Diagnosis and treatment of hypoglycaemia in the newborn.

The importance of hypoglycaemia, defined as a true blood glucose below 20 mg./100 ml., in the newborn infant is now well recognized. It is sometimes found in the idiopathic respiratory distress syndrome (RDS), in infants of diabetic mothers, and in neonatal cold injury, and it may also occur in association with anoxia, cerebral haemorrhage, or infection (Neligan, 1965). The majority of symptomatic cases, however, are 'idiopathic', though there is an obvious clinical association with 'dysmaturity' and intrauterine deprivation (Brown and Wallis, 1963). Shelley and Neligan (1966) stressed the value of the therapeutic test of giving 1 to 3 g. glucose intravenously. Prompt disappearance of symptoms suggests that these were related to hypoglycaemia. An associated problem is the possible significance of asymptomatic hypoglycaemia in some infants. Routine measurement of true blood glucose levels in all premature, dysmature, and other 'at risk' infants imposes a heavy load on a laboratory. The 'Dextrostix' enzyme test strip for estimation of the blood glucose has provided a possible screening test for the presence of hypoglycaemia. In addition, 'Dextrostix' tests allow of more frequent checks during treatment of a proven case of hypoglycaemia. Initially, we used 'Dextrostix' only when symptoms suggested that an infant might be hypoglycaemic. Although the preliminary report on the use of 'Dextrostix' by Cohen, Legg, and Bird (1964) included very few readings where the true blood glucose was below 40 mg./100 ml., we have found that in all cases where the true blood glucose was below 20 mg./100 ml., the 'Dextrostix' recorded either less than 40 mg./100 ml., or 'doubtful'.