Canine Bladder Stones
By Tess Thompson Although there are other causes as well, dogs that do not drink enough water or those that are not allowed to urinate frequently are at a greater risk of forming bladder stones. Diet plays an important role since excess amounts of magnesium, calcium or phosphorus can lead to the formation of bladder stones. Other causative factors are the pH balance and urinary tract infection. In dogs urine normally tends to be more acidic. Stones of different composition of minerals can form in both acidic and alkaline urine. Many medications like diuretics, cortisone, sulpha drugs and tetracycline increase calcium levels in the urine that sets the stage for the formation of crystals and stones. Ammonium urate bladder stones are also among the many consequences of a liver shunt, a condition of abnormal blood flow to the liver. The treatment of canine bladder stones depends upon the type, size and composition of the stones. Almost fifty percent of the bladder stones are struvite and are predominantly found in female dogs. Excessive struvite crystals are normally formed due to urinary tract infection. In cats struvite stones are more common and are normally seen in housecats. Bacterial infection hydrolyses urea into ammonia and raises the urine pH to neutral or alkaline. Antibiotic therapy based on the type of bacteria and diuretics for flushing out urine help to resolve the problem. The second most common type of bladder stones in dogs is calcium oxalate. These are mostly caused by increased levels of calcium in the blood stream. The only treatment available for these types of bladder stones is surgical removal. Ammonium urate stones are normally treated with allopurinol that checks the excessive formation of uric acid. Many stones can be dissolved by feeding the dog with a special diet that ensures a reduced amount of certain minerals and proteins. A diet that effects urine pH and helps in increased urination to flush out the bladder is most effective. For some types and sizes of bladder stones, surgery may be the only treatment option. Surgical removal of bladder stones is called cystotomy. It usually is successful in resolving the issue and providing relief from canine and feline urinary incontinence issues too. However, surgery is only the first step since stones are prone to recur. A struvite stone can recur within two weeks of being infected with bacterium that is urease positive. Lifelong medication and increased attention to the type of diet is required even after surgery to ensure that the problem does not occur again.
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