Bladder Stones in Cats

Bladder stones, also called uroliths or cystic calculi, are minerals made up of tiny crystals that settle out from the urine and form little stones that can be as big as the bladder itself, or as small as a grain of sand. Bladder stones can form anywhere in the cat’s urinary tract. Be aware, male cats are ten times more likely to become blocked than female cats.

Signs & Symptoms of Bladder Stones in Cats

Straining to urinate
Frequent urination with little production (dribbling)
Blood in urine
Painful urination

Causes of Bladder Stones in Cats

Bladder stones will start to form in the urine under the right conditions in a cat’s bladder. When the urine becomes over-concentrated with these stone-forming crystals, the environment in the bladder is optimum for stone formation. The most common causes for stone formation are bladder infections, dietary factors, and metabolic disorders. If stones are large enough, blockage can occur and this becomes an emergency situation for a cat. If a stone lodges somewhere in the urinary tract, urine is not able to pass out and begins to back-up, causing a great deal of pain to your cat. This needs to be treated immediately.

Diagnosis of Bladder Stones in Cats

Diagnosis begins with a complete history and a physical exam of the cat. Your veterinarian will most likely do the following:

Upon exam, the bladder is palpated (examined by touch) and large stones can sometimes be felt in the bladder.
Radiographs - This will reveal large and medium stones. In some cases, contrast dye is injected into the bladder or given to your cat down the throat. It is then radiographed in order to see the stones on x-ray film.
Ultrasound - This can be used in many diagnostic processes to determine abnormalities in your cat’s body. Ultrasounds use sound waves that bounce back, producing an echo that measures the opacity of objects, and produces a picture on an ultrasound machine. An ultrasound of the cat’s bladder will reveal stones of all sizes.
Urinalysis - This test involves the collection of a urine sample. If your cat is blocked or will not urinate over time, your veterinarian may have to obtain the sample via cystocentesis, or by putting a needle through the abdomen into the bladder. The urine will then be examined visually, chemically, and microscopically for abnormalities. In the case of bladder stones, a urinalysis will reveal the presence of blood, crystals, and possibly casts in the urine. All of these are indicative stone formation.

Treatment for Bladder Stones in Cats

When large or multiple stones are found in the cat, the most effective treatment is surgery. The bladder is opened, the stones are removed, and the bladder is cleaned and flushed. This may sound a bit invasive, but if stones are too big to pass, they must be removed as soon as possible. If only small or passable stones are found, this can be treated with medication and monitored at home.

Prevention of Bladder Stones in Cats

Bladder stones can be prevented with special prescription diets. Once a stone has been present and it is analyzed for type, a special or prescription diet can be used to help alter the pH of the bladder and prevent the stones from forming. If your cat has a history of bladder stones, it is recommended that a routine urinalysis be done to maintain a handle on any bacterial infections brewing, so they can be treated in a timely manner. Also, always be mindful of any difficulty urinating you notice by your cat.

For determining a bladder stone problem in your cat, remove its litter from the box and when your cat urinates you can see if and how much, if any, blood is present.