Urinary Tract / Kidney Stones (Cystine) in Cats

By PetMD Editorial on Feb. 5, 2009

Urolithiasis (Cystine) in Cats

Urolithiasis is described as the presence of stones or crystals in the urinary tract. When these stones are made of cystine -- a normal compound found in the body -- they are referred to as cystine stones. These stones can also be found in the kidneys and in the tubes connecting the kidneys to the animal's bladder (ureters).

Urolithiasis is primarily found in adult cats, and the Siamese and Domestic Shorthair breeds show the highest likelihood for cystine stone formation. Fortunately, the stones can be dissolved and removed without surgery in most cases, giving the animal a positive prognosis.

The condition described in this medical article can affect both dogs and cats. If you would like to learn more about how this disease affects dogs, please visit this page in the PetMD pet health library.

Symptoms and Types

Typical symptoms can include pollakiuria, dysuria, and an abnormal flow of urine (post-renal uremia).

Causes

The exact cause for urolithiasis is not currently known. In some cats, however, the inability to process proteins or amino acids has led to the development of cystine stones.

Diagnosis

Ultrasounds and X-rays are often performed to determine the size, shape, and location of the stones, helping the veterinarian come up with an appropriate treatment regimen. A urine test can also detect the presence of stones.

In some cases, a scope with a camera on the end (urethrascope) is used to examine the inside of the urinary tract for any abnormalities.

Treatment

The veterinarian will usually recommend using treatment options such as a special diet and medication [N-(2-mercaptopropionyl)glycine (2-MPG)] to reduce and eliminate the stones without surgery.

Living and Management

Follow all recommended dietary changes and administer prescribed medication. This will help prevent a recurrence of the stones. It is also important to bring the animal back to the veterinarian's office to ensure the stones have been successfully dissolved.