What you need to know about Kidney or Bladder Stones (Urolithiasis) in Rabbits
Urolithiasis, also called kidney or bladder stones, is a condition that is often seen in rabbits. The disease most commonly affects the bladder, but can also occur in the urethra, ureter and kidney.
Development of the disease
Rabbits can be afflicted with stones (uroliths) due to the unique way they metabolize calcium. High dietary calcium levels caused by diets high in calcium-rich foods such as alfalfa pellets and alfalfa hay, or high calcium vegetables such as kale. collards, chicory or dandelion can contribute to a high calcium content in the blood, a condition called hypercalcemia. Any calcium in the body that exceeds the bodily requirements of the bunny are then excreted almost entirely by the kidney. This can, in turn, lead to high urinary calcium levels (called hypercalcuria). It’s these high urinary calcium levels that can cause bladder sludge or sand and potentially cause stone formation.
While signs of trouble may vary, a sudden loss of litterbox habits, straining to urinate, slow and painful spasmodic (a drop-by-drop) discharge of urine — possibly even with with blood , wetness around the genitals, or a “thick” or “pasty” urine signals problems. In advanced cases, the bunny may have obvious abdominal pain, a hunched posture and be grinding his or her teeth loudly (called bruxism). Other signs could include not eating, lethargy and weight loss. Any of these symptoms require a visit to the vet as soon as possible.
Once at your vet’s office, he or she will ask for a complete history, including information about bunny’s activity level and a review of the diet. It’s very important to give complete information, including what treats are given, so that the vet has a full picture of your bunny’s daily routine. This information will help to determine possible causes and, ultimately, help you to develop a plan of prevention once the bunny has recovered.
Once a complete history is taken, your vet will most likely do a urinalysis and he may draw blood for a blood chemistry. X-rays and/or an ultrasound of the abdominal area (the bladder, kidneys, urethra and ureter) to look for sand (or sludge) and stones may also help him to confirm a diagnosis.
In rabbits with sludge or sand in the bladder, the vet may flush the bladder with a high volume of fluids (or crystalloids) and may place the bunny on antibiotic therapy. If surgery (or cystotomy) is required to remove a stone (called a urolith), a culture and sensitivity test (sometimes called C&S) will be done and antibiotics prescribes. The stone will also be sent out for analysis.
Diet: In most cases, dietary modification to reduce calcium levels is required. This will usually involve switching the bunny from alfalfa-based pellets and/or hay to a Timothy hay-based pellet and grass hay such as Timothy, Oat, Orchard, etc. In addition, replacing high calcium vegetables with lower calcium ones will help decrease overall intake.
Exercise: Increasing exercise can help to prevent a build-up of sludge in the bladder by preventing the sand (calcium crystals) from settling to the bottom of the bladder and allowing it to be excreted with the urine.
Orlando Diaz-Figueroa, DVM, MS, Dipl. ABVP (Avian Specialty)