Canine Urate Uroliths

• Performing diagnostic studies including contrast radiography to identify urolith size and location, as well as confirmation of urolith composition prior to attempting dissolution.
• Initiating therapy with calculolytic diet that promotes alkaluria, promotes diuresis, and is restricted in protein.
• Initiating therapy with allopurinol at a dosage of approximately 15mg/kg/every 12 hours orally.
• Monitor response to therapy at appropriate intervals.

To minimize stone recurrence or further growth, we recommend the following:

• Perform appropriate diagnostic studies to identify location and size of uroliths, or post-surgical radiographs to determine efficacy of surgical removal.
• Perform appropriate laboratory tests to determine if a portal vascular anomaly is the underlying cause for uroliths (eg. provocative serum bile acid tests).
• Provide diets that promote diuresis, alkaline urine, and are protein restricted.
• Encourage additional water consumption or feed a canned diet to promote diuresis.

If diet therapy alone is ineffective, some investigators further recommend long-term therapy with allopurinol at a dosage of approximately 10 to 20 mg/kg/day.  Recent studies indicate that prolonged administration of high doses of allopurinol may be a risk factor for formation of xanthine uroliths, especially when given in conjunction with high purine diets.
If uroliths should recur despite control of risk factors, they may be removed non-surgically by voiding urohydropropulsion if detected early.  Uroliths removed by voiding urohydropropulsion should be quantitatively analyzed.  If attempts at non-surgical urolith removal are unsuccessful, surgery remains the most reliable way to remove active uroliths from the urinary tract.  We emphasize, however, that surgery may be unnecessary for clinically inactive urate uroliths. 
All prevention recommendations should be adjusted to meet individual patient's needs.  We recommend follow-up urinalyses, serum chemistry profiles, and radiographs on a periodic basis.

Further  references:
Lulich JP, Osborne CA, Unger LK, et al:  Nonsurgical removal of urocystoliths by voiding urohydropropulsion.  In Journal of the American Veterinary Medical Association. Vol 203,  pp. 660-663, 1993
Osborne CA, et al.:  Canine and Feline Urolithiases:  Relationship of Etiopathogenesis to Treatment and Prevention.  In Canine and Feline Nephrology and Urology, Osborne and Finco 1995, pp 798-888.
Lulich JP, Osborne CA, Felice LJ, Bartges JW, Unger LK, Sanna JJ, Johnston GR:  Medical Management of Canine Ammonium Urate Urolithiasis.  In Managing Canine and Feline Urolithiasis.  Hills Pet Products pp 46-52, 1989.