Bladder stone formation, urolithiasis, happens anywhere in the urinary tract but primarily in the bladder. Causes of bladder stones are genetics, infections, metabolic disorders, medications and some diseases. Signs your dog has stones include blood in urine, urinating frequently, taking longer to urinate or straining without much urine released. Occasionally your dog may show no symptoms but the stones are felt by your vet during an exam. They can be painful and life threatening for your dog and need to be treated.
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Urohydropulsion
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If your dog has small stones that can pass through the urethra, the vet can anesthetize, insert a urinary catheter, flush sterile saline into the bladder and squeeze the bladder to help flush the stones out.
Stone Removal
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If stones are blocking so urine cannot escape, this can cause the kidneys to stop working and kill your dog. Often an attempt is made to back-flush the stones into the bladder. If that doesn't work, ultrasonic waves may be used to break up the stones. Most veterinarians do not have ultrasonic equipment, so surgery (cystotomy) to remove the stones is often the only solution. The stones are analyzed to determine their type.
Diet
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Small struvite and ammonium urate stones that are not causing blockage may respond to diets and be eliminated without surgery. Treatment can take two to five months to work. Prescription dog foods limit proteins, magnesium and phosphorous, which decrease chemicals in the urine that help form stones. Some also increase sodium so your dog drinks and urinates more to help flush small stones out before they enlarge.
Medications
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Antibiotics are important to control infections that cause stones. Other medications help balance pH levels. Acetohydroxamic acid is given to reduce stone formations from ammonium and carbon dioxide molecules. Potassium citrate causes calcium to stick to it instead of form stones and helps make urine alkaline to decrease stone formation. Thiazide diuretics may be given to increase urine and decrease calcium concentration.
Prevention With Diet
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Once the existing stones are eliminated, it is important to help your dog avoid forming new stones. Wendy C. Brooks, DVM, says the prevention of new stones relies on changing the urinary environment. For some kinds of stones, such as calcium oxalate, controlling pH while decreasing calcium and oxalate, prescription diets or homemade diets may help.
Increasing Water Consumption
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The more water your dog drinks, the better its bladder will flush to prevent stones. You can help increase water intake by using broths, soaking kibble in water or asking your veterinarian about sodium increase.
Avoiding Medications
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If your dog has a history of bladder stones, certain medications may increase the chance of future stones. Prednisone, non-Thiazide diuretics and vitamins D and C are some examples that may cause your dog to form stones.
Keeping Watch
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If your dog has oxalate stones or recurring incidences, the University of Minnesota recommends that a urinalysis is done every two months for life. Radiographs every three to six months may be needed to find and deal with small stones before they can cause blockage. For other types of stones, routine urinalysis is still recommended for up to a year.
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