What are the signs of bladder stones in dogs?

Bladder stones in dogs form when microscopic crystals in the urine cluster together over time to form a stone that is visible to the naked eye. There are many circumstances that can contribute to bladder stone formation in dogs. However, not all stones are dangerous or require treatment. Read on to learn:

• What bladder stones are and how they form
• Clinical signs of bladder stones in dogs
• When bladder stones are an emergency
• How canine bladder stones are diagnosed and treated

The treatment for bladder stones in dogs varies depending on the type, size, and number of stones as well as where in the bladder they’re located. Struvite and calcium oxalate stones, the two most common types of bladder stones in dogs, are treated differently.

Urinary stones, or uroliths, form when microscopic urinary crystals clump together to form larger formations visible to the naked eye. Uroliths can form anywhere in the urinary tract, but the vast majority of stones form in a dog’s urinary bladder. These are also known as urocystoliths. Kidney stones, or nephroliths, are rare in dogs.

Bladder stones can vary in size, number, and composition. Struvite stones and calcium oxalate stones are the most common types of stones that form in dogs. Though stones can affect any dog, females develop them more often than males, and some dog breeds are at a higher risk than others. Male dogs are more likely to develop urinary blockages from stones, which is an emergency complication.

How bladder stones form in dogs

In specific conditions, minerals separate out of the urine and clump together to form microscopic crystals. Over time, these crystals aggregate together and form larger stones that can be seen with the naked eye. Various risk factors affecting urine composition that can contribute to the formation of bladder stones include:

• Urinary tract infections
• Urine pH
• Urine concentration
• Mineral levels in the body
• Nutrient imbalances
• Metabolic abnormalities

The number of stones a dog develops varies, with some dogs having only one while others may have a few or even hundreds.

Struvite bladder stones usually form in response to changes in the urine from a bacterial infection in the bladder. Rarely, struvites may form as a result of:

• Side effect of some antacids and diuretics
• Hyperaldosteronism
• Hereditary condition found in English cocker spaniels

Any dog breed can develop struvite stones, but some breeds are more at risk of stone formation than others, including:

• Miniature schnauzers
• Shih tzus
• Yorkshire terriers
• Labrador retrievers
• Dachshunds

Genetics plays a significant role in the formation of calcium oxalate stones. In some breeds, a substance that prevents the formation of oxalates is defective. Other hereditary disorders predispose other breeds to calcium oxalate stone formation. Cushing's disease often increases excretion of calcium in the urine, so affected dogs are more likely to develop calcium oxalate stones. Most cases of calcium oxalate stones occur in adult male dogs.

“Bladder stones may cause no symptoms at all,” explains Dr. Jo Myers, a veterinarian on Vetster. “Small stones may be expelled in the urine without complications, and a large stone may stay in the bladder without causing any problems.” When present, clinical signs of stones in dogs may include:

• Blood in urine
• Frequent urination, often in small amounts
• Straining to urinate
• Dribbling urine or having accidents
• Painful urination or vocalizing when urinating
• Excessive licking of the genitals

Symptoms of bladder stones are similar to those of other urinary conditions. The only way to know if a dog has stones is to see a veterinarian for diagnostic testing.

When bladder stones are a medical emergency

Bladder stones are not emergencies themselves, but they can lead to emergency complications. If a stone becomes stuck in the urethra after it leaves the bladder when a dog urinates, the subsequent urinary obstruction is a medical emergency. Symptoms of a urethral obstruction in dogs include:

• Inability to urinate or straining unproductively
• Vocalizing in pain when trying to urinate
• Much smaller flow of urine than normal
• Vomiting
• Lethargy

A blockage in the urinary tract stops urine flow, causing urine to back up and toxins to accumulate. This is life-threatening and can quickly lead to kidney damage. A urinary blockage requires emergency treatment from a veterinarian.

Dogs presenting with urinary symptoms such as bloody urine and a frequent need to urinate usually receive a thorough physical examination and a urinalysis. Bladder stones may be suspected based on initial findings, but diagnostic imaging, such as X-rays or ultrasounds, is necessary to see them. Bloodwork and other diagnostic testing may also be recommended. Diagnostic testing is important to help vets understand the extent of the problem, such as:

• How many stones are present
• The size and shape of the stones
• Where in the bladder the stones are located
• The presence of contributing factors, such as infection

A urinalysis shows characteristics of the urine, such as urine pH and concentration, and includes microscopic examination for crystals, blood cells, and bacteria. Some bladder stones can be seen on X-rays and ultrasounds of the abdomen. A stone analysis to identify what kind of stone it is can help to determine the best course of treatment.

Effective treatment options for stones vary based on the mineral composition, size, location, and underlying cause of the stones. Some stones do not warrant treatment. Small stones can sometimes pass on their own, and some large stones can be left alone in the bladder as long as they’re not causing a problem. When necessary, treatment may include:

• Antibiotics for concurrent bacterial bladder infections
• Dietary management
• Increasing water intake
• Flushing small stones from the bladder and urethra (voiding hydropropulsion)
• Surgery
• Lithotripsy, or shock-wave therapy

Struvite bladder stones are often treated with dietary therapy to dissolve the stones, along with antibiotics if the dog also has a UTI. Medical dissolution of stones with a therapeutic diet takes time, so it may not be an option for dogs who need a quicker form of treatment.

Calcium oxalate stones cannot be dissolved with dietary therapy. Instead, they must be physically removed from the urinary tract with voiding hydropropulsion, surgery, or lithotripsy (shock-wave therapy). Voiding hydropropulsion involves filling the bladder with sterile saline through a urinary catheter and then squeezing the urinary bladder to expel small stones. If hydropropulsion does not work, surgical removal of the stones may be necessary.

Treatment for a urinary obstruction

If there’s an obstruction, it becomes the priority during treatment for bladder stones. Stones may be pushed back into the bladder using a urinary catheter, where they can then be surgically removed. If this doesn’t work, a vet may need to surgically remove the stones from the urethra. Dogs recovering from urinary blockages usually require hospitalization for a couple of days to receive IV fluids and antibiotics, and to ensure they’re urinating normally.

It’s important to talk to a veterinarian any time a dog displays urinary symptoms. Many urinary conditions share common symptoms, such as bloody urine, straining to urinate, and a frequent need to urinate. For effective treatment, the underlying condition needs to be correctly identified with diagnostic testing. A dog may have multiple urinary issues at once.

Seek care immediately if a dog is straining unproductively or producing a much smaller stream of urine than usual. These are signs of a potential urinary tract obstruction, which is a life-threatening emergency. Recurrence of urinary stones is common, so long-term management is important. If your dog is showing signs of a urinary condition, you can talk to a veterinary professional in a Vetster online virtual care appointment for advice.

What is the main cause of bladder stones in dogs?

The formation of bladder stones in dogs is not fully understood and is likely due to multiple factors. Changes in urine composition, diet, and hydration can all play a role in bladder stone formation in dogs. Stones can form due to a change in the urine’s pH, concentration, and mineral composition, as well as secondary to a bacterial bladder infection.

How do you get rid of bladder stones in dogs?

Treatment depends on the type of stone, how large it is, and where it’s located. Some canine bladder stones do not require treatment, while others may be treated with a diet change, antibiotics, surgery, or other treatment. It’s important to confirm the presence of urinary stones with a vet and work with a vet to treat them effectively.

Can tap water cause bladder stones in dogs?

There is currently no scientific evidence to support the claim that tap or hard water causes bladder stones in dogs. There is no need to purchase water softeners or bottled water for your dog unless directed to do so by a veterinarian. To learn more, talk to a local vet about your tap water.