Hyperammonemia in Hypoglycemic Preterm Neonates

Abstract

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 μmol/l) than in normoglycemic infants (74 ± 33 μmol/l; p < 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.

A Nationwide Survey on Transient Hyperammonemia in Newborn Infants in Japan: Prognosis of Life and Neurological Outcome

“…It is known that hypoglycemia mayaiso be associated with an elevated concentration of plasma ammonia in preterm neonates (20). There was no correlation between plasma ammonia concentration and blood glucose levels in our series.…”

Diagnosis of congenital hyperinsulinism: Biochemical profiles during hypoglycemia

“…In all of these, the hyperammonemia resolved subsequently. Although the exact mechanism leading to transient neonatal hyperammonemia is not known, it can be caused by hypoxemia per se . A false elevation of ammonia levels can also be caused by poor handling of blood samples.…”

Neonatal Hypoglycemia

“…We could observe hyperammonemia (> 100 H-Vf) in half of the low birth weight infants whose plasma glucose concentra tions were lower than 1.72 mA/ [2], This limit will be the definition of hypoglycemia which will be used subsequently. Recently, using sensory evoked potential (SEP) tech nics Koh et al [3] found abnormal patterns with plasma glucose concentrations lower than 2.6 mM.…”