Rasburicase for hyperuricemia in hemolytic uremic syndrome

Acute kidney injury (AKI) with elevated serum uric acid (UA) levels has been reported in patients with hemolytic uremic syndrome (HUS). AKI is thought to result from tubular obstruction by UA crystals. Inducing a diuresis may ameliorate the oligoanuria in such patients. We describe a child with HUS in whom reducing UA with fluids and rasburicase appeared to accelerate the recovery of renal function. A 9-month-old Caucasian male infant presented with 6 days of diarrhea, 3 days of vomiting, and 24 h of oliguria. On admission, hemoglobin was 8.3 g/dL, platelet count 36,000/L, blood urea nitrogen 73 mg/dL, and serum creatinine (SCr) 2.7 mg/dL. Diarrhea-associated HUS was diagnosed. The day after admission, SCr was 2.9 mg/dL and UA 12.3 mg/dL. On hospital day 2, he received a dose of intravenous rasburicase 0.18 mg/kg, and less than 12 h later, the UA had fallen to 0.3 mg/dL. The SCr level also started to fall, and urine output progressively increased without the use of diuretics. Renal function continued to improve, and the UA level remained normal despite ongoing hemolysis requiring a second red blood cell transfusion on hospital day 5. The patient was discharged on hospital day 7 in good physical condition. Two months later, he was in good health, with a SCr level of 0.2 mg/dL and UA of 4.2 mg/dL. We postulate that aggressive management of the high serum UA level with rasburicase and fluid hydration accelerated the recovery of our patient. Further studies are needed to determine the role of rasburicase in the treatment of hyperuricemia in patients with HUS.