Kidney Stones in Cats and How to Help

Updated April 4, 2018
Cat getting checked by veterinarian

Cats with kidney stones are likely to be in a great deal of pain and may display a number of telltale signs. Even though these stones can be a serious medical condition, they can be treated with help from your veterinarian.

Understanding Kidney Stones

Kidney stones get their name from their "rock" shape, although their actual clinical name is nephrolithiasis. The stones can be formed from several substances such as struvite, urate and calcium oxalate. Most cats with kidney stones will have ones made of calcium oxalate. Inside of the kidneys exist nephrons, which work to filter a cat's blood to form urine. Kidney stones that become too large to pass through the nephrons cause a blockage which can become a serious condition that is both painful and could irreversibly harm a cat's kidneys.

It is actually common for cats to have kidney stones and never show any signs of discomfort. The stones only become a problem when they become blocked when trying to move through the kidneys. It's possible for cats to pass a stone on their own without veterinary intervention but even so, it is still quite painful and your veterinarian can prescribe pain medication to make your cat more comfortable.

Symptoms in Cats

If you see your cat displaying the following symptoms, it's time to take them to your veterinarian right away:

  • Your cat may experience difficulty or pain during urination. The cat may strain physically when squatting to pee or make distressed vocalizations.
  • Because urination is painful, you may see your cat urinating more often and in smaller amounts.
  • Blood may appear in their urine.
  • Your cat may stop using the litter box and urinate in other places in the house.
  • Obsessive grooming of the genital area that is part of their usual behavior pattern is another sign.
  • Your cat may lose their appetite, vomit or lose weight.
  • Their behavior may change from their normal routine, with more hiding, shyness and a depressed or lethargic appearance.

Causes of Kidney Stones

Just as in humans, kidney stones in cats can become a problem because of the daily diet. Cats that do not take in enough water each day can be at risk for kidney stones. Cats that are only fed a dry kibble diet are also at risk. Some commercial cat diets can lead to higher pH levels in a cat's urine, making it alkaline which, in turn, can increase the formation of stones.

Cats that frequently have urinary tract infections are more likely to develop kidney stones. If your cat also avoids the litter box, this may mean he or she is holding their urine longer, which can also lead to kidney stones.

There is also a genetic factor. Siamese, Persian, domestic shorthair and domestic longhair cats have a higher incidence compared to other breeds.

Diagnostic Techniques

Your veterinarian will be able to find kidney stones through X-rays or an ultrasound. He or she may also perform a urinalysis and blood work to check for infection and any changes in your cat's kidney function. You may be asked to provide a complete medical history so the veterinarian can learn about any past issues with urinary tract infections, your cat's daily diet and any other symptoms you have observed.

Treating Kidney Stones

The type of treatment will depend on the diagnostic tests, which may result in no treatment if the case is mild and the stones can pass through on their own. If your veterinarian does prescribe a treatment plan, it may include one or more of the following.


Medications, like antibiotics, can help break up the stones and treat infection. The veterinarian may also give your cat a prescription for Urocit-K once the stones have passed to help prevent more stones from forming in the future.


A specially formulated prescription diet food that is low in protein and will often include wet canned food can help increase your cat's fluid intake. Some popular prescription foods that you can obtain through your veterinary clinic or online are Hill's Prescription Diet K/D, Royal Canin Renal Support E, and Iams Veterinary Formula Renal Multi Stage. You will also be encouraged to provide a constant supply of fresh water for your cat.


In particularly severe blockages where your cat needs immediate help, your veterinarian may perform surgery to remove the stones. This is known as an ureterotomy. They may also treat the condition with an endoscopy. In most cases, non-surgical interventions are preferred as cats can pass the stones with the help of diet, medication and fluids.

A Treatable Condition

Kidney stones can range from a mild to deeply painful condition in cats. It is treatable and measures can be taken with your veterinarian to decrease your cat's discomfort and prevent enlarged stones from forming again in the future.

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Kidney Stones in Cats and How to Help