Bladder Stones in Cats

Medically Reviewed by Amy Flowers, DVM on December 11, 2022
4 min read

Bladder stones, also known as “urocystoliths,” are stony collections of minerals, crystals, and organic material that collect in the bladder. People can get them, but so can your cat. They happen as a result of some kind of inflammation or disease. These rocks can remain small in cats, or they might grow to be several millimeters in diameter or larger. Stones can rub against the walls of the bladder, causing inflammation and pain. 

Bladder stones can also block the urethra and make it difficult or even impossible for your cat to urinate. Depending on the minerals that make up the stone, its shape and size will vary. The two most common types of bladder stone are struvite and calcium oxalate stones.

It’s not always easy to tell when your cat is injured or ill. Cats often hide when they are uncomfortable because it can be dangerous to show weakness in the wild. Cats are solitary creatures, so showing pain won’t bring help from others if they’re on their own. You will need to pay attention to tell if your cat has bladder stones. 

Common signs that may indicate bladder stones are:

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

No two cats are completely alike. Since there are several different types of bladder stones that can form, the cause of bladder stones in cats can vary. Some of these causes may include:

  • Poor diet
  • Dehydration 
  • Urinary tract infection or inflammation
  • Excess phosphate, ammonium, or magnesium in the urine
  • Urine pH out of balance
  • Dietary supplements or drugs that affect the urine
  • Congenital liver shunt
  • Breed predisposition

Do cats get bladder stones at certain ages? Cats can develop bladder stones at any age. Some types of stones are more likely to form at different life stages. The risk of developing calcium oxalate stones, for example, increases as your cat ages. These commonly show up in cats between 5 and 14 years old.

Do some cats have a higher risk of getting bladder stones? Common belief has suggested that neutered male Burmese, Persian, Siamese, and Himalayan cats may be genetically predisposed to developing calcium oxalate stones, but more research is needed to prove this for sure. Overweight cats, male cats, and older cats are more likely to develop these stones as well.

There are two methods of diagnosing bladder stones in cats. First, if the stone is big enough, your vet may be able to feel it by pressing on your cat’s abdomen. Most smaller stones must be diagnosed through ultrasounds or radiographs. These methods also help determine the cause of the stones. Your vet may start by performing a urinalysis, which can point to the likelihood of stones or help determine the likely type of stone.

Your cat’s treatment will depend on the type of stone that has formed. Once the stone has been examined, your vet may prescribe one or more treatments, including:

  • Special diet to dissolve and prevent stones
  • Better hydration
  • Bladder flushing
  • Lithotripsy, or the destruction of stones via shock waves

Your veterinarian may recommend surgical removal of the stone, both to treat any blockage and to identify what the stone is made of. Occasionally, veterinarians may also recommend that you simply wait and see if your cat passes the stone naturally. Female cats can often pass smaller bladder stones on their own. 

Sometimes, bladder stones can be the sign of a bigger health concern your cat already has. And if bladder stones go untreated, they can cause other problems, too. It’s important to get treatment to understand what caused them and to make sure they don’t cause any more trouble.

Untreated bladder stones. Untreated bladder stones can lead to a number of problems. If bladder stones block the urethra, your cat may be entirely unable to urinate. This can lead to symptoms including vomiting, nausea, loss of appetite, and a firm, distended stomach. In this case, urine can back up into the kidneys. A complete urinary blockage is an emergency and can be fatal to your cat, so get medical assistance immediately. 

Underlying health concerns. Yes, bladder stones are linked to other health problems. They can develop because of hyperthyroidism or diabetes, both of which may cause urinary tract infections and inflammation.

After the diagnosis, you’ll have a better idea of what’s been causing your cat’s bladder stones. With that knowledge, you can work to prevent them from returning. Provide constant access to fresh water, and consult your veterinarian about modifying your cat’s diet permanently.

Your veterinarian may recommend regular urinalysis to check for new stones, as often as every three months. They’re also likely to recommend regular frequent radiographs or X-rays every 6 to 12 months. You may also consider encouraging your cat to exercise to prevent the formation of further stones.