Bladder Stones in Dogs

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Bladder stones (otherwise known as cystic calculi) are a collection of minerals, ranging in size and composition, that can cause frequent urinary tract infections, pain, and obstruction of the urinary tract. However, sometimes dogs with bladder stones have no obvious clinical signs.

There are multiple causes of bladder stones, such as a change in urine acidity (pH), infection, calcium or phosphorus imbalances, and liver shunts. But in many cases, an inciting cause is never identified.

There are different types of stones, each formed from a complex mixture of minerals. Two of the most common are struvite (also known as magnesium-ammonium-phosphate or triple-phosphate) and calcium oxalate stones. Each type tends to develop under specific conditions.

While bladder stones are obviously found in the bladder, dogs will occasionally develop small stones in their kidneys or ureters (the small tube that carries urine from the kidney to the bladder). Unlike in people, kidney stones in dogs do not often require treatment. However, if a stone gets stuck in the ureter and causes a blockage, surgery or other advanced treatment may be needed to prevent irreparable kidney damage.

Signs and Symptoms of Bladder Stones in Dogs

Dogs with very small bladder stones will not always exhibit symptoms. Often, these small stones will pass through the urinary tract without being noticed, especially in female dogs. (Females have a much shorter and wider urethra than do males, making it much easier for stones to pass.) However, larger stones may interfere with urination or irritate the lining of the bladder or urethra. Signs and symptoms include:

  • Discomfort and difficulty urinating
  • Urinating small amounts very frequently
  • Blood in the urine
  • Cloudy or discolored urine
  • Bloated or sensitive stomach
  • Avoidance of exercise
  • Pain in the abdomen around the kidney area
  • Change in energy level
  • Vomiting

It’s important to note that not all of these symptoms may present themselves. Pain may be the only indicator that bladder stones are present, so it can be difficult to diagnose.

It’s nonetheless important to figure out if your dog is suffering from this ailment: if left untreated, stones can cause blockages, chronic urinary tract infections, and be potentially life-threatening.

How Did My Dog Get a Bladder Stones?

Veterinarians are not completely sure what causes stones to form, but different factors such as genetic and environmental issues can play a part in their development and recurrence.

Some facts to consider:

  • Vitamins and minerals are important to a healthy, balanced diet, but in some cases a canine diet high in minerals can actually cause or worsen bladder stones. It is very important never to give your dog a vitamin or mineral supplement without first checking with your veterinarian.
  • The pH balance of a dog’s urine is also an indicator of whether he may develop stones. If the pH level is too low, or too high, crystals will form and ultimately turn into stones. A dog’s pH levels can be controlled through diet.
  • Canine diabetes is another contributing factor. Dogs with this endocrine condition suffer from urinary tract infections, which can cause bladder stones.
  • Certain long-term medications may alter the pH levels in the urine and cause an increase in calcium, which can lead to the formation of stones.

There are two main types of stones.

Struvite stones develop when struvite crystals, which aren’t found in normal urine, combine with certain bacteria. The presence of struvite crystals alone do not require treatment, but when combined with an enzyme called urease, which certain bacteria can produce, stone formation is possible.

With calcium oxalate stones, there is a strong hereditary component. Certain dogs may be genetically predisposed to produce defective nephrocalcin, which is a substance in urine that naturally inhibits the formation of calcium oxalate stones. However, even dogs without a genetic propensity can still develop calcium stones.

There are also certain metabolic diseases that may predispose a dog to creating calcium oxalate stones. For instance, a dog with Cushing’s disease may produce higher levels of cortisone, a hormone that increases calcium excretion in urine. The extra calcium can lead to stone formation. An overactive parathyroid gland (hyperparathyroidism) can also affect calcium metabolism, resulting in the formation of calcium stones.

Diagnosing Bladder Stones in Dogs

Bladder stones can be detected in a few different ways. Very occasionally, a vet can assess the presence of stones simply by pressing on a dog’s abdomen. Stones may also be detected during a rectal examination or upon the attempted insertion of a urinary catheter. However, most bladder stones are diagnosed through x-rays or ultrasound. A urinalysis may also gives clues as to the presence of bladder stones.

It’s possible for more than one stone to be present; once one is located, the entire urinary tract should be examined.

Facts about struvite bladder stones:

  • 85% of dogs diagnosed with struvite stones are female
  • On average, dogs who develop struvite stones are 2 to 4 years of age
  • Breeds with an increased risk are Miniature Schnauzer, Shih Tzu, Yorkshire Terrier, Labrador Retriever, and the Dachshund

Facts about calcium oxalate stones:

  • 73% of dogs diagnosed with calcium oxalate stones are male
  • Most cases occur in dogs between the ages of 5 and 12 years old
  • Breeds with an increased risk are Miniature Schnauzer, Lhasa Apso, Shih Tzu, and Bichon Frise

The exact mineral composition of a bladder stone is determined by a “complete quantitative analysis.” This test requires submitting a bladder stone to an outside laboratory.

Treating Your Dog for Bladder Stones

Treatment for bladder stones depends largely on the type and location of the stone. Options include surgery, lithotripsy (a procedure that breaks apart the stones), a change in diet, and medication.

With struvite stones, there are multiple options to consider, each carrying pros and cons.

  • Surgery. Advantage: The stones are removed and healing begins immediately. Disadvantage: There are risks associated with surgery in general, including anesthesia, post-op pain, and risk of infection.
  • Urohydropropulsion (using a liquid solution in the bladder to expel the stones). Advantage: If the the stones are small enough, they can be maneuvered in a way to expel them through the urethra. This works only if the stones are small and the dog is not too large. Disadvantage: This procedure typically requires general anesthesia. It also requires a temporary urinalysis catheter, which increases the risk for infection.
  • Laser Lithotripsy. Advantage: If the stones are smaller, this procedure is a good alternative to surgery. Disadvantage: Because this procedure requires a specialist and specialized equipment, it can cost more than surgery.
  • Dietary Dissolution. Advantage: Several therapeutic diets are designed to dissolve struvite stones. This solution carries the lowest risk and is the most comfortable. Disadvantage: There’s a possibility that as the stone becomes smaller, it can get lodged in the urinary tract on its way out of the body. This can be potentially life-threatening for males due to their narrow urethras. These diets are also high in fat and salt and not appropriate for dogs with certain medical issues.

Unlike struvite stones, calcium oxalate stones cannot be dissolved through dietary changes. If they are tiny, flushing the bladder and forcefully expressing the stones may be possible; otherwise they will need to be surgically removed.

Is There a Cure for Bladder Stones?

Bladder stones can be removed in a number of ways, but there may not be a way to prevent them from forming in certain dogs. However, if your dog has been treated for bladder stones, your veterinarian may recommend a prescription diet to help prevent the formation of new stones.

Are Bladder Stones Contagious for Humans or Other Pets?

Bladder stones are not contagious.

What Is the Cost of Treating Bladder Stones?

The presence of bladder stones may require a variety of tests. For example, a urinalysis can run between $65–$175; x-rays anywhere from $50 and up; ultrasounds, $250 and up; bloodwork at least $100 or more. Considering that these are only diagnostic tests, the total cost for a case of bladder stones can be quite high.

Surgery starts around $700 and can run upwards of $1700, depending on the particular vet or specialist and your geographic location. Some offices charge separately for the anesthesia/sedation.

Post-surgery costs to consider are follow-up visits, medication, and possibly a prescription diet that your dog may need to remain on for the duration of his/her life.

Recovery and Management of Bladder Stones

The course of treatment can determine a dog’s recovery schedule.

While diet doesn’t play a key role in the formation of struvite stones, it does aid in treating them. Dietary dissolution of struvite stones can take two to three months, with a continuation of the diet for an additional month to ensure that even the smallest stones have dissolved. Long-term use of a prescription diet may be recommended to prevent the formation of new stones.

On the flip side, calcium oxalate stones cannot be treated through diet, although dietary management is important when it comes to preventing recurrence. Calcium oxalate stones typically require surgical removal.

While surgery entails more risk than dietary dissolution, the stones are removed more quickly and healing begins immediately.

Preventing Bladder Stones in Dogs

Complete prevention of bladder stones is difficult, but annual check-ups play an important role. In order to monitor your dog effectively, know the signs and symptoms associated with bladder stones. The right diet can help thwart the return of bladder stones, and water intake is very important, since problematic crystals are less likely to form in dilute urine.

Summary

Bladder stones in dogs can cause frequent urinary tract infections, pain, and blockages, which can be potentially fatal if untreated, so it’s important to contact your vet immediately if you suspect your dog may have a bladder stone.

Prevention is the best defense: observe your dog’s urination habits; feed him a proper, well-balanced diet; and ensure he has access to plenty of water at all times so he can flush out the bladder consistently.

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