IMPE Abstracts

Background: Congenital hyperinsulinism (CHI) is characterized by often severe hyperinsulinemic hypoglycemia due to pancreatic beta cell hypersecretion of insulin. Treatment delay confers a high risk of neurodevelopmental impairment (NDI).

Methods: We performed a single-center retrospective review of medical records of CHI-patients with EEG recordings, with addition of a blinded, quantitative EEG-analysis with age-matched healthy controls.

Results: EEG recordings were performed in 56/151 (37%) patients with verified hyperinsulinism. Fourteen (25%) had abnormal EEG during normoglycemia. Abnormal vs. normal EEG was correlated to NDI (P<0.001). Seven patients with abnormal EEG and two with normal EEG were diagnosed with epilepsy at discharge (abnormal vs. normal EEG, P<0.001). Reclassification of epilepsy diagnosis was seen in 20% (n=11). Country of origin, age, gender, gene mutations, histological type of CHI, brain magnetic resonance imaging, and blood glucose (BG) <24 hours (h) prior to EEG were not statistically associated with abnormal EEG. One patient had low BG (2.3 mmol/L <1h) prior to abnormal EEG, but a normal repeat EEG with prior BG of 3.6 mmol/L, indicating recent hypoglycemia-induced EEG changes at first EEG. In the quantitative EEG-analysis, CHI-patients with abnormal EEG had lower mean dominant frequency (P<0.001), higher relative delta power (P<0.001), and lower relative theta power (P<0.01), compared to controls, whereas CHI-patients with normal EEG did not differ from controls.

Conclusion: Abnormal EEG at normal BG was frequent, including epileptiform changes not necessarily associated with epilepsy. Recent hypoglycemia may induce abnormal EEG, reversible after BG normalization. Reclassification of the epilepsy diagnosis was frequent upon evaluation. Quantitative EEG changes with signs of diffuse cerebral impact may be due to earlier hypoglycemic episodes.