Hyperammonemia in hypoglycemic preterm neonates.

Plasma glucose, blood urea nitrogen, and ammonia were measured simultaneously in 44 newborns a few hours after birth. When the concentration of plasma glucose was below 30 mg/dl, plasma ammonia concentration was significantly higher (129 +/- 67 mumol/l) than in normoglycemic infants (74 +/- 33 mumol/l; p less than 0.01). Blood urea nitrogen was slightly lower in hypoglycemic infants (3.65 +/- 0.7 mmol/l) than in the control group (4.5 +/- 1 mmol/l) but the difference was not significant. These data show that hyperammonemia can be associated to hypoglycemia in low birth weight infants. Therefore, further investigations are required to determine the link between urea and glucose production rates in hypoglycemic newborns and whether hyperammonemia participates in the deleterious effects of hypoglycemia on the neonatal brain.