Bladder Stones in Cats

Bladder disease in the cat is a frequently recognized problem. It can occur in both male and females, but can be more serious of a problem in the male cat. Causes of bladder disease include simple bacterial infection, bladder stones and or crystals (minerals which merge to form bladder stones), infection within the bladder wall, and cancer or tumors in the bladder itself.

In the majority of cases, infection by itself, or accompanied by bladder crystals is seen. If crystals are present, they usually cause irritation and infection in the bladder before merging into forming bladder stones.

Common symptoms include straining to urinate, frequent attempts to urinate, spending a long time in the litter pan, producing small amounts of urine at a time, urinating outside of the litter pan, and blood in the urine.

Because male cats have a narrower urethra (tube leading from the bladder to outside the body) than female cats, bladder crystals in the male cat can often times obstruct the flow of urine by clogging or blocking the urethra . Blockage of urine flow is considered a medical emergency.

If allowed to continue, this blockage of urine flow backs up toxins in the cat's blood stream normally cleared by the urine. This accumulation of toxins can lead to a lack of appetite, vomiting, severe weakness, abnormalities with the heart rhythm, and ultimately death.

Treatment in the case of urine blockage, is aimed at restoring the flow of urine. A catheter inserted in the urethra acts to "break through" the blockade of crystals, thus allowing for evacuation of the urine. Most cats affected with crystals or stones usually have accompanying infection requiring antibiotics.

Not all cats develop crystals in the bladder. Affected cats may have a genetic cause behind the crystal development. These cats require special diets and or medications to eliminate their bladder crystals, and prevent them from recurring.

In some cases of urinary blockage in the male cat, surgery is required to allow them to urinate freely again. The surgery acts to widen the urethra, allowing for crystals to pass rather than to clog the urethra. Usually the cats requiring surgery, have not responded to the urinary catheter treatment, and continue to re-blocked after removal of the catheter. Surgery is aimed at reducing the chance of urine blockage but does not alter the development of bladder crystals. These cats will still require appropriate diets and medications to prevent crystal formation.


Female cats rarely block, unless stone formation has occurred. In which case, the stones are wide enough to clog the urethra, blocking the flow of urine. Surgical removal of the stones is usually required.

Persistent infection in which there are no crystals or stones, may have bacteria lodged within the bladder wall. This is called interstitial cystitis, and can be difficult to cure. Antibiotics often times are unable to penetrate the bladder wall to get at the bacteria. Medical and surgical procedures are performed to reduce the amount of tissue along the wall of the bladder that the bacteria have to "hide" in. This then allows the antibiotics a chance to affect the bacteria and cure the condition.

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