Topography of brain damage in metabolic hypoglycaemia is determined by age at which hypoglycaemia occurred

Aim Having previously shown that comorbidity is a major determinant of neurological sequelae in hypoglycaemia, our aim was to describe the neuroimaging patterns of brain damage in different hypoglycaemic situations and to elucidate the factors that determine lesion topography. Method We reviewed 50 patients (31 females, 19 males) with symptomatic hypoglycaemia (<2.8mmol/L) occurring between 1 day and 5 years of age (median 4d) who had undergone magnetic resonance imaging (MRI; at least axial T2-weighted, sagittal T1-weighted, and coronal fluid-attenuated inversion recovery [FLAIR]-weighted imaging). MRI was performed during the follow-up examination at least 1 month after the occurrence of symptomatic hypoglycaemia, i.e. between 1 month and 5 years of age (median 3mo). Hypoglycaemia resulted from three inborn errors of metabolism: congenital hyperinsulinism (33 patients), fatty acid beta-oxidation disorders (13 patients), or glycogen storage disease type I (four patients). We selected the patients with clear MRI abnormalities and analysed their topography according to aetiology and age at occurrence of the lesion. Results The topography of the brain lesions depended on age: from the neonatal period to 6 months of age, lesions predominantly involved the posterior white matter; between 6 and 22 months the basal ganglia, and after 22 months the parietotemporal cortex (p=0.04). Interpretation The relationship between brain lesions and age could reflect the maturation sequence of the brain.