Hypoglycaemia in childhood.

HYPOGLYCAEMIA in children may cause listlessness, inattention, pallor, stupor, convulsions and coma, which may be accompanied by tachycardia and sweating. Such non-specific symptoms as cyanotic attacks, reluctance to feed, irritability, convulsions, jittery limb movements and depression of the Moro reflex may occur in the hypoglycaemic newborn infant. A major part of these clinical patterns arises from the neuroglycopenia which is caused by hypoglycaemia. Hypoglycaemia has been recognised in childhood for over forty years (Ross and Josephs, 1924) and yet its true incidence in the newborn and older child is still difficult to assess today. Forty cases occurred amongst children of all ages in a one hundred and thirty bed unit over a twelve year period (McQuarrie, 1954) and twelve neonatal cases were found among six thousand newborn infants (Neligan, Robson and Walton, 1963). The incidence of symptomatic hypoglycaemia has been found to be no less than 6% among premature infants, and as high as 15% in infants of birth weight less than the fiftieth percentile for gestational age (Wybregt, Reisner, Patel, Nellhaus and Comblath, 1964). Many different methods of blood sugar estimation have been used, and early less specific reduction methods (Folin and Wu 1920; Hagedorn and Jensen, 1923) tended to give higher figures than more specific reduction methods (Somogyi, 1952) and the glucose oxidase method (Marks, 1959). It is therefore difficult to define hypoglycaemia in terms of a blood glucose level. There is little doubt that the threshold for symptoms of neuroglycopenia varies from patient and from time to time. In the newborn a blood glucose level of under 20 mg./ 100 ml. or even below 10 mg./100 ml. may occasionally occur without symptoms, and many older children are not affected unless the level is under 40 mg./100 ml. Endocrine deficiencies causing hypoglycaemia are rare in childhood. Fasting hypoglycaemia was found in 29.3% of seventy-five cases of hypopituitarism, and hypoglycaemic symptoms occured in 9.7 %. In 37.5% of this series hypoglycaemia followed a glucose load and 66.7% were sensitive to insulin (Brasel, Wright, Wilkins and Blizzard, 1965). The T. P. MANN, M.D., F.R.C.P. Royal Alexandra Hospital for Sick Children, Brighton