5 Types of Bladder Stones in Dogs

Many pet parents are shocked to see their dog’s X-rays reveal large stones in their dog’s bladder. Most commonly, dogs with bladder stones need to go outside every hour or have accidents in the house. Identifying this condition as early as possible is crucial since a urinary obstruction may be life-threatening and require immediate emergency treatment. 

The formation of bladder stones is caused by minerals in urine, clumping together to form a mineralized mass referred to by veterinarians as uroliths. It is common for dogs and cats to have these problems. 

How Do You Detect Bladder Stones in Dogs?

Initially, bladder stones are small but can grow in size and number over time. The following symptoms are typically seen in dogs with bladder stones:

• Frequent urination or urinary accidents.
• Frequent attempts to urinate without producing much urine.
• Having a difficult time urinating. 
• Urine that appears discolored.
• Licking at the opening of the urinary tract.
• Presence of blood in the urine.

It is important to confirm the diagnosis of bladder stones with an X-ray or ultrasound, as these symptoms can also be associated with other diseases affecting the urinary tract (infections and tumors, for example).

What are the Causes and Available Treatments for Bladder Stones in Dogs?

Minerals and other materials make up bladder stones. Struvite, calcium oxalate, urate, and cystine crystals make up most bladder stones in dogs. Urine samples viewed under a microscope can often reveal the type of crystal involved. A veterinarian may prescribe a therapeutic diet to dissolve the stones and crystals if struvite is diagnosed (e.g., dog antibiotics for urinary tract infections).

What are the Most Common Types of Bladder Stones in Dogs?

Struvite stones and calcium oxalate stones are the most common types of bladder stones in dogs. Other types of bladder stones include urate stones, xanthine stones, and cystine bladder stones. 

• Struvite Stones

A struvite stone is one of the most common types of bladder stones in dogs. Magnesium and phosphate stick together in urine to form struvite, a hard mineral deposit. The formation of struvite stones in dogs is usually caused by bacteria that produce ammonia in the urine.

Treatment for Struvite Stones in Dogs

Your veterinarian will likely recommend feeding a food formulated to dissolve struvite stones, in accordance with the American College of Veterinary Internal Medicine (ACVIM). Antibiotics are usually administered while dogs consume therapeutic dog food, and they may be administered longer if necessary. 

Your vet may also recommend surgery to remove the stones in the bladder or other procedures such as lithotripsy (breaking up the stones with ultrasonic shock waves). In most cases, surgical removal of the stones is the last course of treatment, unless there is a high risk of urinary obstruction that could put your dog's health at risk.

There is an increased risk of struvite stones in Shih Tzus, miniature schnauzers, Yorkshire terriers, Labrador retrievers, and dachshunds. Too much urinary acidification can lead to calcium oxalate stones.

• Oxalate Stones

A higher pH in dogs' urine can lead to struvite stones, but a lower pH can lead to calcium oxalate stones. When calcium and oxalate are supersaturated in urine, calcium oxalate stones form. Studies have shown that male dogs are more likely to suffer from calcium oxalate stones than female dogs, contrary to struvite stones. Dogs that are older are also more likely to suffer from this type of bladder stone. There was an average age of 9.3 years for dogs with calcium oxalate stones.

There is an increased risk of oxalate stones in Keeshonds, Norwich terriers, Norfolk terriers, and Pomeranians.

Treatment for Oxalate Stones in Dogs

In contrast to struvite stones, calcium oxalate stones cannot be dissolved with nutrients. They can instead be removed surgically or with non-surgical methods such as lithotripsy and voiding urohydropropulsion. 

• Urate Stones

Urate stones can be caused by a genetic condition, such as Dalmatians, Jack Russel Terriers, and Bulldogs, but can also be caused by liver disease, especially in cats or dogs with liver shunts. 

Treatment for Urate Stones in Dogs

Dogs with urate bladder stones have two primary treatment options: urohydropropulsion or surgical removal. Urohydropropulsion may be used to remove small stones non-surgically. A special urinary catheter technique is used to flush bladder stones from the bladder.

When bladder stones are too big to pass through urohydropropulsion, when there are a lot of stones in the bladder, or if there is a higher risk of urinary obstruction, surgical removal is often recommended.

• Xanthine Stones

A xanthine bladder stone is an uncommon urinary stone that occurs in both dogs and cats. Only 1% of stones in the urinary tract found in dogs are xanthine stones. When proteins are broken down, xanthine is produced. Xanthine is broken down into other substances by a specific enzyme (xanthine oxidase), which can then be eliminated from the body easily. The urine can contain elevated levels of xanthine if a dog lacks adequate levels of the xanthine oxidase enzyme. As a result, xanthine urinary tract stones form.

Treatment for Xanthine Stones in Dogs

Diet and medication are unable to dissolve xanthine urinary tract stones. Most of the time, bladder stones must be surgically removed. Depending on their location, stones can be removed via cystoscopy (an endoscope inserted in the urethra) or broken down using laser lithotripsy.

Increasing water intake is vital. A dog with a history of xanthine stones will require regular monitoring in order to prevent recurrences. It is important to check your dog's urine regularly to ensure it remains dilute and alkaline, and to detect xanthine crystals early.

• Cystine Stones

Cystine crystals are a relatively rare type of urolith in dogs. Dogs are more likely to develop bladder stones (uroliths or cystic calculi) than kidney stones. A genetic abnormality prevents dogs from reabsorbing cystine from their kidneys, which causes cystine bladder stones.

Treatment for Cystine Stones in Dogs

Just like other types of bladder stones in dogs, cystine stones can also be treated by urohydropropulsion or surgical removal. Small stones can be removed nonsurgically through urohydropropulsion while surgical removal is done when the stones are already too large or there is a risk of urinary obstruction.

Bladder stones originate in the urinary tract as a stony accumulation of minerals. If you feed your dog a balanced diet and provide him with lots of fresh water, you can reduce the possibility that he will develop bladder stones. Although annual veterinary check ups may not prevent bladder stones in your dog, they will help keep your dog healthy in general.