Urinary Crystals and Bladder Stones in Cats


Urinary crystals and bladder stones are collections of minerals that form in the urinary tract. They can range in size from microscopically small to several millimeters in diameter. While crystals may not cause any symptoms, larger stones can cause irritation, inflammation, and even dangerous urinary blockages.

What causes bladder stones?

The most common cause of bladder stones is low water intake, often the result of feeding a dry diet. They can also be caused by a high concentration of minerals in the urine. Certain drugs and dietary supplements may contribute to the formation of crystals and stones. Cats with congenital liver shunts may be at increased risk of developing crystals and stones, as are some breeds, such as male Persian, Himalayan or Burmese cats.

Symptoms of urinary stones

Cats with urinary stones may show many of the same symptoms as cats with other urinary tract diseases, such as urinary tract infections or kidney disease. Symptoms may include frequent urination, straining to urinate, painful urination, urinating outside the litter box, and licking around the genitals.

How are urinary stones diagnosed?

Diagnosis will include bloodwork (blood chemistry and blood count), urinalysis and radiographs. Ultrasound may also be used to diagnose stones. Cats with bladder stones don’t always showsymptoms, and the stones are often discovered as part of a routine exam and lab work. If the stones are large enough, they can be felt on palpitation.

The two most common types of bladder stones are struvite stones and calcium oxalate stones.

Treatment of bladder stones

Treatment will depend on the type of stone that has been diagnosed. For struvite stones, dissolution with a special diet may be an option for some cats to avoid surgery. This is not always successful. It takes several weeks, not all cat will eat the special diet, the ingredients in the diet are not optimal, and cats will need to be monitored closely for the possibility of a urethral obstruction during the dissolution process.

The most common treatment for bladder stones is a cystotomy, in which the bladder is surgically opened and the stones are removed. Cats usually recover quickly from this common surgery.

Bladder stones can also be treated with laser or shockwave lithotripsy. These treatments are usually only available at specialty hospitals or veterinary schools. This treatment breaks the stones into smaller pieces that can then be passed through the urinary tract.

How to prevent bladder stones

Feeding a moist (canned or raw) diet and providing plenty of fresh water at all times is the best way to prevent bladder stones and other urinary tract disease. Urinary tract disease in cats has been linked to stress, so keeping the cat’s environment stress-free and minimizing changes in the cat’s routine can also help.

Bladder stones can be seen in cats of any age, but are more frequently seen in older cats. Being alert to any changes in your cat’s normal litter box routine can help detect problems early.

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