5 Types of Bladder Stones in Dogs

Many pet parents are shocked to see their dog's X-rays reveal stones in their bladder. Dogs with bladder stones most commonly need to go outside frequently or may have accidents in the house. Identifying this condition as early as possible is important, as a urinary obstruction may require prompt veterinary attention.

The formation of bladder stones is caused by minerals in urine clumping together to form a mineralized mass referred to by veterinarians as uroliths. This is a condition seen in both dogs and cats.

How Do You Detect Bladder Stones in Dogs?

Bladder stones start small but can grow in size and number over time. The following signs are typically seen in dogs with bladder stones:

• Frequent urination or urinary accidents
• Frequent attempts to urinate without producing much urine
• Difficulty urinating
• Urine that appears discolored
• Licking at the opening of the urinary tract
• Blood in the urine

It is important to confirm a diagnosis with an X-ray or ultrasound, as these signs can also be associated with other conditions affecting the urinary tract, such as urinary tract infections or tumors.

What Causes Bladder Stones in Dogs?

Bladder stones are made up of minerals and other materials. Struvite, calcium oxalate, urate, and cystine crystals make up most bladder stones in dogs. A urine sample viewed under a microscope can often reveal the type of crystal involved. A veterinarian may recommend a therapeutic diet if struvite is diagnosed, and may also prescribe antibiotics for associated urinary tract infections.

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

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

 

• Struvite Stones

Struvite 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. Struvite stones in dogs are usually associated with bacteria that produce ammonia in the urine.

Treatment for Struvite Stones

Your veterinarian will likely recommend a therapeutic diet formulated to help dissolve struvite stones, in accordance with guidance from the American College of Veterinary Internal Medicine (ACVIM). Antibiotics are often prescribed alongside the therapeutic diet and may continue longer if necessary.

Your veterinarian may also recommend surgical removal or other procedures such as lithotripsy, which uses ultrasonic shock waves to break up the stones. Surgical removal is typically considered when there is a risk of urinary obstruction.

Breeds with an increased risk of struvite stones include Shih Tzus, miniature schnauzers, Yorkshire terriers, Labrador retrievers, and dachshunds.

 

• Calcium Oxalate Stones

A higher urine pH can contribute to struvite stones, while a lower pH can contribute to calcium oxalate stones. These form when calcium and oxalate are present in high concentrations in the urine. Studies suggest male dogs are more commonly affected by calcium oxalate stones than female dogs. Dogs with calcium oxalate stones have an average age of around 9 years.

Breeds with an increased risk include Keeshonds, Norwich terriers, Norfolk terriers, and Pomeranians.

Treatment for Calcium Oxalate Stones

Unlike struvite stones, calcium oxalate stones cannot be dissolved through diet. They are typically removed surgically or through non-surgical methods such as lithotripsy or voiding urohydropropulsion.

 

• Urate Stones

Urate stones can be linked to a genetic predisposition in certain breeds such as Dalmatians, Jack Russell Terriers, and Bulldogs. They can also be associated with liver conditions, particularly in dogs or cats with liver shunts.

Treatment for Urate Stones

Dogs with urate bladder stones are typically treated with urohydropropulsion or surgical removal. Urohydropropulsion uses a specialized urinary catheter technique to flush smaller stones from the bladder non-surgically. Surgical removal is recommended when stones are too large to pass, when there are many stones present, or when there is a higher risk of urinary obstruction.

 

• Xanthine Stones

Xanthine bladder stones are uncommon, accounting for approximately 1% of urinary stones in dogs. When proteins are broken down, xanthine is produced. Normally, an enzyme called xanthine oxidase converts xanthine into substances that can be eliminated from the body. When a dog lacks adequate levels of this enzyme, xanthine can accumulate in the urine and form stones.

Treatment for Xanthine Stones

Xanthine stones cannot be dissolved with diet or medication and typically require surgical removal via cystoscopy or laser lithotripsy. Increasing water intake is important for dogs with a history of xanthine stones, and regular urine monitoring is recommended to detect crystals early and keep urine dilute and alkaline.

 

• Cystine Stones

Cystine stones are a relatively rare type of urolith in dogs. They are caused by a genetic condition that prevents the kidneys from properly reabsorbing cystine, leading to elevated levels in the urine and eventual stone formation.

Treatment for Cystine Stones

Like other bladder stone types, cystine stones can be treated with urohydropropulsion for smaller stones or surgical removal when stones are too large or when there is a risk of urinary obstruction.

 

Keeping Your Dog Healthy

Bladder stones form when minerals accumulate in the urinary tract over time. Feeding your dog a balanced diet and ensuring access to fresh water daily can help support overall urinary and general wellness. Regular veterinary checkups are an important part of keeping your dog healthy at every stage of life.

Frequently Asked Questions

What are bladder stones in dogs?
Bladder stones, also called uroliths, are mineralized masses that form in the urinary tract when minerals in urine clump together. They can vary in size and type and may cause signs such as frequent urination, difficulty urinating, or blood in the urine.

What are the most common types of bladder stones in dogs?
Struvite and calcium oxalate stones are the most common. Other types include urate, xanthine, and cystine stones, each with different causes and treatment approaches.

How are bladder stones diagnosed in dogs?
A veterinarian will typically confirm the diagnosis using an X-ray or ultrasound. A urine sample may also be examined under a microscope to identify the type of crystals involved.

Can bladder stones in dogs be treated without surgery?
In some cases, yes. Struvite stones may be dissolved with a therapeutic diet. Other types, such as calcium oxalate or cystine stones, cannot be dissolved and may require surgical removal or procedures like lithotripsy or urohydropropulsion.

Are certain dog breeds more prone to bladder stones?
Yes. Shih Tzus, miniature schnauzers, Yorkshire terriers, and Labrador retrievers have a higher risk of struvite stones. Dalmatians, Jack Russell Terriers, and Bulldogs have a higher risk of urate stones. Keeshonds, Norwich terriers, and Pomeranians are more prone to calcium oxalate stones.