Bladder Stones in Cats
Written by Small Door's medical experts
Bladder stones, scientifically known as cystoliths or cystic calculi, are a common condition for felines. These stones range in size from microscopic to several millimeters (or even larger!) in diameter, and can have mild to life-threatening side effects in cats. Bladder stones in cats are formed when minerals and other substances clump together, or aggregate. This can lead to mild or serious complications, including irritation of the bladder lining, urinary tract infection, and urethral obstruction. All cat owners, especially owners of male cats, need to understand the signs and risks associated with bladder stones to help reduce the risk of a life-threatening obstruction.
In This Article
Symptoms of bladder stones in cats are typically associated with urination. If your cat has bladder stones, you may notice the following:
Frequent urination
Small, frequent amounts of urine
Bloody urine
Painful or difficult urination
Urinating outside the litter box
Straining to urinate without producing urine
Abdominal pain
General malaise
Bladder stones irritate the lining of the bladder and can increase the risk of bladder infections. You may notice that your cat takes frequent trips to the litter box, but produces only small amounts of urine. You may also notice that your cat shows signs of pain during urination, or that the urine appears bloody. Some cats even urinate outside the litter box.
Bladder stones can also lead to a urinary obstruction if the stones lodge in the urethra. This condition, which is significantly more common in male cats than in female cats, is deadly without veterinary intervention. The signs of a urinary obstruction include abdominal pain, vomiting, repeated trips to the litter box, yowling or crying while in the litter box, and straining to urinate without producing urine. If you notice your cat straining to urinate, contact your veterinarian or veterinary emergency clinic immediately.
Bladder stones in cats form as a result of minerals and other substances clumping together to form stones. Cats have acidic, highly concentrated urine. This predisposes them to developing stones, but there are other factors that can contribute to stone development.
Common causes include:
Urine pH levels
Diet
Inflammation or infection
Veterinarians are not entirely certain what starts the process of stone formation, although it is believed that excessive amounts of urolith-forming minerals in the urine clump together. What we do know, however, is that once the hardened center of the stone forms, it gradually increases in size as it adds layers. This process can take weeks or months. Diet, inflammation, and infection—factors that can cause changes in the mineral content and pH levels in your cat’s bladder—can all trigger stone development.
pH plays a large role in stone development, as well as the type of bladder stones that are formed. The two most common in cats are calcium oxalate and struvite. Calcium oxalate stones develop more commonly in acidic urine. Struvite stones, on the other hand, form more commonly in alkaline urine. While uncommon, urate stones are associated with vascular shunts or liver disease.
Veterinarians diagnose bladder stones in cats in several ways. Very large stones may be felt on palpation, but most stones require radiographs to diagnose. Calcium oxalate and struvite stones both show up in radiographic images; however, some stones may be too small to be seen. These stones can usually be detected by an abdominal ultrasound.
Routine blood and urine tests also help veterinarians diagnose bladder stones, as well as any resulting urinary tract infections. Urinalysis may reveal microscopic crystals (although it’s possible for cats to have stones without crystals, and crystals without stones).
The treatment for bladder stones in cats depends on the type of stone and the severity of the symptoms. In the case of struvite stones, a prescription diet may resolve the problem by dissolving the stones. Certain other types of stones may also be dissolved with medications and prescription diets.
Unfortunately, calcium oxalate stones cannot be dissolved with changes to diet or medication. These stones must be removed. In some cases, they can be fragmented with a laser during cystoscopy. The fragments are then flushed out. However, a type of bladder surgery called a cystotomy is more common.
Urinary obstructions are a veterinary emergency. Cats with blockages may require surgery, and most will also require fluids and hospitalization. Without treatment, death may occur in as little as two to three days as toxins build up in your cat’s body.
Bladder stones can also lead to urinary tract infections. This will require additional treatment and medications like antibiotics to resolve.
Is There a Cure for Bladder Stones?
Yes. Bladder stones can be cured by removing them from the bladder. In some cases, further stone development can be prevented through diet. However, some stone types cannot be managed this way, and cats may develop stones again in the future.
Are Bladder Stones Contagious for Humans or Other Pets?
Bladder stones are not contagious for humans or other pets.
What Is the Cost for Treating Bladder Stones?
The cost for treating bladder stones will depend on several factors. When considering costs, be sure to account for vet clinic visits, diagnostic imaging, blood work and urinalysis, exam and hospital fees, and the possibility of surgery. This can range from hundreds to thousands of dollars. In the case of an obstruction, emergency fees and hospitalization may also apply.
As always, keep in mind that costs vary based on geographic location—bigger cities have a higher cost of living, which also applies to veterinary care.
Bladder stones in cats are managed in several ways. Cats with struvite stones may require a prescription diet for the rest of their lives to decrease the risk of recurrence. It is very important that these cats are not fed any other foods or supplements, as this can counteract the diet.
Regardless of whether you manage your cat’s bladder stones with diet, medications, or surgery, your cat will require follow-up care. Repeat imaging and urine tests are often recommended 1, 3, and 6 months after initial diagnosis and treatment. Cats predisposed to stones may require additional long-term monitoring.
Most cats recover well from bladder stones. However, cats with obstructions may have a more guarded prognosis.
Bladder stones in cats can be prevented in some cases with canned food. This increases the moisture content in your cat’s diet, which may reduce the chances of stone development. Veterinarians typically do not put cats on prescription diets unless they have been diagnosed with bladder stones.
Is There a Vaccine for Bladder Stones?
No. But if your cat has already dealt with a case of bladder stones, talk to your veterinarian about ways you can reduce your cat’s risk of developing them again in the future.
Bladder stones are uncomfortable and potentially life-threatening. They cause frequent, painful urination, and often difficulty urinating, and can cause secondary issues such as UTIs and blockages. They require immediate veterinary treatment; depending on the type of stone, they may be treated with a prescription diet, laser treatment or surgery.
