Bladder Stones in Cats: Types, Symptoms & Treatment

Types of Bladder Stones in Cats

The two most common types of bladder stones in cats are struvite stones and calcium oxalate stones. According to the American College of Veterinary Surgeons, while the development of these stones is complex, a cat's food may play a role. They also rarely form secondary to bladder infections in cats.

Radiographs and a microscopic exam of urine sediment may provide indications as to what type of stone your cat has. However, the identity of a stone cannot be determined unless it is collected and analyzed.

Calcium Oxalate Stones

Calcium oxalate stones are the most common urinary stone in cats, according to the Merck Veterinary Manual. They're most often seen in middle-aged to older cats. Breeds most likely to develop calcium oxalate stones include the Ragdoll, British shorthair, exotic shorthair, Himalayan, Persian and Scottish fold. Calcium oxalate stones can form in overly acidic urine. They may be seen in cats with elevated blood and urine calcium levels secondary to a condition called idiopathic hypercalcemia or in cats with chronic kidney disease.

This type of stone requires surgical removal. Infections and underlying conditions must also be treated. Once the stones have been removed, switching your cat to a therapeutic food formulated to reduce urine mineral content and increasing their water intake — by switching them to wet food, for example — may help prevent a recurrence. It's necessary to have your cat adhere to your veterinarian's recommended meal plan.

Struvite Stones

Struvite stones are typically found in younger cats who've been neutered. Unlike calcium oxalate stones, struvite stones in cats tend to form in highly concentrated alkaline urine. While any breed can be affected, those most at risk are the domestic shorthair, exotic shorthair, Ragdoll and Himalayan. Cats who consume high amounts of magnesium, phosphorus, calcium, chloride and fiber are also more likely to develop struvite stones.

A special therapeutic food, such as Hill's Prescription Diet, can help dissolve struvite stones. Therapeutic urinary foods come in a variety of flavors and forms and therapeutic treats may be available so your cat will not be deprived. In many cases struvite stones can be dissolved quickly. One study showed that stones were, on average, 50% smaller in just 2 weeks and the average time to completely dissolve stones in about a month. In most cases, it's recommended that a cat remain on a therapeutic food to prevent stones from returning. This is becase while a cat that may no longer be symptomatic of urinary issues, recurrence is possible if the cat resumes eating a food that contributed to stone formation in the first place. Keeping your cat on a pet food formulated for urinary health may help extend the time between urinary problems.

While bladder stones in cats have a high recurrence rate, they can be successfully treated. Together you and your veterinarian can determine the right therapy or combination of therapies to keep the stones at bay.