[Efficacy of rasburicase therapy in obstructive renal failure secondary to urolithiasis: a novel therapeutic option].

The overall incidence of nephrolithiasis-related acute and chronic renal failure is poorly known and surely underestimated. However, obstructive nephropathy represents a potentially curable form of kidney disease that often requires for managing an instrumentation of urinary tract. Rasburicase is an enzyme that transforms uric acid to allantoin, a compound more water soluble that will be excreted by the kidney more easily. Rasburicase has been proven to be an effective therapy for prevention of tumour lysis syndrome. But it also represents an interesting new option in managing hyperuricemia in patients with severe tophaceous gout. We administered rasburicase intravenously (0.20 mg/kg/day, for 2 days) in 2 adults with acute obstructive nephropathy from renal calculi, which was receiving temporary haemodialysis. Rasburicase produced a sharp polyuria 12-18 hours after its administration accompanied with a fast reduction of serum creatinine levels, that returned to normal range without further dialysis. If we suppose that rasburicase can pass through glomerular filter by its relatively low molecular weight, it could dissolve tubular uric acid crystals in acute renal failure associated to tumour lysis syndrome, providing the restoration of renal function. But we also could postulate that rasburicase can act in urinary tract, fragmentating renal calculi, promoting relief of obstructive uropathy and the resolution of renal failure. We suggest rasburicase should be tried in this new indication to prove its potential efficacy.