Abnormal electroencephalogram at diagnosis of insulin-dependent diabetes mellitus may predict severe symptoms of hypoglycemia in children.

Abstract

To evaluate the predictive value of the electroencephalogram (EEG) at the time of diagnosis of insulin-dependent diabetes mellitus (IDDM) for subsequent hypoglycemic coma and/or convulsion. To study whether such an episode causes long-term EEG abnormalities. An EEG was recorded in 36 patients with IDDM 2 to 3 weeks after diagnosis (median age, 7.5 years) and was then repeated after an episode of severe hypoglycemia associated with coma and/or convulsion (median age, 13.3 years). Paired EEGs were also recorded in 36 age-matched and IDDM duration-matched control patients who had never experienced severe hypoglycemia. A single EEG was recorded in 36 healthy children, matched with patients' ages at the time of IDDM diagnosis. Patients with severe hypoglycemia had an abnormal initial EEG recording more often than did control patients with IDDM (22.2% vs 2.8%, P =.03). Each of the healthy children had a normal EEG recording. The odds ratio for risk of subsequent coma and/or convulsion during hypoglycemia in patients with abnormal initial EEG recordings was 8 (95% CI, 1.1-354.7). After such an episode, the frequency of the abnormal EEG recordings was not elevated. EEG at the time of diagnosis of IDDM may be useful in identifying those patients at increased risk for coma and/or convulsion as a result of hypoglycemia. However, a single such episode did not appear to have a deleterious effect on the subsequent EEG.