.

Why the pancreas stops secreting adequate levels of insulin is a mystery. There is a strong correlation for diabetes mellitus to occur in cats that previously had an episode of pancreatitis. This makes sense because the pancreas is the source of insulin. Yet, many cats that have diabetes mellitus had no apparent pancreatitis in the past. In some pets the immune system attacks the beta cells in the islets and deposits a compound called amyloid which, makes the beta cells unable to secrete insulin. This amyloid, which contains a protein called amylin, is thought to play a significant role in non-insulin dependent diabetes (your will learn about this soon) because amylin is toxic to the cells in the islets of langerhams.

Another factor involved in non-insulin dependent diabetes is peripheral insulin resistance. This resistance plays a significant role in obese pets, which is a major predisposing role in the development of insulin. Genetics is also involved-genetics cannot be controlled, but obesity can.

Elevated levels of thyroxine, which occurs in feline hyperthyroidism, can also be a factor in insulin resistance.

So what does all of this mean? To summarize all of this pathophysiology:

    • Peripheral insulin resistance, due to obesity and/or the protein amylin found in amyloid, causes chronic stimulation of insulin production in the pancreatic beta cells.
    • Impaired insulin secretion causes insulin and amylin to accumulate in beta cells in the pancreas.
    • The high levels of amylin in the beta cells allows amyloid to deposit, further disrupting the ability of these cells to produce and regulate insulin. As the problem progresses non-insulin dependent diabetes eventually progresses, and at some point in time, the symptoms of diabetes mellitus appear.
      The pancreas can get a tumor called an insulinoma. In this case the pancreas secretes too much insulin and the blood glucose hovers at dangerously low levels. This problem is rare in most animals except for the ferret

Classification

Most people are familiar with the classification scheme used in human medicine. Even though the disease is similar in people and pets, the human classification scheme does not always correlate with diabetes mellitus in cats. Differentiating between Type I and Type II in cats can be difficult.

  • Type I

    Has similarities to insulin dependent or juvenile onset diabetes mellitus. Most commonly occurs in middle aged cats. Insulin is needed to treat the problem. This is also known as insulin dependent diabetes mellitus (IDDM).

  • Type II

    Similar to adult onset or non-insulin dependent in humans. Obesity is a significant risk factor. Insulin is not needed in all cases. Type II cats can become Type I cats when exposed to significant stress. Fortunately, when the stress is resolved they can revert back to Type II. This is also known as non-insulin dependent diabetes mellitus (NIDDM).

    Diabetes can occur secondary to other problems. Some of these problems include hormone imbalances and reactions to medications. A medication called Ovaban, a hormone used to treat numerous cat ailments, can cause diabetes if used excessively.

Symptoms

The classic signs of a cat or dog with diabetes mellitus are PU/PD. These signs of excess drinking and urinating are subtle at the beginning stages of the disease and are easily missed. This is especially true in outdoor cats who do most of their urinating outside, and dogs that urinate outside also.

Other symptoms include weakness, an increase in appetite, occasionally a decrease in appetite, weight loss, lethargy, and rarely, vision problems due to cataracts (this problem is more common in dogs). Cats with a severe liver problem associated with this disease might have icterus (jaundice).

An affected cat might even walk abnormally on the rear legs (called plantigrade posture) due to nerve problems as a consequence of the elevated blood glucose level. It is also known as diabetic neuropathy, and tends to occur as the disease progresses. The best way to prevent it is to keep the blood glucose level as close to normal as possible.

This is what the abnormal (plantigrade) posture looks like

These are also the symptoms of other diseases commonly seen in dogs and cats, and can only be differentiated by diagnostic tests. These other diseases include, but are not limited to, hyperthyroidismkidney diseasecancerliver diseaseCushing’s disease and adverse reaction to medications.

The yellow discoloration to these gums is icterus (jaundice). It is commonly, but not always, caused by liver disease.

Symptoms in dogs typically include:

  • PU/PD
  • lethargy
  • poor appetite
  • vomiting
  • weight loss
  • diarrhea
  • cataract formation

Just like in cats, many dogs with diabetes mellitus were overweight at some time in the recent past.

Dogs with diabetes commonly have other diseases concurrently. They include:

Diagnosis

By the time a diagnosis of diabetes mellitus is made the disease process has usually been present for a significant period of time. When the disease process first started there were no obvious symptoms because of compensatory mechanisms in the body. As diabetes progresses these compensatory mechanisms lose their ability to maintain euglycemia. Eventually, symptoms of PU/PD and weight loss occur and your pet is brought in to be examined. This emphasizes the point that middle aged and older pets should have a routine blood panel and urinalysis every year once they reach 8.

This is a complex disease, and no specific set of symptoms tells us your pet has diabetes mellitus. It is important to follow the tenets of the diagnostic process closely when making a diagnosis of diabetes mellitus, especially since kidney disease and hyperthyroidism have similar symptoms. We will use the diagnostic process as an example of how we make this diagnosis:

Signalment

Typically this disease is seen in obese cats that are middle aged or older, and more commonly in males (the opposite of dogs). Orange cats seem to get DM more often than other colors, but that could be because more of them are male. There is no specific breed predilection in cats.

Dogs are typically middle aged and older, with purebred dogs showing a higher incidence. Common breeds are:

History

The classic signs of PU/PD, polyphagia, and weight loss occur in many cases, but not all. These signs depend on how well entrenched the disease process is before your pet is brought in for an examination. Sometimes the only thing an owner notices are accidents around the house in a previously housebroken cat.

A consistent finding is obesity in the recent past. This predisposes them to DM, and we sometimes call them pre-diabetic if obese enough. These obese cats need to be closely monitored for DM with fasting blood glucose tests, urinalysis, and fructosamine tests. You will learn about these tests in or diagnosis section.

Since this disease occurs in middle aged and older pets there can be other diseases occurring simultaneously. Some cats have a history of vomiting in the recent past, an indication that they might have had an episode of IBD (Inflammatory Bowel Disease) or pancreatitis. Some cats are borderline diabetics that have had a recent illness, stress, or adverse reaction to medication. There might also be blood in the urine or straining to urinate, an indication of a urinary tract infection.

Cats presented in DKA might have a history of abdominal pain and distention, vomiting, inappetance, and lethargy.

Physical Examination

The findings of the physical exam depend on how severe the diabetes is, how long it has been present, what caused it, and if there are any other disease processes occurring simultaneously.

Many cats will have lost weight, yet they still could be obese. There might be dehydration, weakness, lethargy, an enlarged liver on abdominal palpation, and an acetone (juicy fruit) smell to the breath. Hypothermia and shock could be present in advanced cases and those with DKA.

Diagnostic Tests

The primary method of diagnosis is with a fasting blood panel and a urinalysis. The blood panel will reveal hyperglycemia (at least > 200 mg/dl) while the urine sample will reveal glycosuria. Not every case of hyperglycemia means a cat has diabetes mellitus. Cats that recently ate, or those that eat canned foods that are rich in sugar, might have blood glucose levels higher than the normal range. Cats that are stressed from a car ride, on cortisone, are in heat, on phenobarbital medication or hormone medications, might also have hyperglycemia.

Cats are unique in that their stress response can cause a tremendous rise (up to 4x normal) in the blood glucose. This is a common occurrence when we take a blood sample in a cat, and needs to be taken into consideration when we analyze a blood report. This stress induced response is a normal reaction to the release of epinephrine (adrenaline). It is a transitory response and will not persist like the hyperglycemia of diabetes mellitus. These cats sometimes need to adjust to a hospital environment before we are able to determine their true blood glucose level. It is always advised to check the blood sugar in dogs and cats after an 8-12 hour fast to give an accurate representation of the blood glucose level.

Here is a blood glucose report from our lab for a cat that does not have diabetes mellitus. The blood glucose is 317.

This cat has diabetes mellitus, its blood glucose is 390

How do we differentiate them when both are well above the normal range?

Diabetes mellitus is diagnosed when there is a persistent fasting hyperglycemia along with glycosuria, that is consistent with a history of PU/PD and polyphagia.

Other blood tests are sometimes used in this disease. The two more common ones are serum fructosamine and glycosylated hemoglobin. They are used to to distinguish stress induced hyperglycemia from diabetes mellitus, and to also monitor insulin therapy. They give us an indication of what the blood glucose level has been for the preceding weeks.

Fructosamine is formed when glucose reacts with amino acids that make up serum proteins like albumin, which is made by the liver. When the blood glucose is high, fructosamine also increases. Increased levels of fructosamine help confirm a diagnosis of diabetes mellitus, give us an idea of the presence of a persistent hyperglycemia, and help us monitor response to treatment.

Glycated hemoglobin (HbA1c), a tool to diagnose, monitor, and treat diabetes mellitus in people, is just start to get clinical application to dogs and cats with DM. This hemoglobin A1c test gives us a greater timespan to monitor glucose levels, up to 70 days in cats and 110 days in dogs, as opposed to fructosamine which monitors glucose levels for several weeks.  The A1c test is is not affected by daily blood glucose fluctuations, exercise, diet, or the amount of insulin in the bloodstream. As this test is tested for consistency and become standardized and cost effective we will implement its use as another aid to monitor and treat or diabetic patients.

In addition to glucose in the urine and ketones, the urinalysis might indicate that a urinary tract infection is present. This is detected by a change in the pH of the urine, excess white or red blood cells, and bacteria. Even if these are not present a urinary tract infection can still be present. This is why we recommend a urine culture and sensitivity looking for bacteria.

This is a urinalysis from a cat that has diabetes mellitus. Its glucose is 4+. Fortunately, it is negative for ketones, there are no white or red blood cells present, and there are no bacteria visible either.

This cat does not have ketonuria or an infection.

Treatment

The goal of treatment is to resolve the symptoms of poor appetite, lethargy, and PU/PD without inducing hypoglycemia. Dogs tend to be easier to regulate than cats, although preventing cataracts from forming is difficult in the dog.

Some cases of diabetes mellitus in cats are not straightforward. An obese cat can have NIDDM in its normal, unstressed home environment. These cats are secreting insulin but in low levels. As long as they are in a stress-free environment they are able to maintain euglycemia. If they encounter a stressful situation, get sick, or are put on certain medications, their blood glucose will increase. If it goes beyond the renal threshold for glucose, PU/PD will ensue.

These cats are then brought to a veterinarian because of the PU/PD and diagnosed as having diabetes mellitus. They are put on insulin therapy and the problem improves. The problem occurs when these cats are returned to their normal environment and the problem that started the increased blood glucose in the first place (stress, illness, drugs) is now gone. In some of these cases these cats will now become hypoglycemic because they are being given insulin injections when they do not need them. Identifying these cats that have converted from insulin-requiring to non-insuin requiring NIDDM is difficult. This is one of the numerous reasons why diabetic cats should be brought to our hospital every 1- 3 months for a urinalysis and blood glucose curve.

If we start a cat on insulin injections, it’s weight is or becomes normal, and it responds well to insulin injections (especially glargine), we might have a cat in remission, which is our ultimate goal.  In these cases we start lowering the insulin dose slowly, over several weeks to see if it still maintains a normal blood glucose.

Hypoglycemia, blood sugar that is too low, is your primary emergency problem. Symptoms to watch for include:

  • Walking abnormally, like your pet is drunk
  • Running into walls or circling
  • Staring into space
  • Shaking

All diabetic animals, especially cats, need to be closely monitored because urine and blood glucose levels are in a constant state of flux. Because of this you need to be in touch with your pet’s habits and observant of any changes. You also need to have Karo syrup available at all times for dogs and cats in case their blood sugar becomes low and they have problems. If you have no Karo syrup make up some sugar water and rub it on the gums.

Diet

Recent evidence suggests that feeding a high protein diet will help cats with diabetes mellitus.  This higher protein diet mimics what a cat’s physiology has been used to for millenniums. It leads to less release of hormones that affect blood glucose levels. Some cats on high protein diets will need little if any insulin injections. Some cats that are on insulin injections to control their diabetes can actually go off insulin when put on a higher protein diet. The food we recommend is Hill’s M/D.

Dietary therapy might be all that is needed for the obese cat with NIDDM. A cat that is underweight from diabetes mellitus should not be put on a high fiber diet. Since this disease is prevalent in older cats this change in diet might be met with resistance. In these cases mix the higher fiber food with its regular diet to get some advantage of the higher diet. Do not feed foods that contain excess sugar like semi-moist canned foods.

Dogs tend to do well with Hills W/D. The most important thing to remember is consistency. Your dog and cat should be fed the food they like to eat, in the same amount, at the same time every day.

Oral Hypoglycemics

The goal of oral hypoglycemic medication is to minimize glucose absorption by the intestines and to also minimize the conversion of glycogen to glucose by the liver. They also help increase insulin secretion from the pancreas. Oral hypoglycemics need to be used early in the disease before the beta cells are exhausted. Since so many pets are brought to us well past that stage, they do not work as well as in humans.

They are used in cats that are not underweight, have negligible ketones in the urine, no indication of pancreatitis or no history of being on medication that could cause hyperglycemia. In conjunction with diet, oral hypoglycemics can sometimes help us differentiate NIDDM form IDDM. Cats with NIDDM will have significantly lower blood glucose levels when checked several days after initiating this protocol.

Some cats will vomit and might even develop hepatitis from oral hypoglycemics. Giving the medication with food helps minimize vomiting.

The main one used is Glipizide. Due to variable response and potential side effects it is not used often.

Insulin

The thought of giving injections to your pet, especially a cat, can cause panic in some people. Keep in mind it is easier to give insulin injections with the tiny needle that is used, than it is to give a cat a pill. Once we show you how easy it is you will become an expert in no time. If you make it a positive endeavor, feeding around the same time, then a small treat, or a brushing or petting session just after the injection, it will be a positive experience for both of you.

There are many types  of insulin that have been traditionally used to treat IDDM in our hospital over the decades. Unfortunately, the manufacture, Eli Lilly, has discontinued the production of many of its insulin products.


Regular

FastActing- Peaks in 2-4 hours Lasts 5-8 hours


NPH

IntermediateActing- Peaks in 8-12 hours Lasts 18-26 hours


Ultralente

ProlongedActing- Peaks in 16-24 hours Lasts 24-36 hours


This chart gives you a relative idea of their peaks and duration of action. It is important to remember that every dog and cat will react differently and will not necessarily have this same graph.

Regular insulin is used initially to treat a cat or dog if it has DKA. Once the ketoacidotic state has been reduced we use the intermediate or prolonged lasting insulin. Your veterinarian will let you know which one might be most appropriate in your situation. Sometimes we need to try more than one type of insulin. What is just as important as the type of insulin used is the familiarity a doctor has with a specific protocol.

Most pets will need insulin given every 12 hours. This should coincide with a meal. You should decide ahead of time what insulin and feeding schedule works for you and your lifestyle because consistency is of utmost importance. The same thing goes for exercise since this affects insulin. Take your dog for the same type of walk at around the same time every day when possible to increase your chance of a good response to insulin injections.

For many years the insulin used to treat cats was derived from a beef-pork combination (90% beef and 10% pork) that was used in human diabetes mellitus. The pharmaceutical companies are now relying more on human recombinant (genetically engineered) insulin.

The goal of insulin therapy is to mimic naturally secreted insulin from the pancreas as closely as possible. This can be quite difficult in any species, let alone the cat. The dose of insulin and the type of insulin that is effective will vary from cat to cat and dog to dog. Once a proper dose is initially determined at some point in time in the future this dose will probably change.

Initially, insulin is dosed conservatively in order to see an individual dog and cat’s response and to minimize any chance of hypoglycemia. After your pet has been on this initial low dose we like to do a blood glucose curve to assess where we are, then make adjustments in dose accordingly.

There are many different types of insulin used. We will go over the ones most commonly used:

  • Glargine and Detemir- Ultra long acting

    Glargine, a human insulin has been successfully used in many cats. If used early in the course of the disease it is even possible to get a remission of the disease.  Those cats that do go into remission need to be monitored and kept at an ideal body weight or they might have a recurrence of diabetes mellitus.

    Glargine is more expensive than the other insulin’s used. This added expense might be worth it if your cats diabetes problem is actually cured of the problem. One of our doctors will discuss this with you and see if it is appropriate in your situation.

    Glargine has been show to be effective in some cats, although its long term efficacy has not been proven yet in a large number of cats. The same holds true for Detemir. More studies with a large number of diabetic cats over a long period of time are needed.

  • PZI (Protamine Zinc Insulin)- Long acting

    This is one of the more commonly used insulins in cats. It is usually given every 12 hours. We start with a dose of 1-3 units, and adjust as needed.

  • Vetsulin (Lente)- Intermediate acting

    This insulin is approved for use in dogs and cats, and is one of the more common ones used, especially in dogs. Its use in cats is increasing due to good results. It is made from purified porcine insulin which has the same amino acids as canine insulin. Because of this there should be more effective regulation of blood glucose with less risk of anti-insulin antibodies. It is an intermediate acting insulin, and in some dogs once daily dosing is adequate. Cats usually need to be given their injections twice each day.

  • NPH (Neutral Protamine Hadedorn)- Intermediate acting

    This has been the mainstay for treating diabetic dogs over many decades. It is still used, although we have been using Vetsulin much more frequently. It is not used in cats.

Ketoacidotic Diabetes Mellitus

Pets presented with DKA need immediate medical attention. They need regular insulin due to its ability to rapidly lower the blood glucose level. They also need fluids and electrolytes to correct dehydration, electrolyte imbalance, and acidosis (a change in the pH of the bloodstream). If this therapy is initiated too aggressively it might cause more harm than good. Our goal is to return your cat to a relatively stable state within the first 1-2 days after initiating this therapy.

Regulation

Diabetic pets need to be slowly  regulated (the correct dose of insulin needed). Many pets will take 4-8 weeks to find the proper level of insulin Most cats have well entrenched pathology that is not conducive to rapid change. The dose has to be given in small amounts initially to prevent hypoglycemia. It takes several days for a cat to respond to a change in dose. This initial regulation only gives us a starting point for your pet’s insulin dose since there will be numerous mitigating factors that will affect insulin levels when your cat returns home.

Initially we will use a low dose and have you administer the insulin at home at this dose for the next 7 days. After 7 days we will perform a glucose curve in our hospital over 10 hours.  The blood glucose curve will give us an idea of how it is reacting to the type and amount of insulin we are using. Every pet is different, so this trending is needed to understand specifically how your pet will react. This curve will give us an accurate picture of just how high and how low the blood glucose is. This will then allow us to further refine the dose of insulin. We will do this glucose curve every 7 days, refining the dose each time, until we have achieved are desired level.

Any other problem your pet has, especially UTI’s (urinary tract infections) needs to be corrected for insulin injections to lower the blood glucose properly.

Our goal is to get the blood sugar level down to somewhere between 100-250 mg/dl. Some pets are regulated fine even if the blood glucose peaks at greater than 250 mg/dl. It is much better to have a pet that has a slightly high blood glucose level than to try and refine the dose so closely that hypoglycemia is risked.

To monitor your pets blood glucose we take frequent samples. To prevent the constant irritation from obtaining this blood sample we put a catheter into one of your cat’s veins. This eliminates discomfort and also minimizes the stress response.

This cat has jugular catheter — to learn more about catheters click here

 

The first step in the process of running a blood glucose test in our hospital involves taking blood from your pet and putting it on a special strip.

This cat’s blood glucose reading is 63 mg/dl. It is hypoglycemic at this point.

The typical pet eventually needs anywhere from 2-10 units given from once to twice daily. Of course this dose depends on the weight of your pet, the type of insulin used, its diet, its exercise level, and its individual response.

Even though these blood glucose checks are critical, your input as to how well your pet is eating, acting, and how much it is drinking and urinating, are just as important. If your pet is doing well in all these parameters then the blood glucose is being regulated.

Insulin Injections

It is imperative that you administer the precise amount of insulin required since small changes can have dramatic effects. Be consistent and give the insulin the same time and at the same location every day. If your pet is on twice daily insulin injections give each morning and evening dose at the same time every day. Always feed your pet in the morning prior to giving the insulin. If it does not eat its food skip the morning dose of insulin. If it eats only half of its food, give it only half of its insulin dose. Giving a normal dose of insulin to a pet that is not eating greatly increases the risk of hypoglycemia. You must always err on the side of hyperglycemia instead of hypoglycemia.

Most cats eat small bites of their food throughout the day. This might or might not work in a diabetic cat because of the manner in which the insulin that is administered peaks. If it does not work, feed your cat twice each day, feeding part of its daily meal when you give the insulin in the morning. Make sure it has access to this same food when the insulin level is peaking later in the day.

A record should be kept of your pet’s food intake to note any changes. The same thing holds for its water consumption. Marking this on a calendar weekly will give you important trends and give you a good idea if you are on the proper dose of insulin.

The actual administration of insulin is very straightforward. As a matter of fact, it is easier to give insulin injections at home than it is to give SQ (subcutaneous) fluids to cats that have chronic renal failure, a common feline problem. This is because an insulin injection takes 1 second to give, whereas fluids take 5-10 minutes. The technique used to give insulin injections or SQ fluids is the same- click here to view an actual demonstration of the administration of SQ fluids. When you are finished learning the proper technique return here to finish.

You will never be forced into doing something that makes you feel uncomfortable. While your cat is in the hospital with us you can observe how we give the insulin injections. One of our nurses will demonstrate its proper administration when we release your pet from the hospital. You can return to our hospital for assistance in giving the insulin at any time.

In order to simplify the process we will give you an insulin syringe that has been designed to be used with the specific type of insulin your pet requires. You will be giving insulin in a measurement called “units”, and not in ml (milliliters) or cc (cubic centimeters) as is commonly used in most syringes.

 

The use of injections is very simple. If we are using U-40 insulin, then we use a U-40 syringe. If we prescribe 2 units of insulin, draw up the insulin to the 2 mark on the syringe and give the injection. That’s all there is- no calculations are needed on your part.

Some cats require such a low dose of insulin that we have to dilute it for proper administration. A special diluent is needed for this, and diluted insulin should not be used longer than 2 months. A special syringe is sometimes used for dilute insulin.

This is what a U-100 syringe looks like. The needle is very small and sharp so your pet will not feel it during its injection.

Insulin should be kept refrigerated at all times to preserve its freshness. When you purchase it at the pharmacy bring an ice pack with you. Prior to use it should be gently warmed in your hands.  Storing the insulin bottle on its side in the refrigerator will help in mixing.

Gently roll it (never shake it vigorously because excess bubbles will form) between your hands for 1-2 minutes to bring it to the proper temperature for administration.

Make sure you are in a relatively calm location when you give the injection. Hold the insulin bottle upside down and draw out slightly more than the number of units your cat requires. Tap the syringe a few times to remove any air bubbles-this aids in accuracy (a few tiny bubbles are OK). Push the plunger in the syringe slightly forward until you have the exact number of units you need to administer is in the syringe. Put the cap back on the syringe and put the insulin bottle back in the refrigerator. Do not reuse the syringe.

We will show you exactly how to do this in person, and give the first few injections for you until you get your confidence. In this picture you can see we have drawn 6 units into the syringe.

Give the injection in the scruff of the neck just as you would when giving SQ fluids described above. Your pet should not feel anything because the needle is so tiny and sharp. The whole process, from warming the insulin to giving the injections, should only take a couple of minutes. As you get confidence it is recommended to rotate your injection sites. We can shave a section of hair to make this whole process easier.

Improper administration of insulin is one of the most common causes for improper regulation. Please do not hesitate to contact us at any time for assistance in this vital procedure. Unless unavailable, only one person per household should be delegated to giving insulin.

Home Monitoring

The best way to monitor your pets blood glucose at home is to perform the blood glucose yourself. Ears and pads are areas in which a small prick will give sufficient amount of blood to run an in home blood glucose. In some cats this method of obtaining a blood glucose level is preferable to running a glucose curve in the hospital. This is because the stress of the car ride and the obtaining of blood several times while in the hospital can mislead us as to your cats actual blood glucose level.

Some of our clients use a home glucose kit to check their cats. It is easy to do once we show you, and gives a more accurate assessment of blood glucose levels at home than does the glucose in the urine. You only need a few drops of blood for the glucometer.

To use the glucometer you need to find an ear vein. You can see this one running horizontally under our nurses finger.

It is very simple to prick the ear with this machine and get your sample

 After you place a drop of the blood in the green tip the machine will give you a blood glucose reading in a few seconds

Most people prefer to monitor the glucose in their pet’s urine because it is simpler. Monitoring of the glucose in your pets urine will give you at best a rough idea of its blood glucose level. There are significant limitations to home monitoring using urine glucose as a criteria. We do not recommend it.

Urine glucose measurements do not necessarily correlate with blood glucose measurements, the more important of the two. Also, if the blood glucose level is below the renal threshold a negative glucose in the urine cannot differentiate between euglycemia and hypoglycemia. If you note a significant amount of glycosuria consistently for several days your pet needs a blood glucose curve.

One of the ways the urine dipstick can be particularly helpful is in monitoring ketones. Occasional trace ketones is no cause for alarm. Consistent ketonuria in a cat that is not feeling well requires immediate veterinary care.

To help in the urine monitoring process your cat’s normal litter can be replaced with special litter that will not absorb urine. You can also use regular paper, newspaper, or even plastic wrap in the bottom of the cage. There is even a special litter that reacts with the glucose in the urine.

One of the more common urine dipstick kits is the Keto-Diastix. In addition to monitoring glucose it also monitors for ketones.

This is the chart on the Keto-Diastix bottle. The box to the far left is negative, which is the goal. The next box to the right is 100 mg/dl. Its OK to have this urine glucose value on occasion.

On the same bottle there is a chart to monitor for ketones in the urine. Your goal is to have negative with an occasional trace.

What is just as important as urine glucose is your subjective interpretation of how your pet is doing. If the original symptoms are greatly reduced then you are probably giving an accurate dose.

Determining the daily dose of insulin required at home is not an easy task. We have learned over the years that blood glucose determinations are variable, and that in many cases it is your perception at how well you pet is eating, how active it is, and how its drinking and urinating has decreased that is more important.

A more accurate blood test is the fructosamine level, which gives us an average of your pets blood glucose levels of the last 2-3 weeks, and is much less variable than individual blood glucose determinations. The fructosamine test is obtained at our hospital, and should be performed every 3 months after initial regulation.

Do not make any changes in insulin dose unless you talk with one of our doctors. Do not make daily changes in insulin doses either, wait 3 days to determine if the new dose is having any effect.

Warning signs that necessitate an exam and blood glucose curve in the hospital:

  • Lethargy or significant increase or decrease in appetite
  • Significant increase in drinking or urinating
  • (100 mg/dl) or more glycosuria for > 2 days
  • Significant ketones in urine for > 2 days

Long Term Care

It must be understood that in most cases insulin administration does not cure diabetes mellitus, it only controls it.  As you learned above in the physiology section, the body has very sophisticated and refined mechanisms to keep the blood glucose at optimum levels. This can not be replicated easily by giving insulin. The exception to this is the occasional cat diagnosed early in the disease process and is not overweight.  Glargine seems to be the best insulin to increase the chance of remission .

To minimize problems we should monitor your pets’s blood glucose level in the hospital and perform a urinalysis every 3 months. Since cats can exhibit an exaggerated stress response causing a profound hyperglycemia, a glucose curve is necessary to ensure accuracy. Every 6 months we should also perform a complete blood panel to look for changes in other organs caused by the diabetes. A urinalysis at the same time is needed to monitor for a UTI (urinary tract infection).

A further reason to run a complete blood panel every 6 months is to monitor routine age related changes like hyperthyroidism and kidney disease. Diabetes can also predispose your pet to high blood pressure (hypertension).

This long term monitoring is important for another reason. In almost every diabetic pet insulin requirements change, necessitating the need for close monitoring and communication with us. If your pet goes into heat (another reason to spay females and even neuter males) its insulin requirements might change. In some diabetic cats the problem goes away and they no longer have a need for insulin. Giving insulin to these cats can cause hypoglycemia, which if it is severe enough, can lead to seizures.

Complications of Diabetes

  • Hypoglycemia

    One of the more alarming, yet relatively rare side effects to insulin administration, is hypoglycemia. You should be ever vigilant about its appearance and always be ready to treat it at home. Close observation of your pets appetite will go a long way towards preventing this problem.

    Symptoms include shaking, a starry eyed appearance, lethargy, shaking, greatly enlarged pupils, muscle tremors and even seizures. If the problem is serious and persists long enough, coma and even death can occur from depression of the respiratory system. Some pets don’t show any obvious symptoms except subtle behavior changes like sleeping more than usual. Since cats sleep most of the time anyway this can easily be missed.

    In most cases the cause is an overdose of insulin. A common scenario involves a pet that eats significantly less than its normal amount for the day. Hypoglycemia can result if the dose of insulin is not adjusted to take this into account. If your pet is not eating well and you are unsure of its appetite, either give less insulin that day or do not give any at all. A blood glucose test in the hospital will let us know for sure.

    Other causes of hypoglycemia include improper insulin administration resulting in an accidental overdose, along with cats that spontaneously recover from their diabetes and no longer need insulin. This is why close monitoring of the blood sugar level is important, either at home or at our office.

    If the symptoms of hypoglycemia are mild, feed your pet some of its normal food. For many pets this will suffice. If the problem is severe use Karo syrup, a simple carbohydrate. It is readily available at the supermarket and should be kept on hand at all times. Give it in small amounts or rub it on the gums. Pancake syrup, honey, sugar water or any fluid that has high amounts of sugar can be used also. These high carbohydrate remedies only last a short time so you might have to keep on repeating one of them. Also, it is a good idea to have a source of simple carbohydrates in your car or other important locations when traveling or even just going for a walk. It pays to be prepared.

    In the rare case that your pet has a seizure or seems comatose from hypoglycemia, it is imperative that you do not put anything into its mouth, including your fingers.  These pets need to be seen by a veterinarian immediately.

  • Liver Disease

    Cats with diabetes are forced into using an energy source that will eventually cause a fatty infiltration of liver cells. As a result the liver will not function at optimum capacity, a potentially serious problem since the liver is such a vital organ. The liver enzyme test on the blood panel will alert us to this complication. When the diabetes is treated this problem might resolve. Radiography might reveal an enlarged liver (hepatomegaly) due to the fatty infiltration.

    This liver is larger than normal-it is extending towards the right far beyond the margin of the ribs. The 4 white arrows on the bottom outline the lower edge of the wedge shaped and enlarged liver.

    One of the most important disease syndromes associated with a fatty liver is called hepatic lipidosis. It occurs in overweight cats that are exposed to a stress that causes them to stop eating. This lack of appetite can become so severe that a feeding tube needs to be put in.

    Keeping the blood glucose level as close to euglycemia as possible will help minimize this complication. Again, the need for periodic blood glucose monitoring along with a routine blood panel every 3-6 months become obvious.

  • Somogyi Effect (Insulin Induced Hyperglycemia)

    Overdosing the morning dose of insulin can cause hypoglycemia. If the hypoglycemia becomes severe enough (< 60 mg/dl) the body will go through complex compensatory mechanisms to raise the blood glucose level. These mechanisms involve the liver, glucagon and epinephrine. If these mechanisms are unable to raise the blood glucose rapidly enough then the symptoms of hypoglycemia described above might occur.

    When these mechanisms are able to correct the hypoglycemia they can cause the blood glucose level to go quite high later in the day and persist through the night. If the urine glucose is measured just before the morning dose the next day there will be significant glycosuria due to the previous afternoon and evenings hyperglycemia. This will cause many people to increase the insulin amount in the morning dose. This overdosing will again cause hypoglycemia some time during the day, and the cycle will repeat itself.

    This problem is diagnosed by a blood glucose curve in the hospital. A cat with the Somogyi effect will have a blood glucose level that is abnormally low some time during the day. This emphasizes the need for a blood glucose curve to monitor your pet’s problem because only one blood glucose test during the day might miss the hypoglycemia episode that is causing this problem in the first place.

    Insulin antagonism

    Pets that are not regulated in spite of higher than normal insulin doses might have this problem. This problem can mimic improper storage, handling, and administration of insulin.

    There can be many causes to insulin antagonism. Hormones, cortisone, the Somogyi effect, adrenal gland disease, infection, chronic pancreatitis, kidney disease, cancer, anti-insulin antibodies, and even ineffective insulin all could be involved. Cats that get Feline Acromegaly, an excess of growth hormone, can also get insulin resistance.

  • Infections

    Diabetic pets are prone to infections, especially of the urinary tract. These infections makes them more prone to DKA and insulin antagonism. Good dental hygiene is critical also since many pets with diabetes have dental disease. Chronic dental disease can make regulation almost impossible.

  • Cataracts

    Almost all dogs with diabetes mellitus will eventually develop cataracts. The earlier the diagnosis is made the greater chance your dog’s blood glucose can be regulated to stave this off. One of our doctors might refer you to a veterinary ophthalmologist because there can be inflammation associated with this called uveitis. The cataract needs to be removed in this case to prevent pain and further complications. Your dog has to be properly regulated regarding insulin levels before the ophthalmologist can do this surgery.

Boarding a Pet with Diabetes

It is always preferable to keep your diabetic pet in its normal environment. When this is not feasible special precautions need to be taken if your pet is boarded. Cats that board away from home are at an increased risk of becoming unregulated as to their correct insulin amount. They will frequently have a diminished appetite, increasing their chance of hypoglycemia if their insulin dose is not adjusted. Your cat should be boarded only at a facility that is adept at treating this disease and can run a blood glucose curve in case of a problem. One of the more common reasons we board pets at our hospital is because they need this type of medical monitoring for their problem.

A fructosamine test should be performed just prior to boarding for us to get an accurate idea of your pets average blood glucose level.

You should bring your food and your insulin to the boarding facility. A feeding schedule with amounts of food and water consumed and at what times should be provided. Also include a timetable when insulin is given and at what amount.

Since diabetic pets should be monitored with a blood glucose curve periodically this is an ideal time to run this test. Many cats will adapt to their new environment in a short time, which should make their individual blood glucose tests more reliable. When your return to pick up your pet we will review this curve with you and adjust doses as needed.

Summary

It is obvious that this is a complex disease that requires diligence on your part for proper control. Since every pet is different, your doctor will make a custom plan that will work for you and your pet, and will not necessarily follow any pre-established protocol. Be prepared for constantly changing insulin requirements and potential complications. The more consistent you are with feeding the same food, in the same amount, at the same time(s) every day, will add to a successful outcome.

The majority of diabetic pets on insulin therapy have a significantly increased quality of life. This usually makes the time time and monetary commitment necessary for proper regulation well worth the effort.

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Disk Disease (IVD)

Breeders have selectively bred dogs over many years to obtain a certain look or to enhance specific qualities. One of the more significant tradeoffs with this breeding is the propensity for some breeds to have problems with their bone structure. In some dogs this affects the spinal cord.

At a minimum it causes discomfort, but unfortunately, it can cause more severe problems, including complete paralysis. When it occurs it is called intervertebral disk disease (IVD). It is one of the most common diseases causing paralysis of the rear legs in dogs.  It is estimated that up to 18% of dachshunds will have this problem. Even though it does occur in cats it is not a common disease in this species.

Neuroanatomy and physiology is a world unto itself, and is far too complex to cover completely in this page. It will be summarized and generalized for much easier understanding.

One of the most significant treatment modalities for IVD is called VNA, especially since no drugs are involved. We will talk about it more in the treatment section.

It is helpful to be aware of some of the medical terms involved with IVD:

analgesia- lack of feeling or pain hemi paresis or paralysis- problem with the front and back limb on the same side.
ataxia-incoordination para paresis or paralysis- problem with both pelvic limbs
paresis- partial paralysis mono paresis or paralysis- problem with just one limb
plegia- complete paralysis tetra paresis or paralysis- problem with all four limbs

Vertebral Anatomy

The dog has 31 vertebrae:

  • Cervical (neck)- 7
  • Thoracic (chest) – 13
  • Lumbar (lower back) – 7
  • Sacral (pelvis) – 3 (fused)

Let’s go on a tour of this anatomy by looking at overlapping radiographs:

The 7 cervical vertebrae are quite flexible, for obvious reasons. Disk disease can occur anywhere in the cervical vertebrae. C-1 and C-2 are called the atlas and the axis. There can be an instability in this area in large dogs that will cause neurologic problems. The term breeders use for this is “wobblers”.

As the cervical vertebrae become the thoracic vertebrae they go past the shoulder (S). The nerves that come off this cervical-thoracic junction at the shoulder are called the brachial plexus (you cannot see nerves on a plain radiograph). They innervate the front legs on each side. Each of the thoracic vertebrae corresponds to a rib (R) on each side of the chest.

As we continue down the thoracic vertebrae you can visualize how high their dorsal spinal processes are. Also notice how these processes start to get smaller as we get closer to the lumbar vertebrae. Thoracic vertebrae in this area do not typically cause disk disease.

Moving towards the end of the thoracic vertebrae we come to what is termed the thoracolumbar (T-L) junction. It is a very common area to have disk disease. As we pass into the lumbar vertebrae we have now made our way into the lower back.

The 7 lumbar vertebrae eventually lead into the sacral vertebrae. The fused sacral vertebrae are hard to visualize because they are within the pelvis. After the sacrum we are at the tail. The section between the last lumbar and first sacral vertebrae is called the lumbosacral (L-S) junction. Disk disease and arthritis here can be quite painful.

Spinal anatomy

The spinal cord is an extremely sensitive part of the nervous system. In essence, it is an extension of the brain. As the spinal cord moves from the brain down to the tail it sends out nerve branches (called nerve roots) that go to various organs. Some of these nerve branches bring sensation back to the brain. If you are painfully pinched on your skin it is the nerve branches in your skin that relay a feeling of pain from the skin, to a local nerve branch, and eventually along your spinal cord to your brain.

At the same time that these nerve impulses are going to the brain to tell you it hurts, there are other nerves in the spinal cord that go to the muscle near the area of pain and cause a reflex movement away from the pain. The nervous system is so sophisticated and sensitive that it actually stimulates your muscles to contract so you can move away from the painful stimulus without your brain having to tell the muscles to contract. Your brain perceives the pain, but by the time you feel the pain your muscles have already contracted.

These nerve branches that come off the spinal cord are very complex and overlap with other nerve branches. This makes localization of the exact nerve branch that is causing the problem a complex diagnostic problem. Added to the fact that our patients do not talk to us, the diagnostic challenge in figuring out exactly where on the spinal cord a dog is having a problem is no simple undertaking, and sometimes needs the aid of a specialist.

This side view of a spinal cord model shows 2 vertebrae (V) with a normal disk (D) in between. One of the nerve roots (NR) can be seen coming off of the spinal cord (SC). The head is towards the left, the tail towards the right.

To keep you oriented, this is the same area on a radiograph (at L1-2). The nerve root comes out of the dark structure that looks like a horse’s head. The disk, nerve root, and spinal cord do not show up normally on a radiograph. If the disk material becomes calcified it might show up.

This view of a spinal cord model is an end-on view of how the spinal cord fits into the spinal canal. You can see how the spinal cord is enclosed by bone. If it swells it has no place to expand into, resulting in serious damage to the cord.

Pathophysiology of IVD

Classification

  • Type I

    It occurs commonly in chondrodystrophic (poor cartilage and long bone development) breeds starting as early as 4 months of age.

    The disk loses its moisture content and starts to mineralize. The stresses of daily living, especially jumping up and down,  cause it to degenerate, ultimately rupturing its contents into the spinal canal and putting pressure on the nerve roots and spinal cord. The pressure can be so great that the blood supply to the spinal cord can be damaged also, leading to actual death of spinal cord tissue (myelomalacia). Once this starts there is no treatment, and these dogs will become paralyzed and die of respiratory failure.

    In IVD disease the disk material (red) in the space between the vertebral bodies puts pressure on the spinal cord and the nerve root that is leaving the spinal cord.

  • Type II

    This version of IVD occurs in larger dogs starting around 5 years of age. The changes in the disk occur much slower than in Type I disk disease. The disk bulges but does not actually rupture into the spinal canal. The spinal cord is not as severely injured and usually maintains its normal function. These dogs tend to show chronic pain and paresis.

The above classifications are helping in understanding IVD, but they do not always apply in every case. Large breed non-chondrodystrophic dogs can get Type I disk disease, and chondrodystrophic breeds can get Type II disk disease.

Degree of Damage

It is important to note that the speed at which a ruptured disk extrudes its material into the spinal cord is equally as important as how compressed the spinal cord becomes. Some dogs with minimal compression of the spinal cord can have severe neurologic problems because disk material extruded rapidly and severely damaged the spinal cord.

Cause

Trauma to a normal disk can cause disk material to extrude into the spinal canal. The most common cause is the natural degeneration of the disk that occurs in the chondrodystrophic breeds when young, and the larger breed dogs as they age. In most chondrodystrophic breeds it is the thoracolumbar area, the junction of the last few thoracic vertebrae and the first few lumbar vertebrae, that are involved.

Symptoms

The symptoms that occur vary from mild to severe. Much of it depends on which vertebrae is involved, how long the problem has been present, and whether the problem is Type I or Type II. It is important to follow the diagnostic process carefully when making a diagnosis.

The cervical (neck) vertebrae tend to have larger spinal canals for the spinal cord to pass through than do the vertebrae of the mid and lower back. When a disk puts pressure (whether Type I or Type I) the spinal canal has more room, so the spinal cord is subject to less compression in the neck than in the mid and lower back. Less compression means there is less of a chance that paresis or paraplegia will occur.

The following symptoms tend to occur with cervical disk disease:

  • Crying- especially when the neck is manipulated or when lowered to eat or drink
  • Poor appetite (anorexia)- pain can sometimes be so severe as to interfere with appetite
  • Muscle spasms and reluctance to move- another sequelae to the pain that can occur
  • One or both front legs might be lame- nerves to the front legs come out of the spinal canal at the cervical vertebrae.
  • Ataxia- pressure on the spinal canal at the cervical vertebrae can interfere with the nerves that innervate all 4 legs. Only rarely will this cause tetraplegia (paralysis).

When IVD occurs at the junction of the thoracic and lumbar (thoracolumbar) vertebrae, symptoms might be different than in the cervical version. Some of these symptoms depend on whether there is a Type I or Type II problem.

  • Crying in pain or shaking- a consistent symptom noticed by owners is their dog crying as if something hurts. It might happen spontaneously, or it might happen when you pet or pick your dog up. Those of us that have had a pinched nerve understand how severe this pain can become.
  • Reluctance to move- this might manifest itself as a hesitation to jump onto the bed, reluctance to go up or down stairs, or just laying around more than usual.
  • Poor appetite (anorexia)- the pain that occurs can decrease the appetite.
  • Ataxia to rear quarters- a dog might walk around as if the back end is going in a different direction than the front end. This is caused by pressure on the nerve roots that go to the rear legs.
  • Paraparesis or paralysis to rear legs- the pressure on the nerve root can become so severe that it can completely impair the nerve and cause paralysis.
  • Tense abdomen- this is called referred pain, and can mimic the symptoms of other diseases.
  • Hunched appearance- an additional problem related to pain
  • Fecal or urinary incontinence- these are relatively severe signs of thoracolumbar disease

This dachshund is exhibiting signs of pain to its rear quarters. His tail is between his legs and his abdomen is hunched up.

This dog is “down” in his rear quarters, a potential sign of IVD disease.

This dog is exhibiting serious signs of IVD. It is partially paralyzed in its rear legs.

When the problem progresses to this point these dogs commonly will not be able to urinate. The urine needs to be manually expressed before it passively overflows. Urine that stagnates in the bladder causes discomfort, stretches the muscles in the bladder wall so much so that muscle tone will not return, and sets up the stage for a bladder and kidney infection. This arrows outline the distended urinary bladder of a dog with this problem.

Diagnosis

Since the symptoms of IVD disease mimic those 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 that we do not overlook some of the diseases that are also encountered in pets as they age.

  1. Signalment

    IVD disease can occur at any age, although it tends to be a problem that affects middle aged and older dogs.

    Several canine breeds are prone to getting IVD. They are called chondrodystrophic due to the shape of their bones from breeding:

  2. History

    IVD disease is suspected in any pet that has some of the symptoms described above, especially if the dog seems in pain or has some degree of paralysis. Falling or being hit by a car gives us a clue that the spinal cord might be damaged.

  3. Physical Exam

    Routine physical exam findings might include:

    • Shaking
    • Increased heart and respiratory rates
    • Pain upon abdominal palpation
    • Pain when moving the neck
    • Weakness to the back end
    • Lameness to any of the legs

    During your dog’s exam you will notice one of our doctors checking some reflexes. This exam helps localize the problem and helps to verify that the problem is indeed IVD and not some other problem. Four of the more common neurologic tests will be explained:

    1. Panniculus

      This test is performed by poking the skin gently with a needle. If the pin is felt the muscles underneath will cause the skin to temporarily “crawl”. By finding the junction where the skin no longer crawls it is possible to help localize the nerve root (remember, they overlap). The affected nerve root is usually 1-2 vertebrae in front of the spot where the skin crawls.

    2. Proprioceptive deficits

      This is a postural reflex that tests the ability of a dog to recognize the placement of one of its limbs without actually seeing it. This tests the ability of the nerve to respond to the abnormal sensation to a foot that is bearing weight on the wrong surface.

      When the wrong surface is bearing this weight it sends a signal from the nerves in the top of the foot to the spinal cord segment innervated by that foot. When the signal gets to the spinal cord segment it also travels to the brain signaling that the foot is in an abnormal position. The brain then sends a signal back down the spinal cord to the muscles that innervate the foot telling them to contract and put the foot back into normal position.

      This is a sensitive test, and if a dog does not return its foot to a normal position immediately it potentially indicates a serious problem with the spinal cord.

      It is easily performed by placing the foot in an abnormal position. This dog should have returned its foot to a normal position immediately. Other diseases besides IVD can cause this problem (ex.- a fractured leg)

    3. Knee jerk (myostatic)reflex

      This is a spinal reflex that tests the ability of the spinal cord to react to stretching of the patellar tendon. If absent or diminished it indicates a potential problem with the nerve root. If exaggerated it indicates a potential problem with the spinal cord. Other tendons besides the knee can be checked for this reflex.

      Every pet has a different response to this stimulus, so it is usually repeated for accuracy.

    4. Deep pain (withdrawal) reflex

      In this reflex a toe is pinched, which normally will result in withdrawal of the limb away from this painful stimulus. This occurs independent of whether or not the pain is perceived at the brain level (you already learned this at the beginning of this page in the spinal cord anatomy section). A pet with a problem in its spinal cord will have the reflex, but will not realize it is painful because the nerves that travel along the spinal cord to the brain are injured.

      Dogs that show no reaction when a painful stimulus is applied to their legs are considered to have severe spinal cord injury. These dogs carry a poor prognosis for recovery, and most need immediate surgery.  This is a subjective test though, and needs to be performed numerous times for proper interpretation. Some dogs don’t consciously show signs of pain, so this critical test can be misinterpreted.

  4. Diagnostic Tests

    Radiography

    In some cases a radiograph is the diagnostic test of choice. Radiographs help determine if a dog’s pain or paralysis is due to IVD or some other cause. Other causes can include trauma, tumors, cysts, or infections of the vertebrae.

    Dogs that have IVD might have calcified disks, collapsed disks, even calcified disk material in the spinal canal. Dogs that are radiographed for IVD disease must be under sedated or under general anesthesia for proper technique and positioning.

    This dog has spondylosis, which is a form of arthritis due to instability of the vertebrae. This is not necessarily IVD disease. Some dogs with this arthritis are in pain and need medication, while others have no symptoms at all. Cats can get spondylosis also, although it is more common in dogs.

    This radiograph of a Pug shows a collapsed disk along with spondylosis between L- 2 and L- 3. You can tell it is collapsed when you compare it to the width of the disk in front and behind.

    This dog has IVD disease. There is calcified disk material in the spinal canal between L-2 and L-3, and it is painful and weak in its rear legs.

    This radiograph is from an 11 year old dog that is weak on one of its rear legs. The arrow points to the involved vertebrae. Foreign bodies and infections are possible causes, but most likely it is a tumor. What the owner that was a “tweaked back” on their pet turned out to be a tumor, emphasizing the importance of radiography in diagnosis.

    This is the same dog but from the VD view.

    Myelogram

    As good as an x-ray is in making this diagnosis, it does not give all the information needed in some cases. Plain x-rays do not allow visualization of the actual spinal cord or nerve roots. The dye injected during a myelogram outlines the spinal cord and allows much better visualization of any pathology in the cord. Injecting a radiopaque dye into the spinal canal is  of critical importance if surgery is contemplated.

    This myelogram is outlining the spinal cord in the lumbar vertebrae of a dog. The vertical column of dye at the top is where the needle was inserted to inject the dye. Now we can actually visualize the spinal cord itself.

    Magnetic Resonance Imaging (MRI)

    This tool is available to veterinarians and is very valuable in making a diagnosis of spinal cord disease. If the myelogram is inconclusive the MRI can provide valuable information on the health of the spinal cord.

    Cats can get spinal lesions also. This is the radiograph of a 15 year old cat with a lesion in its spinal canal at the arrow. This cat is painful and not walking well on its rear quarters.

    This is the x-ray and MRI report on this same cat

Treatment

Treatment depends on the severity of the problem and whether the problem is Type I or Type II. Fortunately, in many cases, especially if caught early, conservative therapy can be beneficial. Pets that have recurring problems might eventually need surgery.

  • Cage Rest

    This is the most important treatment modality short of surgery. Cage rest means exactly what is says; there can be no running, jumping, or playing. A crib or playpen will not work because dogs will try to jump out. It sometimes has to be utilized for several weeks for an adequate outcome.

    Dogs that are cage rested need to be monitored carefully for progression of the problem. Serial neurologic exams are used to monitor their condition. They should be hospitalized for the first few days in order to monitor their progress.

  • Medication

    Anti-inflammatory and analgesic medications are used routinely in Type I disease. Medications are highly beneficial in reducing pain and minimizing inflammation at the delicate spinal cord. The mainstay when it comes to medication is cortisone.

    Muscle relaxants are also used to minimize the spasms that accompany this problem. It is imperative that any pet with IVD that is put on medication is under strict cage rest. Pets that feel better with medication might be inclined to resume their normal activity, greatly increasing the chance that their spinal cord will suffer more damage.

    Our goal is to give just enough pain medication to make the dog more comfortable, yet not so much that the dog resumes its normal activity. If a dog’s condition improves with cage rest it should be continued for up to 3 weeks. Exercise should be restricted for an additional 3 weeks. Unfortunately, recurrence is common.

    Dogs that are unable to urinate properly due to this disease might also be put on antibiotics to prevent urinary tract infections.

    Dogs with Type II are routinely placed on anti-inflammatory medication. There are many highly effective ones available to veterinarians that greatly enhance a dog’s quality of life. You can learn more about these medications, called NSAID’s (Non steroidal anti inflammatories) in the treatment section of our arthritis page.

  • Surgery

    Surgery is the treatment of choice for recurring problems, dogs that have not improved with conservative therapy, or those that have neurologic deficits. Dogs that are paralyzed (paraplegic) in the back legs need immediate surgery. During the surgery the goal is to relieve the pressure on the spinal cord. This is done by removing a piece of the vertebral body or cleaning out the disk material that is putting pressure on the cord.

    Surgery is also used to verify a diagnosis since the actual spinal cord can be visualized. In addition, even if the prognosis for recovery from paralysis is poor, surgery can minimize pain at the spinal cord if an owner is willing to deal with the long term paralysis.

    Post operative care is important in dogs undergoing back surgery. They might need hydrotherapy, manual expression of their bladders, controlled walking with assistance, and lots of TLC.

    This chart gives an idea of how these treatment modalities are used. These are not hard and fast rules, but more of a guideline.

    Medical Therapy Surgical Therapy
    First episode of pain only Several episodes of pain only
    First episode of paresis or mild ataxia Several episodes of paresis or mild ataxia
    Medical conditions that prevent surgery Condition that worsens with only medical therapy
    Paralyzed and no deep pain response for > 48 hours Mild paralysis with deep pain response present
    Symptoms of progressing myelomalacia Paralyzed and deep pain response present for less than 48 hours

    A paralyzed dog can lead a very high quality of life. These dog carts work quite well.

  • Acupuncture

    A relatively new treatment modality for IVD in dogs is acupuncture. It can be helpful in dogs that are not paralyzed or in those where anesthesia or surgery are contraindicated. It is important to remember that it does not always work, and the prolongation of other treatment modalities should not be undertaken due to the severe and potentially irreversible nature of this disease.

    Dr. P wanted to make sure the needle did not hurt an already painful dog, so he volunteered to be the “pain guinea pig”. He is happy to report that there was no problem (and he could now actually dunk a basketball!).

    Here are the needles in use in addison (the Pug whose x-rays you saw previously).

  • VNA

    In the last few years our doctors have been using this treatment method in almost every case of IVD when the pet is not paralyzed. It has changed the way we look at this disease, and give us a new tool to treat without the use of drugs. Our VNA page has more details.

Prevention

Since this seems to be a heritable disease it is theorized that screening of dachshunds at 2 years of age with radiographs, looking for disk calcification, can be an early indicator for IVD. Keeping these dogs out of the breeding pool might decrease the incidence of this disease. This is similar to taking radiographs for hip dysplasia at 2 years of age to screeen for this problem before breeding.

Prognosis

IVD is a serious and potentially crippling disease. If your dog exhibits any of the previously described symptoms it needs an immediate exam by one of our doctors. If the problem is caught early enough the outcome of this disease is usually satisfactory. If you own one of the breeds that is predisposed to this disease it is important to closely observe for the symptoms of IVD disease.

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Ear (aural) Hematoma

On occasion we are presented with a pet that has a swollen ear. The swelling is due to blood vessels that have ruptured inside the ear flap, between the inside and outside layer of cartilage. This causes the ear to fill up with bloody fluid and after a period of time the blood in the ear clots and there is a firm swelling. If left untreated the ear will be painful and will eventually scar down, similar in appearance to a cauliflower ear in a prized fighter that has spent a lifetime in the boxing ring.

Symptoms

The symptoms of an aural hematoma are obvious. Depending on the severity of the problem there will be swelling, which is sometimes extensive. Almost every pet will either be holding the head to one side or either shaking and pawing at the affected side.

This cat has a moderate sized hematoma.

Cause

 

Pets that paw at their ears or shake their heads vigorously, especially those with large ears, can cause a hematoma. This pawing and shaking can be due to irritants around the face and ears, or irritants in the external ear canals like infections or foreign bodies (foxtails). Food allergy is a common cause of inflamed ears, causing your pet to shake its head excessively and burst blood vessels.

 

Medical Treatment

 

In some cases we can alleviate the hematoma by removing the fluid and injecting cortisone into the ear.

This dog is having fluid drained from its ear.

Your pet will also go home with oral medication to be used for 10 days. This treatment is usually repeated in one week, although some cases are healed after the first week of therapy. Pets that don’t heal after the second treatment need surgical correction.

The initial cause of the hematoma, often times an ear infection or food allergy, will be treated simultaneously.

 

Surgical Treatment

 

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.

Surgery-Monitor

 

It is advantageous in most cases to use medical therapy first because there is no need for general anesthesia, there is minimal discomfort to your pet, and the cost is less than surgical correction. Surgical treatment is used in those situations in which the problem is not corrected with medical therapy.

Some hematomas are too large or involved to attempt medical treatment initially. Another reason we might perform surgical correction before attempting medical correction occurs when your pet is being anesthetized for another problem simultaneously, for example, dental disease.

The following section has pictures of an actual hematoma surgery, and includes pictures of blood and ear incisions. If you would like to pass this section up click here.

The first step in the surgical procedure is draining of the fluid in the ear. An incision is made with a scalpel blade and the bloody fluid is drained.


Since most hematomas have been present for many days prior to presentation, there are blood clots in the ear. These clots are removed with a hemostat.


When all of the blood and clots are removed the ear is ready for suturing. You can readily visualize the 2 layers of cartilage in this view.


The 2 layers of cartilage are sutured together to prevent the bloody swelling from returning. The incision is left partially open to facilitate further drainage of fluid. We also bandage the ear to the top of the head in some cases. The bandage and sutures are removed in 7-10 days. Healing progresses rapidly and the ear returns to normal in no time.

 

For well over the 15 years this  surgery is done in our hospital with the laser. Using the laser has substantial advantages over the method described above. It is highly recommended that this surgery is done with the laser, particularly because it will dramatically minimize pain during the healing process.


Once your pet has a hematoma it is possible for it to recur. You should check your pets ears daily for any recurrence, treat the initiating cause, and clean them frequently.

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Ear Infection

A common problem in dogs and cats is ear infections. A consistent cause of recurring ear infections is an underlying allergy called atopy. Another name for atopy is allergic dermatitis. Food allergies are also a cause of this recurring ear infection. Some pets have both as the cause.

There are many different causes and numerous treatment regimens to effect a cure. Since the causes tend to be multifactorial we need to address all of them for a successful outcome. Dogs tend to have more of a problem with ear infections as compared to cats.

Hygiene is of major importance both in curing the problem and prevention of recurrence. Ear infections can easily become chronic in nature, so proper therapy early in the course of the disease is important, along with long term commitment to keeping the ears clean.

Long term problems with the external ear can progress to problems with middle (otitis media) and inner (otitis interna) ears. This can cause substantial pain, equilibrium problems, and even hearing loss.

Anatomy

Dogs and cats ears differ from human ears in several significant ways. The main difference is the shape and length of the ear canal. It is longer in animals and has a downward and then inward direction. Alaso, their ears are more sensitive than ours. Cleaning them requires more effort than in people.

This picture shows normal dog and cat ear canal anatomy. The arrows show the downward and inward path of the external ear canal. The tip of the arrow to the left is pointing to the ear drum. When you clean the ears you will gently be pulling up on the external ear to straighten this canal out and allow deeper penetration of medication.

A normal dog ear has glands lining it they contain cilia to remove normal debris. This self cleaning mechanism works well for a healthy ear, not so well for an inflamed and infected ear. Cleaning this debris out of the ear canal is imperative for the bodies normal cleaning mechanism to work.

Symptoms

Pets commonly give their owners a clue that their ears are bothering them. Most pets will either have discharge, odor, or will be shaking their head. Sometimes the ear flap will become extremely swollen-this is called an aural hematoma. Pets that have a foreign body in their ear like a fox tail will be shaking their head extensively and frequently paw at the effected ear.

Causes

Ear disease is caused by many different and predisposing factors, some of them working in combination:

  • Anatomy – deep ear canals and long floppy ears are predisposing causes because they set up a warm and moist environment that bacteria and fungi thrive in.
  • Breed – Some breeds like Cocker Spaniels are commonly effected because of allergies, long floppy ears, and inbreeding.
  • Allergy – In addition to causing itchy skin and hair loss in general, allergies can also cause ear problems. Food allergy and atopy are common causes.
  • Low Thyroid – On occasion low thyroid hormone can cause ear problems.
  • Parasites – Ear mites are also a cause of ear disease, especially in cats. Also chiggers and sometimes ticks.
  • Drug reactions – Any drug can cause a reaction that inflames the ear, including some cleaning agents.
  • Hygiene – Debris and excess hair in the ear canal can cause an infection.
  • Auto immune system diseases
  • Tumors
  • Sugar Diabetes
  • Cushing’s Disease
  • Feline Leukemia (FeLV) and Feline Immunodeficiency (FIV) viruses.
  • Canine Distemper
  • Bacteria – Staph, Strep, Proteus, E. coli, and especially Pseudomonas.
  • Excessive cleaning
  • Yeast – Candida and Malazzezia.
  • Foreign bodies – debris, hair, foxtails (plant awns).Since there are many causes to ear disease an accurate diagnosis is essential to relieving the problem. Several diagnostic tests are routinely used:

Diagnosis

A routine physical exam is used on every pet that is presented with ear problems because ear infections can be a sign that there are problems elsewhere in the body. This exam is an essential part of the Diagnostic Process, and might include routine blood work.

Ear swabs are used to obtain a sample of discharge for microscopic analysis

Microscopic analysis of the discharge helps us determine if your pet’s problem is bacterial or fungal related. This analysis is performed in our office by taking some of the discharge from the ear canal, staining it blue with a special stain, and observing how many bacteria or fungi are noted.

A culture of the discharge from the ear is sometimes used as an aid to determine what bacteria or fungus is causing the problem. Since many organisms are usually grown in a culture, and some of them are normal inhabitants, this test is not always advantageous. This picture shows a culture that grew out 3 different bacteria that are common to find in the ear canal. Organism #2 (Pseudomonas) is resistant (R) to all the antibiotics that are commonly tested.

The otoscope is an important tool that allows us to visualize the anatomy of the external ear canal, including the ear drum. It is also used to retrieve foreign bodies, usually foxtails, from the ear canal, and to check for tumors. Ear infections are painful, and some pets need to be sedated before they let us examine their ears.

 

Checking for proper thyroid level is an important test in every dog that has recurring problems, especially in Golden Retrievers. This is a report from a pet that has a low thyroid level.

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In addition to these tests, allergy tests are utilized when they are suspected as the cause of the problem. A blood sample is taken that tests for allergies to food, commonly found material inside of your house, and plant like materials found throughout our area in the outdoors. Your doctor will let you know if this test is needed.

Treatment

Each ear infection requires specific treatment depending on the results of the physical exam and diagnostic tests. If there are underlying problems your doctor will prescribe medication to prevent them. In the overwhelming majority of cases medical care is all that is needed. Surgical correction of an ear infection is usually used only after medical care has been unable to control the problem.

If your pet has recurring ear problems we need to control the allergy that is likely causing this. If it is atopy, there are many things we can do to either prevent exposure to the allergen causing the problem. Food allergy is a common cause of recurring ear infection, so a trial of Hill’s Z/D or D/D will be indicated. Our Allergic Dermatitis page has all the details.

For the majority of ear infections proper cleaning and routine topical medication will correct the problem. Learning how to clean your pet’s ears is crucial. Once you have an ear infection under control, which takes 3-7 days in most cases, your goal should be to clean your pet’s ears once or twice each week in order to prevent recurrence. Infections that continually recur are very painful and substantially decrease your pet’s quality of life.

In many mild cases we are able to clean the ears in our office without sedation. After we perform the initial cleaning in our office your job at home will be much easier. You will need to clean them at home to effect a cure and prevent recurrence. You do not clean them if our doctor is using Osurnia. Our nurses will demonstrate exactly how to do this with your pet. To learn the technique click here.

For pet’s with ears that painful to clean we will anesthetize them and thoroughly, yet gently, flush the debris out and instill medication. This is a huge start in your hygiene protocol at home.

Your doctor will routinely prescribe two medications. The first is used to gently clean the ear canal and remove debris and infection. The second medication is a combination preparation that kills either bacteria, fungi, or parasites. These medications usually contain an anti-inflammatory preparation to soothe the ear also. Occasionally your doctor will prescribe oral medication to clear up the infection and to decrease the inflammation in the ear canal.

We have many medications available to us that are very convenient at treating ear infections for dogs where daily cleaning and medicating is a problem. One of them is called Osurnia.

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Once we clean the ears we place this medication in the ear using the premeasured single-dose tube.  It contains three ingredients that are beneficial to clear up the infection, both bacterial and fungal,  and also sooth the ear. That is all you have to do for one week. In one week we recheck the ear to make sure the infection is getting under control, then we place another tube of medication in the ear. If your pet has no underlying problems as described above the infection is usually cleared up, and you don’t need to clean and medicate the ears daily. The ears are not cleaned again until 45 days have passed.

Many dogs have hair inside of the ear canal. If your dog is not having any ear problems this hair is left alone. If this hair is causing a problem it is removed to facilitate cleaning and to let air circulate into the ear canal. This should be done routinely, which for most dogs is at least once monthly. These ears are typical of a pet that needs the hair removed from its ears and a thorough cleaning. Sometimes just removing the hair from the ear canals completely corrects any problem, so please keep them hair free at all times.

These are the same ears after one of our nurses has cleaned them. It is obvious from the picture that this pet will feel much better from this treatment. It is a common sense approach and does not require any medication.

In some pets the ears are so inflamed that its painful to clean the ears. In these severe cases we use sedation and flushing. A warm cleansing solution is used to remove debris and infection from deep within the ear canal by flushing action only. These ears are painful and we need to go gently so as not to cause more pain and damage to an already severely inflamed ear canal.

This ear has had recurring infections for so long that it is no longer possible to clean the external ear canal. The canal is swollen shut, infected and very painful. The only adequate remedy in this case is surgical correction to completely remove the ear canal. It is extensive surgery and requires a surgeon with specialized training and expertise. The goal of long term ear care is to never let the disease progress to this point.

Here is another dog with the same problem as it is prepped just prior to surgery

 

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