Urinary Stones Cats & Dogs

Uroliths are commonly referred to as “stones” and can occur in any section of the urinary tract. Bladder or urinary stones are common in both our canine and feline patients. Regardless of specific type, they occur when the urine becomes too concentrated with certain components (precursors like crystals or mucous) and the environmental conditions of the bladder are appropriate for their formulation. Two main types of bladder stones exist: struvite and calcium oxalate stones. These types of stones are normally visible on radiographs (X-rays). Although there are a few less common types that do not show up on X-rays. Often there are also crystals in the urine of a bladder with stones. But, the type of crystals does not always correlate with the type of urinary stone.

Struvite Stones

Struvite stones tend to form in urine that is alkaline (higher pH). Dog’s with struvite’s commonly have urinary tract infections (UTIs). In cats, the presence of struvite’s is not as closely associated with a urinary tract infection, though infection can still be present. Sometimes diet changes can alter the pH and dilute the urine to dissolve these stones. This can take a long period of time. As stones get smaller with diet modification, there is a risk they will become lodged in the urethra. The urethra is the tube that carries urine from the bladder to outside the body.If the urethra gets blocked this is an a life threatening urinary obstruction!!!! Because of this risk, many veterinarians recommended surgical removal of the stones. The removal is often done at the time of diagnosis with diet changes after surgery to prevent additional stones from forming.

If you suspect your pet has a urinary blockage or is having trouble urinating, contact your veterinarian immediately. This can be a life threatening condition and requires immediate attention. Any trouble going to the bathroom requires immediate action.

Calcium Oxalate

Calcium oxalate stones form in concentrated urine with more acidic urine (lower high pH). They are not normally dissolvable with diet and need surgical removal. It is important to follow up surgery with diet change to keep the urine dilute enough to prevent the reformation of calcium oxalate stones.

Other stones

There are a few other types of stones that are less common in our veterinary patients. Some animals have genetic predisposition for forming these less common stones. Underlying liver problems can also cause the formation of certain types of urinary stones. Your veterinarian may need to do more tests to diagnoses these other types of bladder stones.

Follow up care

After surgical removal or dietary dissolution of a stone. Follow up with your veterinarian is important to ensure you are doing everything you can to prevent their reformation. Frequent checks of urine pH and urine concentration are important to monitor the efficacy of diet on modification of the bladder environment. It is also important to keep the bladder free from infection to decrease risk of new stone formation (especially struvite’s). Vet’s do this by culturing (trying to grow bacteria) from a urine sample. Sterile urine samples are normally obtained through a sterile collection process (cystocentesis). Your veterinarian will guide you through the follow up plan best to keep your pet stone free. These plans often include a change of pet food.


Pets need to go the bathroom!! If your pet dog or cat is having trouble going to the bathroom, go to the vet now!!!

Who can get urinary Stones?

  • Urinary bladder stones are common in both our canine and feline patients.

Types of Urinary Stones

  • The two most common types of urinary stones we are: struvite and calcium oxalate stones. There are also less common types of stones that may occur.

Possible Diagnostics:

  • Radiographs.
  • Urinalysis and Urine Culture.
  • Ultrasound.

Possible Treatments:

  • Surgical removal.
  • Dietary dissolution: There are multiple diets designed to help this process.
  • Medical Treatments.

The information provided does not constitute veterinary advice. Please contact your veterinarian to discuss any possible questions you have about your pet’s health.

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