Bladder Stones in Dogs

dog laying on pavement

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Bladder stones are common problems for many pets including cats, guinea pigs, and dogs. These stones can cause bladder issues such as pain, inflammation, bleeding, infection, trouble urinating, and in severe cases, complete inability to urinate, which is a life-threatening emergency. So, while they may be common problems, they are also serious issues. Preventative measures can be taken for dogs prone to developing stones, and various treatment options exist for dogs diagnosed with bladder stones, depending on the type of stone that has formed. By learning more about bladder stones, dog owners may be able to help prevent them from forming, know how to recognize the signs and symptoms in their dog if they do, and understand the treatment options that are available to them.

What Are Bladder Stones in Dogs?

Bladder stones, or uroliths as they are technically referred to, are hard, stone-like items that form within the bladder of a dog. These stones can be made up of various minerals, form a variety shapes, and may be associated with bacteria, crystals, and sludge. There can be one or many bladder stones within a dog's bladder and they can grow to be very large or stay very tiny. They are different from kidney stones since they form inside the bladder and not the kidney of a dog.

X-ray of a dog with bladder stones
Most bladder stones will be visible inside a dog's bladder on an X-ray. rarinlee/Getty Images

Types of Bladder Stones in Dogs

There are several different types of bladder stones that dogs commonly get.

  • Struvite stones: Struvites are also referred to as triple phosphate or magnesium phosphate stones and are usually smooth, pyramidal, and white bladder stones. Dissolved struvite is a normal part of a dog's urine but when changes in the urine occur (often as a result of bacterial infection), it can lead to the creation of stones. These stones are the most commonly seen type in dogs.
  • Calcium oxalate stones: Almost as common as struvites, calcium oxalates are bladder stones that affect a large number of dogs. These stones can vary in color from white to dark and are heavily textured.
  • Urate stones: Urate stones are not very common but are seen in certain populations of dogs. For example, Dalmatians are genetically predisposed to developing urate stones.
  • Cystine stones: One of the more rare types of bladder stones, cystine stones are usually seen in male dogs. This stone is textured and can vary in color.
  • Silica stones: Resembling a jack, silica stones are another rare type of bladder stone in dogs.

Symptoms of Bladder Stones in Dogs

Symptoms of Bladder Stones in Dogs

  • Blood in the urine
  • Licking at urinary tract opening
  • Crying when urinating
  • Straining when urinating
  • Frequent urination
  • Inappropriate urination

When a dog has a urinary issue, they often exhibit signs and symptoms of discomfort and trouble urinating. Licking at the urinary tract opening is an indication that something might be uncomfortable or painful in that region and straining or crying while urinating may also be seen in dogs with bladder stones. Frequent urination or urinating in the house may also be seen in dogs with bladder stones because of the pain or discomfort they are feeling. Even if their bladders aren't full, dogs may feel like they need to urinate. In rare cases, dogs may become completely unable to urinate, which is a life threatening emergency.

One of the most obvious signs that a dog has bladder stones is blood in the urine, but other health problems can cause this symptom as well. When bladder stones irritate the bladder wall, blood is released into the urine. Sometimes blood clots are observed but other times the urine is pink or red due to the presence of the red blood cells. If there is snow on the ground where your dog urinates, it will make this symptom all the more obvious.

Causes of Bladder Stones in Dogs

Depending on the type of bladder stone a dog has, the causes may vary.

  • Struvite stones: Because dissolved struvite is normally present in the urine of dogs, if the pH of the urine changes (becomes alkaline) due to the activity of bacteria and the urine becomes concentrated, this struvite might precipitate and form crystals. These crystals can then combine to form stones.
  • Calcium oxalate stones: A very acidic urinary pH and the presence of high levels of calcium, citrates, or oxalates causes calcium oxalate crystals to form which then turn into stones. There may be other causes as well; the formation of these stones is not fully understood.
  • Urate stones: These stones are often linked to a genetic abnormality that affects the normal metabolism of uric acid in dogs.
  • Cystine stones: These stones are thought to be linked to a variety of genetic abnormalities.
  • Silica stones: Various dietary factors like high levels of corn gluten feed or grain hulls, are thought to cause silica stones to form.

How to Diagnose Bladder Stones in Dogs

X-rays are the most commonly utilized diagnostic tool that veterinarians use to confirm a dog has bladder stones. Since bladder stones are mineral-containing items, they often reflect the X-rays and show up as white objects inside your dog's bladder. A small percentage of bladder stones, such as urate stones or any stone that is tiny, do not reflect X-rays well and show up best on an ultrasound.

Your veterinarian may also suspect that you dog has or is at risk for stones based on the presence of crystals (struvite or calcium oxalate, for example) in a fresh sample of urine. These crystals may be seen when urine is looked at under a microscope during a urinalysis.

Risk Factors for Dogs to Develop Bladder Stones

Some dogs are more likely to develop bladder stones than others. For example, dalmatians, English bulldogs, and individuals with some types of liver disease are more likely to develop urate stones than other dogs. Female dogs of all breeds are more likely than males to develop struvite stones, but males are more likely than females to develop calcium oxalate stones. Dogs with urinary tract infections are more likely to develop struvite stones than dogs without urinary tract infections.

Shih tzus, yorkies, bichon frises, lhasa apsos, and miniature schnauzers are at risk for developing struvite or calcium oxalate stones, and German shepherds and Old English Sheepdogs (among other breeds) are more likely to develop silica stones than other dogs. Dogs who have family members that have developed cystine stones are more likely than others to develop them themselves.

Any dog that has a history of bladder stones should be considered at high risk for a reoccurrence.

Treatment in Dogs

Dietary changes and medications to dissolve the stones may be recommended by your veterinarian depending on what type of stone is present in your dog's bladder. Struvite stones are the most common type of stone that can be dissolved by feeding a special diet.

Surgery to remove the stones is the most commonly used treatment for bladder stones that cannot be dissolved. Ultrasonically breaking apart stones is an option in some cases. It is available in specialty veterinary hospitals. Once broken up into small enough pieces, the stones can then be flushed out through the urinary tract opening.

Flushing very small stones out of the bladder with saline may also be done. Some stones are small enough to pass through the urinary tract opening without having to break them up with ultrasonic dissolution so your veterinarian may be able to remove them using a catheter and saline to flush them out of the bladder.

How to Prevent Bladder Stones in Dogs

If you have a dog that is at increased risk for bladder stones, your veterinarian may recommend feeding a special diet that is designed to decrease stone development. They will also recommend increasing fluid intake to encourage regular urination and decrease urine concentration.

Finally, if a dog has a history of a stone that has been linked to a genetic abnormality, that dog should not be used for breeding purposes.