Approach to the Neonate With Hypoglycemia

Abstract

After birth, healthy neonates undergo a period of altered glucose metabolism, known as "transitional hypoglycemia." During the first 0 to 4 hours of life, the mean plasma glucose concentration decreases to 57 mg/dL, then by 72 to 96 hours of life increases to 82 mg/dL, well within the normal adult range. Recent data suggest that transitional hypoglycemia is due to persistence of the fetal beta cell's lower threshold for insulin release, resulting in a transient hyperinsulinemic state. While hypoglycemia is an expected part of the transition to postnatal life, it makes the identification of infants with persistent hypoglycemia disorders challenging. Given the risk of neurologic injury from hypoglycemia, identifying these infants is critical. Hyperinsulinism is the most common cause of persistent hypoglycemia in neonates and infants and carries a high risk of neurocognitive dysfunction given the severity of the hypoglycemia and the inability to generate ketones, a critical alternative cerebral fuel. Screening neonates at risk for persistent hypoglycemia disorders and completing evaluations prior to hospital discharge is essential to prevent delayed diagnoses and neurologic damage.

Keywords: glucose; hyperinsulinism; hypoglycemia; ketones; neonate.

Figure 1.

Algorithm for the diagnosis of persistent hypoglycemia disorders based on the levels of lactate, ketones and free fatty acids at the time of hypoglycemia. Most common disorder(s) are listed for each category. Note that neonatal panhypopituitarism presents with suppressed ketones and free fatty acids.