Urinary crystals are commonly referred to as bladder stones or urinary calculi in dogs, and the condition which causes them is called urolithiasis. Urinary crystals are usually found within the bladder, but can form in the kidneys or surrounding tubes called ureters or the urethra. They are formed by minerals which are microscopic at first, but may join together to form sand-like grains that could continue to grow up to 3 to 4 inches in diameter. When these stones first begin to materialize, they are easy to pass, but become more difficult as they grow in size, and may obstruct the urinary passageway if they become too large.
Types of Urinary Crystals
Many different types of urinary crystals can form depending upon the chemical makeup of the substance. Struvite stones are made up of magnesium ammonium phosphate, and other common types include calcium phosphate, cystine, ammonium urate or calcium oxalate. Certain types of crystals are more common in certain breeds. Bacterial infections are a common cause of urinary crystals, as is urine which is high in alkalinity or acidity. Genetics may also play a role.
Symptoms of Urinary Crystals in Dogs
Frequent urination with possible blood in the urine can be a sign that your dog has urinary crystals. At other times, there will be no symptoms at all, and stones or crystals will be discovered during examination for other reasons. If you notice your dog straining to urinate, holding that particular position for longer than normal or licking the genitals in an excessive way, these may be indications. Abdominal x-rays can be performed for confirmation, and most crystals will show up as white circles or shapes. Radiolucent stones will not show up during x-ray and if these types of stones are suspected, a special dye will be passed into the bladder.
Treatment of Urinary Crystals
Several types of treatment are available for removal of urinary crystals, and choices will depend upon the location, size and type of the stones. The types of stones most often successfully treated with dietary management are struvite and ammonium urate stones. With the presence of some types of stones, such as with struvite, it is also important to control urinary tract infections as these will lead to the continued formation of urinary crystals. For certain stones, such as those formed by calcium oxalate, surgery may be the only option, but urohydropropulsion may be an option as well.
Urohydropropulsion
One of the treatment options for certain types of urinary crystals is called urohydropropulsion. Under anesthetization, a catheter will be inserted into the dog's urinary tract. The dog's bladder will then be filled with a sterile saline solution and will be compressed to force the solution back out. This method is only used when stones are verified to be small enough to pass through the urethra. If obstructions are present due to urinary crystals which are sizeable in nature, common in male dogs, a backflush can be performed before expelling the contents of the bladder. If this is not successful, an incision will need to be made for removal of the crystals blocking the urethra.