Hypercalciuria and Urolithiasis in Rabbits
Kidney stones form in the urinary tract due to the deposition of complex compounds containing calcium in the urine. In rabbits, all the calcium that is consumed is absorbed, and urine usually contains 45-60 percent calcium (other mammals’ urine contains only two percent calcium). Rabbits between three and five years of age are at higher risk.
Symptoms and Types
Symptoms will ultimately depend on the location, size, and amount of material in the bladder. Some of the more common symptoms associated with kidney stones include:
- Blood in urine (hematuria)
- Urine staining in the perineum
- Straining/pain during urination
- Thick, pasty, cloudy, or beige- to brown-colored urine
- Hunched posture, tremors, and difficulty walking (when neurologic or orthopedic disorders lead to urine retention)
- Loss of appetite
- Weight loss
- Tooth grinding
- Swollen urinary bladder (may be palpable)
- Swollen kidney (may be palpable)
Commercial rabbit foods, such as pellets, typically contain very high content of calcium, much higher than the daily dietary requirements. This combined with factors such as inadequate water intake, lack of exercise, obesity, and incomplete emptying of the bladder can cause precipitation of calcium in the urine, ultimately leading to the formation of stones.
You will need to give a thorough history of your rabbit's health and onset of symptoms. Your veterinarian will then perform a thorough physical exam on your rabbit. The first step will be to differentiate between stones and other causes of abnormal urine output. Blood and urine analyses will be conducted to check blood and urine calcium levels, and an analysis will be done of any stone (uroliths) that are removed form the bladder. X-ray and ultrasound imaging can be used to reveal the presence, size, and location of the stones.
The first priority will be to relieve your rabbit from any pain it is experiencing. Treatment for the underlying cause of the stones will be next priority. Your veterinarian will try to manually massage the bladder to remove retained urine. If there is a blockage in the urinary tract, your veterinarian can use a flushing technique to push the stones out of the tract.
In some cases, surgery is required for removal of stones that are lodged in the urinary tract, or that are too large to pass through the tract safely. A short period of hospitalization for the surgery and stabilization are generally all that is required, with fluid supplements for rehydration. If urine staining and burn has occurred on the skin surrounding the genitals – i.e., the perineum and inside of the legs – zinc and menthol powder may be applied to keep the area dry and cool.
Living and Management
Your rabbit will require a warm, quiet environment to recover in. If the rabbit is not too tired, encourage exercise (hopping) for at least 10-15 minutes every 6-8 hours. This will promote a speedy recovery.
It is important that your rabbit continue to eat during and after treatment. Encourage oral fluid intake by offering fresh water, wetting leafy vegetables, or flavoring water with vegetable juice, and offer a large selection of fresh, moistened greens such as cilantro, romaine lettuce, parsley, carrot tops, dandelion greens, spinach, collard greens, and good-quality grass hay. Feed timothy and grass hay instead of alfalfa hay, but also continue to offer your rabbit its usual pelleted diet, as the initial goal is to get the rabbit to eat and to maintain its weight and nutritional status. If your rabbit refuses these foods, you will need to syringe feed a gruel mixture until it can eat again on its own. Unless your veterinarian has specifically advised it, do not feed your rabbit high-carbohydrate, high-fat nutritional supplements.
In some cases, the intestinal tract may have been affected as well, and surgery may be required to remove solids from the intestine. Possible complications include renal failure, urinary tract obstruction, or paralysis of the digestive muscles (due to anesthesia in surgery). After you have returned home, monitor your rabbit's appetite and production of feces, and report any abnormalities to your veterinarian immediately, as death may occur due to sudden and severe complications. Recurrence is likely, so it is important to decrease risk factors such as obesity, a sedentary life, and a poor diet. A combination of a lowered calcium diet, increased exercise, and increased water consumption for the remainder of the rabbit's life are all highly advised for the long term health of the rabbit.