Neonatal hyperuricemia.

Serum concentrations and urinary excretion of uric acid were measured in ten normal newborn infants and in 13 patients with the idiopathic respiratory distress syndrome. In the normal infants, serum urate increased from a mean value of 6.0 mg/dl in cord blood to 7.0 mg/dl at 24 hours, followed by a decrease to 3.5 mg/dl over the next three days. The infants with IRDS had higher serum urate concentrations during the first three days of life, and the urinary excretion of uric acid over the period of 12 to 36 hours of age was also higher than in the normal infants. In both groups of neonates the correlation of maximal serum urate values with the urinary excretion was positive, which indicates that neonatal hyperuricemia is not due to renal retention but to increased production of uric acid. It is postulated that this overproduction results from increased nucleotide breakdown associated with perinatal hypoxia. Because of high serum and urinary uric acid concentrations, maintenance of adequate hydration and urinary flow as well as alkalinization of urine is recommended.