Urolithiasis is a condition that causes urinary calculi or, bladder stones in dogs. These stones are actually minerals, which are excreted through the urine as tiny individual crystals or sand-like grains. Once these crystals are present, other minerals will continue to attach to their surface, turning these small tiny structures into stones that can be anywhere from 3 to 4 inches in diameter. They’re called bladder stones and while it’s true that 85% of stones are found within the bladder, they can also be found in the kidneys, ureters, urethra, or any part of the urinary tract.

There are different types of bladder stones, mostly dependent on what minerals make up the actual stone. Struvite stones are made up of magnesium ammonium phosphate, while others are formed from calcium oxalate, calcium phosphate, cysteine, and ammonium urate. The type of bladder stones will depend on the breed of the dog and different factors that led to the formation of the stone in the first place.

Causes of Bladder Stones in Dogs

Because of how bladder stones are formed, they can be found in dogs of any breed or any age. However, there are four main factors that have been found to be major influences on the development of stones in some dogs more than others. These are: genetics, concentration of the minerals found in the stones, the pH level of the urine, and bacterial infections.

• Genetics: Although there isn’t currently any testing to determine which type of breeds are most at risk for bladder stones, genetics has been found to be a factor. Some family lines simply have higher levels of certain substances that cause stones to be excreted from the urine.
• Concentration of minerals found in stones: The higher the mineral concentration found within the urine, the higher the likelihood that stones will form. These minerals can come from things such as diet, and the amount of water consumed throughout the day.
• Urine pH levels: While minerals sometimes form into stones, others often just dissolve. If the pH level of the urine is unbalanced, or if the urine is too high in acidity or alkalinity, bladder stones may form.
• Bacterial infections: Bladder stones can often be caused by bladder infections. This is because the bacteria that cause the infection, cystitis, also produces an enzyme called urease. This enzyme reacts with substances found in the urine to start a chain reaction that causes the stones to form. Bacterial infections can also cause the urine to become higher in alkalinity, which can also cause stones to form.

Symptoms of Bladder Stones

A very common sign that bladder stones are present is that the dog strains to urinate, a condition known as dysuria. This occurs when the walls of the urinary tract become inflamed and swollen. This can be caused from muscle spasms or stones that are so large they’re blocking the flow of urine from the bladder to the urethra. If the stones are partially obstructing this flow, the dog may only relieve very small amounts at a time, and they may try often.

If the stones are completely obstructing the urethra, the dog won’t be able to pass urine at all. If this happens, immediate emergency treatment might be needed to prevent the bladder from rupturing.

Diagnosing Bladder Stones

Bladder stones are sometimes found during a physical examination, even if the dog hasn’t shown any signs or symptoms at all. Abdominal x-rays are sometimes also done, although bladder stones don’t always show up on the films. If the stones are radiolucent, meaning that the x-rays pass right through them as though they’re invisible, a special dye will be passed into the bladder. After that, another x-ray will be done and the stones will show up.

Once it’s been determined that bladder stones are present, the vet will then likely perform a urinalysis to determine the pH level of the urine, along with which type of stones are being formed. This will help determine how to proceed with treatment.

Treatment of Bladder Stones

There are multiple forms of treatment for bladder stones in dogs, and the type your dog receives will depend on the type of stones that are present. Diet alteration is the simplest treatment but often, it dissolves even the largest stones. Sometimes medication may need to be prescribed and in the most severe cases, surgery may have to be performed.

Special diets have been developed for dogs suffering from bladder stones. They often involve wet food that has fewer minerals that are likely to cause the stones to form. These diets can be incredibly effective, but they can take anywhere from 60 to 150 days to work. Because it’s not recommended that dogs stay on these diets for long periods of time, the dog will typically need to stop the diet after that time and if the stones are still present, further treatment will be needed.

Increasing water consumption is often recommended for any dog suffering from bladder stones. Always make sure your dog is offered fresh clean water, and also consider adding water or broth to their dry food.

Antibiotics can also help treat bladder stones. Not only can they also help dissolve the crystals, they can also clear up any underlying infection, which will in turn get rid of the stones.

If the stones are blocking the passage of urine, the vet may perform an urohydropropulsion. While the dog is under anesthesia, the vet will try to flush the stones back into the bladder to allow the urine to pass through or, fill the bladder with a saline solution before forcing it out and along with the stones. If this still doesn’t clear the blockage, surgery will need to be performed so that the vet can manually remove the stones.

Bladder stones in dogs can be very troubling, and it can be painful to watch your dog go through it. Always keep an eye on your dog to make sure they’re not having any trouble urinating, and take your pet in at the first sign of trouble. If left untreated the effects of bladder stones can be disastrous, but if your dog receives medical attention right away, they are typically very easy to treat.