Hyperuricosuria and increased tubular secretion of urate in sickle cell anemia

Abstract

Seven young adults with uric acid overproduction due to sickle cell anemia were normouricemic with a mean serum uric acid level of 4.9 mg/100 ml. Urate clearance was greater in these patients than in normal subjects or in patients with primary hyperuricemia due to uric acid overproduction. The increase in urate clearance was entirely accounted for by increased pyrazinamide suppressible urate clearance. Pyrazinamide administration abolished the uricosuric response to ribonucleic acid (RNA) feeding in these patients with sickle cell anemia, and maximal uricosuric response to the administration of probenecid was similar in the patients with sickle cell anemia and in normal subjects suggesting that reabsorption of both filtered and secreted urate was not impaired in sickle cell disease. Pyrazinamide suppressible urate clearance at maximal uricosuric response to probenecid was increased in patients with sickle cell disease suggesting increased tubular secretion of urate. This increase in urate secretion permits most young adults with urate overproduction due to sickle cell anemia to remain normouricemic and may account for the low frequency of secondary gout in this disease.