ON THE DIAGNOSIS OF SYMPTOMATIC NEONATAL HYPOGLYCEMIA

Eighteen newborn infants, 11 males and 7 females, with hypoglycemia, i.e. with blood glucose concentration of less than 20 mg per 100 ml were studied. Twelve infants were diagnosed as cases of symptomatic and 6 as cases of asymptomatic hypoglycemia. All infants with asymptomatic hypoglycemia were small for gestational age, whereas the symptomatic group was heterogenous from a clinical point of view. The disappearance rate of intravenously administered glucose (k_G-value) was studied before any treatment was started. The k_G-values were high in all infants with symptomatic hypoglycemia, in 10 exceeding +2 s.D. for normal infants of the same age. The symptomatic infants were treated with hydrocortisone or human growth hormone in addition to continuous glucose infusion. After the institution of therapy there was a rapid normalization of the k_G-values. The 6 infants with asymptomatic hypoglycemia had normal k_G;-values. They were only given a high caloric supply by means of breast milk. In two infants with symptomatic hypoglycemia repeated simultaneous determinations of k_G-values and the plasma concentration of free fatty acids revealed no relationship. At follow-up examinations at ages from 5 months to 2 years, 2 out of the 12 infants in the symptomatic group were found to have severe cerebral damage. All infants with asymptomatic hypoglycemia were completely normal. The findings seem to have some clinical applications. Determination of the disappearance rate of intravenously administered glucose, primarily given as a diagnostic test, may differentiate between symptomatic and asymptomatic hypoglycemia. If in a doubtful case the k_G-value is normal, the likely diagnosis is asymptomatic hypoglycemia. In cases of symptomatic neonatal hypoglycemia repeated determinations of the k_G-value may provide a sensitive guide as to the effect of treatment.