Nephrocalcinosis and prematurity: importance of urate and oxalate excretion.

Nephrocalcinosis was described in preterm infants by several authors who tried to determine its association with hypercalciuria and furosemide therapy. We evaluated these potential mechanisms along with other lithogenic factors not previously studied in 10 premature babies. Hypercalciuria was an inconsistent finding like in other reports; elevated uric acid excretion and hyperoxaluria were observed in 5 and 6 cases, respectively. The aminocid excretion was normal in all infants. Our data suggest that in addition to hypercalciuria, other lithogenic factors may play a role in the pathophysiology of nephrocalcinosis of premature infants.