Bladder stones / sludge (calculi)

Description

The presence of calcium in a rabbit's diet is important as too little of it can lead to teeth and bone formation problems.  On the flipside, too much of it can lead to a build up of calcium in the urinary tract and kidneys which may then form into bladder stones (or calcium stones).  Alternatively, it may not form stones but be present as a chalky substance clogging up the kidneys and bladder, known as bladder sludge.

Rabbit urine is normally slightly cloudy and this is caused by calcium present in the urine.  There is nothing inherent in a rabbit's physiology which regulates its calcium intake; therefore, a rabbit may often take in excess calcium and excrete it through its urine.    Diet alone is not the cause of bladder stones / sludge - some rabbits seem to be predisposed to it while in others it may be triggered by any of the following factors:

- rabbit not drinking enough
- rabbit not exercising enough
- dirty living conditions
- kidney or bladder disease
- diet high in calcium

Bladder stones or sludge may be diagnosed by physical examination, urine analysis or  X-rays.

Symptoms

- rabbit urinating more frequently / in unusual places
- rabbit straining to urinate
- blood in urine
- urine overly chalky, white and sludgy, may be sludge around tail area
- lethargy, depression
- loss of appetite
- a bladder stone may, on rare occasions, be passed by the rabbit and found in litter tray

Prevention / Treatment

Treatment of bladder stones may involve surgery if the stone cannot be passed and is obstructing the urethra.  For smaller stones and sludge, treatment may include hydration (by drip or by encouraging the rabbit to drink), flushing of the bladder, pain relievers and antibiotics.

Treatment and, more importantly, prevention may also include dietary changes.  Alfalfa hay, if fed, should be removed from the diet and the rabbit should be switched from mix to pelleted food, if applicable.  Too little calcium can be as harmful as too much, so dark leafy greens which are a natural source of calcium should still be fed.