Urinary Stones and Sludge (hypercalciuria)

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Rabbits make wonderful pets, that need special attention from everyone in your family regarding their health 

Rabbits are prone to problems of the urinary tract.  These problems range from irritating sludge in the bladder, to kidney problems,  to the formation of a bladder stone that needs surgical removal. Sludge is urine thickened by calcium salts to the point of being chalky and thick in consistency, sometimes as thick as toothpaste. This causes problems in the urinary bladder usually, although it can occur in the kidneys or ureters. There are many factors why a rabbit might get this problem, so it is important to address all of them.

Rabbits need routine exams to ensure their health

Graphic photos on this page

Underlying Problem

As opposed to most other animals, rabbits absorb almost all the calcium in their food into their bloodstream. This causes a higher than normal blood calcium level relative to other animals. If an individual rabbit is not efficient at utilizing and eliminating any excess calcium through the urinary tract, a sludge or bladder stone problem might present itself.  Some of the factors we know about that might predispose a rabbit to a urinary problem with calcium include:

Genetics- Some rabbits are not as efficient at eliminating any excess calcium

Rabbits that are not good drinkers

Obesity

Sedentary lifestyle- rabbits that stay in a cage all day

A diet with excess calcium

Soiled litter pan area in a fastidious rabbit

Diseases elsewhere in the body can have an effect on a rabbit’s normal physiology, disrupting it to the point that they can stop eating and get dehydrated, leading to decreased kidney function and sludge or stones in the urinary bladder. You can learn more about them in our Rabbit Diseases section. The more common ones are:

GI Stasis

The dark round area in the center is a greatly distended stomach due to GI stasis

E. Cuniculi

The severe head tilt in this rabbit could be a sign of Encephalitozoon Cuniculi

Teeth Conditions

The point on this molar tooth could cause an inability to eat well over a period of time

Pasteurella

This conjunctivitis could be an indication of Pasteurella

Reproductive Disease

This is the radiograph of a rabbit with a uterus that is greatly distended. That large whitish area in the center of this abdomen is the uterus.

This is that fluid filled and greatly enlarged uterus during the surgery to remove this uterus

This male rabbit has a very large tumor in its left testicle. The surgeon is pointing to a normal sized testicle on the other side. The cancer was removed in a neuter surgery.

Urine that contains excess calcium will have the consistency of sludge. This irritates the bladder and urethra, causing significant inflammation and pain. If the problem persists long enough, a bladder stone (urolithiasis) might form.

In order to make a diagnosis of the problem in rabbits, we follow the tenets of the Diagnostic Process. This is a methodical and detailed way to approach diseases that ensures an accurate diagnosis. It includes:

Signalment- age, breed, and gender of an animal

History- what an owner has noticed at home about a pet’s specific behavior

Physical Exam- the findings from an exam by one of our veterinarians

Diagnostic Tests- What tests are used to make a diagnosis

Response to treatment- if the diagnosis is correct the pet should get better

Signalment

Urinary problems in rabbits can occur in all breeds of any age or gender. Young or old, large or small, male or female, it doesn’t matter.

History

Symptoms are variable, depending on the duration and degree of the problem, along with the individual rabbit’s tolerance for pain and discomfort. Some of the symptoms to watch for include the following:

Lethargy

Poor appetite

Diminished droppings

Urinating more than usual (pollakiuria)

Straining to urinate (stranguria)

Unable to urinate

Blood in urine

Chalky deposits on the fur in the perineal area

Moist or damp rear quarters from urine dribbling

Licking at rear quarters

Rubbing rear quarters

Skin rash in inside of rear legs or perineal area

Grinding teeth (a sign of pain)

Odor to urine

These are also the symptoms of other diseases in rabbits, so at the first sign of any of these problem you should bring your rabbit in for an exam with one of our veterinarians.

Physical Exam

Any sick rabbit gets a thorough physical exam by one of our veterinarians. It starts with body weight and temperature, and progresses to checking your rabbit from nose to tail for any physical abnormalities. Typical findings might include:

Low body temperature (hypothermia)

Underweight (low body condition score)

High heart rate (tachycardia)

Dehydration

Irritation to the perineal area

Neurologic deficits

Painful abdomen upon palpation

Small kidneys upon abdominal palpation

Distended bladder upon abdominal palpation

Bladder stone palpable upon abdominal palpation

Excess amounts of chalky or bloody urine when the bladder is expressed

Diagnostic Tests

Over the decades our body of knowledge regarding normal and abnormal values in diagnostic tests of rabbits has increased to the point that they are crucial for a proper diagnosis.

Blood panel

This test should be performed on all sick rabbits irregardless of the symptoms. It should also be performed yearly as part of the Wellness Exam on rabbits. These animals age rapidly, and oftentimes hide their symptoms, so it is important to have baseline normals on an individual rabbit, and to catch problems before they become entrenched and untreatable.

The blood panel in rabbits checks for a wide array of problems. It starts with a check of the red blood cells for anemia or infection. There are tests of the kidneys and liver, important organs to assess when we suspect a urinary or kidney problem in rabbits. We also check the electrolytes, and especially the calcium level.

This rabbit has blood abnormalities that can happen with a sludge problem, and also many other problems

Urinalysis

This will check for white blood cells, red blood cells, and crystals in the urine. We also assess the specific gravity and the protein and glucose levels, in addition to looking for signs of bacterial infection.

Urine Culture and Sensitivity

If we suspect a urinary tract infection (cystitis) we will take a sterile sample of urine directly from the bladder and attempt to grow out any pathogenic bacteria. If they do group out, we will check many different antibiotics to find out what antibiotic that particular bacteria is sensitive to and will kill it. This report takes 2-3 days.

This pet has a Staph. infection, that is sensitive to several different antiboitics

Radiography (X-rays)

It is important to radiograph any sick rabbit. There are a multitude of problems that can occur on the inside that are not apparent externally during our physical exam.

This is what a radiograph of a rabbit looks like. The important abdominal structures are labeled:

K- kidney

B- urinary bladder

Cecum- our appendix

Did you notice the spinal fracture? Without this radiograph, we would not have known this.

This rabbit is laying on its back for a radiograph. The arrow points to the left kidney because this rabbit has significant sludge in its bladder, and we wanted to assess the kidneys. Do you notice anything else?

The two lower arrows point to the different appearance of the wings of the ileum of the pelvis, which could indicate bone cancer. We would never had known this if we had not taken a radiograph. 

The sludge that occurs in the bladder, and the stones that also might occur, have a large amount of calcium carbonate in them. This means that they are radiopaque, and show up vividly on an abdominal radiograph.

The small whitish area in the center of this radiograph is some sludge in the urinary bladder of this rabbit. This small amount is of no significance in a rabbit with no symptoms of disease.

This rabbit has more sludge in its urinary bladder. This amount may or may not be of significance, depending on how this rabbit is doing, other diagnostic tests, and follow up radiographs.

S- stomach

K- kidneys

This rabbit is not eating well, is lethargic, and has an odor to its urine with urine scalding on the perineum. It needs to be treated for sludge in its bladder. Can you identify other organs besides the sludge in the urinary bladder? The radiograph below labels the organs. 

H- heart

L-liver

S-stomach

The cecum and sludge are obvious. In the radiograph above, did you notice the calcifications in the kidneys, circled in red?

Same rabbit as above, this time laying on its back. The large amount of sludge in the urinary bladder is even more apparent in this view.

You can see the calcification of the kidneys in this view also

This is what a distended bladder looks like at necropsy

In addition to sludge, rabbits with urinary problems can get bladder stones. Other names for bladder stones are urolithiasis and cystic calculi. These stones also occur in dogs and cats. They are handled differently in the rabbit though.

Click here to see how we take care of bladder stones in dogs and cats.

Click here to learn more about how we do surgery at the Long Beach Animal Hospital in a wide variety of animals.

These are bladder stones in the urinary bladder

Bladder stones in rabbits are removed surgically. We take special precautions in all rabbits when anesthetizing them. Our Anesthesia page has more details on anesthesia.

We have a team of people present when we anesthetize a rabbit

They are closely monitored while under anesthesia 

We approach rabbit surgery like any other surgery using aseptic surgical techniques.

Everyone in the surgical suite practices aseptic surgical techniques

We use the laser to make an incision into the bladder and remove the stone. Note the lack of bleeding on this highly vascular urinary bladder when using the laser. 

After any anesthetic procedure we closely monitor our patients until full recovery

Ultrasound

This is a precise and highly accurate way to assess the kidneys and urinary bladder, and it complements radiography. We also check the other organs in the abdomen carefully with ultrasound.

This is an ultrasound of the urinary bladder with a bladder stone

In this ultrasound the kidney it is being measured

Treatment

In the acute phase sludge is removed with gentle manual expression. If your pet has a chronic problem with sludge in the bladder we can teach you how to do this at home. Flushing the bladder, after manually expressing most of the sludge, helps complete the process. We might sedate your rabbit if we need to pass a urinary catheter to flush out of the sludge.

We might need to hospitalize to provide intravenous (IV) fluids in a dehydrated rabbit and to help support the internal organs like the kidneys. Pain medication is commonly used, along with assist feeding for those rabbits not eating.

If a bladder stone is present we will remove it surgically.

Once your rabbit is stabilized our goal is to help prevent recurrence of  the stone. This is done by you at home in many ways:

Adding water to the food if your rabbit is not a good drinker

Giving supplemental (SQ) fluids under the scruff of the skin to increase urine output

Showing you how to express the bladder

Show you how to assist feed

Keeping the litter box clean

Decrease the weight if obese by feeding less, and increase activity

Using medications as prescribed by us if one of our doctors think it is indicated. This could include:

Pain medication

Antibiotics

Cranberry juice

Vitamin C (ascorbic acid)

Using food that does not have an excess of calcium might be helpful. This means no pellets or alfalfa hay.

Feed only Timothy, Oat, or Orchard Grass hay. A small amount of fruits, and grass hay based pellets can be fed

Also feed fresh leafy green vegetables like kale, mustard greens, dandelion parsley, broccoli leaves and romaine lettuce.

If your water is hard (lots of minerals in it like calcium) you might want to get a water softener.

Follow Up

Any rabbit that has a sludge or bladder stone problem is susceptible to recurrence. Routine monitoring by physical exam, blood panels, and radiographs every 3-6 months is needed to catch the problem early.

Our Rabbit Diseases section has  more information on rabbits, including how we surgically repaired the fractured femur in the radiograph below. This is put here as a reminder that rabbits have powerful back legs in relation to their spine and long bones. If not restrained or held properly they can easily fracture these bones. A femur can be repaired, a fractured spine cannot.

This is called a mid shaft transverse fracture of the femur

Don’t forget to give your bunny lots of TLC, like Dr. Kennedy is doing here on one of her patients