Pet Care

Bladder Stones

Fluffy cat with pink bell around neck

What Are Bladder Stones?

Bladder stones are rock-like deposits of minerals, crystals and organic material that are found in a cat’s bladder. They can remain small in size or grow to be several millimeters in diameter, and may rub against the bladder walls, causing inflammation. Bladder stones can also lead to blockage of the urethra and can interfere with a cat’s ability to urinate. There are several types of minerals that form stones under different conditions in a cat’s urinary tract. The two most common are struvite and calcium oxalate stones.

How Can I Tell if My Cat Has Bladder Stones?

Common signs that may indicate bladder stones are:

  • Blood in the urine (hematuria)
  • Painful urination
  • Straining to urinate
  • Frequent urination
  • Genital licking
  • Chronic urinary tract infections
  • Urinary tract obstruction (especially in males)
  • Urine spraying
  • Passing urine in unusual places

Please note, sometimes cats with bladder stones exhibit no clinical signs.

What Causes Cats to Have Bladder Stones?

Different conditions contribute to the formation of different types of stones.  Some of these may include:

  • Nutritionally imbalanced diet
  • Decreased water intake
  • Urinary tract infection
  • High concentration of magnesium, ammonium and phosphate minerals in the urine
  • Urine pH favorable to the formation of various crystals
  • Certain drugs and dietary supplements
  • Congenital liver shunt
  • Breed predisposition

At What Age Do Cats Develop Bladder Stones?

Cats can develop bladder stones at any age. Some types of stones are more likely to form at different lifestages. The risk of developing calcium oxalate stones, for example, increases as your cat ages.

Which Cats Have a Greater Risk of Getting Bladder Stones?

It is believed that neutered male Burmese, Persian and Himalayan cats may be genetically predisposed to developing calcium oxalate stones.

How Are Bladder Stones in Cats Diagnosed?

If the stones are big enough, your vet may be able to feel them through your cat’s abdominal wall. However, radiographs, ultrasound, urinalysis and urine culture are most often used to diagnose bladder stones and determine the underlying cause.

How Can Bladder Stones Be Treated?

Your veterinarian will want to figure out what kinds of stones have formed in your cat’s bladder in order to determine the proper treatment. Surgical removal, which is also a form of treatment, is sometimes necessary in order for a laboratory analysis to be performed. Your vet may decide on one or more of the following treatments:

  • Vet-prescribed diet (to dissolve stones and modify pH)
  • Increased water consumption
  • Flushing procedure (filling bladder and inducing urination)
  • Surgical removal of stones
  • Sometimes cats—more likely females, whose urinary tracts are not as narrow as the male’s—will naturally pass the smaller stones when urinating.
  • Lithotripsy (breakdown of stones with shock waves)

How Can I Prevent Bladder Stones from Forming Again?

Once your cat has been diagnosed and treated for bladder stones, you’ll know what kind of stones he suffered from. Always have fresh water available for him and ask your vet if you should continue feeding your cat a special diet. Exercise is also important for keeping your cat’s system healthy. Your vet may recommend a urinalysis and urine culture several times throughout the year to test for crystals and/or infection.

What Can Happen if Bladder Stones Go Untreated?

Stones that go untreated may lodge in the urethra, causing a blockage—especially in males, who have narrower urethras—that may prevent your cat from urinating. Some signs of a urinary blockage are vomiting, nausea, appetite loss and a hard, distended abdomen. This is an emergency situation and will become fatal if not treated immediately.

Can Bladder Stones Indicate Other Health Issues?

Bladder stones can develop as a result of certain metabolic disorders. Diabetes mellitus and hyperthyroidism can lead to urinary tract infections, which can contribute to the formation of bladder stones.