FAOD Fatty acid b-oxidation defect GSDI Glycogen storage disease type I 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 b-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.
RESULTSThe 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).
INTERPRETATIONThe relationship between brain lesions and age could reflect the maturation sequence of the brain.Hypoglycaemia is a cause of brain damage that particularly affects the neonate and infant.1,2 Damage is usually considered to involve the white matter of the posterior regions, 3 but the basal ganglia and cortex may also be affected. 4 The factors determining the topography of brain injury remain unknown. In a previous study focusing on inborn errors of metabolism that prevent the production of alternative sources of energy, we showed that, in addition to aetiology and prolonged convulsions, additional factors, namely hypoxia-ischaemia and infection, are the main determinants of neurological sequelae, whatever the age at the time of occurrence of the hypoglycaemia. 5 We now investigated how age, although not the main factor influencing neurological sequelae, affects the topography of brain lesions produced by hypoglycaemia.
METHODOf 169 patients who experienced hypoglycaemia due to three inborn errors of metabolism, all 50 with symptomatic hypoglycaemia with or without neurological sequelae underwent magnetic resonance imaging (MRI). Hypoglycaemia was defined as a plasma glucose level below 2.8mmol ⁄ L (Dextrostix followed by venous measure). Severe sequelae were considered to be global psychomotor delay, microcephaly, motor deficit, lack of visual contact, and ⁄ or pharmacoresistant epilepsy. Mild sequelae consisted of speech delay, learning difficulties, and pharmacosensitive epilepsy.
ParticipantsThis cohort study was a retrospective analysis of data from files,...