Neural dysfunction during hypoglycaemia.

There is controversy over the definition of hypoglycaemia in neonates and children and over its significance when 'asymptomatic'. We measured sensory evoked potentials in relation to blood glucose concentration in 17 children: 13 were fasted or given insulin to investigate endocrine or metabolic abnormalities and four had spontaneous episodes of hypoglycaemia. Abnormal evoked potentials were recorded in 10 of the 11 children whose blood glucose concentration fell below 2.6 mmol/l; five of these 10 children were 'asymptomatic'. No change in evoked potentials was recorded in the six children whose blood glucose concentration remained above 2.6 mmol/l. Our findings suggest that the blood glucose concentration should be maintained above 2.6 mmol/l to ensure normal neural function in children irrespective of the presence or absence of abnormal clinical signs.