Overview of Urate Urolithiasis in Dogs
Urate uroliths, also referred to as calculi, are stones within the urinary tract composed of ammonium urate. Urate uroliths are commonly referred to as bladder stones made of urate. Dalmatians and English bulldogs are at highest risk due to inborn metabolic abnormalities and miniature schnauzers and Yorkshire terriers are at high risk due to their predisposition to portosystemic shunts. The average age of onset for dogs with portosystemic shunts is less than one year, whereas the average age of onset for dogs without portosystemic shunts is greater than three years of age.
Clinical symptoms depend on the size and number of uroliths as well as their location within the urinary tract. Some affected animals may have no clinical symptoms.
Causes of Urate Urolithiasis in Dogs
What to Watch For
Signs of urate urolithiasis in dogs may include:
Occasionally, nervous system abnormalities (dull mental attitude, head-pressing, seizures) may be observed in animals with portosystemic shunts.
Inability to urinate may be seen in animals with urethral obstruction. Urethral obstruction constitutes a medical emergency and you should take your pet immediately to your veterinarian.
Diagnosis of Urate Urolithiasis in Dogs
Routine tests include a complete blood count (CBC), biochemical profile and urinalysis. Changes such as low blood urea nitrogen (BUN), low blood sugar, and low protein concentrations may be seen in animals with portosystemic shunts. Kidney impairment (high BUN and serum creatinine concentrations) may be seen in animals with urinary tract obstruction or related kidney disease. Urate crystals are present in the urine in some but not all cases. Also, urate crystals are seen commonly in the urine of normal Dalmatian dogs.
Additional tests include:
Treatment of Urate Urolithiasis in Dogs
It is important to establish whether or not the affected dog in need of emergency care or hospitalization. Examples of emergency situations include animals with urethral obstruction, severe kidney failure, and those with hepatic encephalopathy, which are nervous system signs secondary to a portosystemic shunt.
Surgical intervention depends upon the location and size of the calculi, in addition to the clinical symptoms present in the patient. In addition, surgical repair may be warranted in pets with portosystemic shunts.
Additional treatment includes:
Home Care and Prevention
Administer as directed all medications prescribed by your veterinarian. Also, follow dietary and feeding recommendations and follow up with your veterinarian as directed. Recurrence of urate urolithiasis is common in dogs.
Consider special diets in those breeds with a predilection to urate calculi, specifically low protein alkalinizing diets that increase urine pH. If your pet is diagnosed with a portosystemic shunt, appropriate medical or surgical therapy should be instituted at once so as to reduce the risk of forming urate calculi.