Acute renal failure after exercise in a child with renal hypouricaemia.

We describe a 12-year-old boy with renal hypouricaemia who presented with acute renal failure after a 6-h sports training session. Back and loin pain were noted at presentation. Although serum creatinine and blood urea nitrogen were elevated, the serum uric acid concentration was normal (2.6 mg/dl). This decreased to 0.3 mg/dl after recovery. The pyrazinamide and probenecid tests revealed that the cause of renal hypouricaemia in this patient was totally defective uric acid reabsorption. Acute renal failure after exercise is a rare but serious complication in paediatric patients with renal hypouricaemia.