Hemiconvulsion-hemiplegia-epilepsy syndrome: early magnetic resonance imaging findings and neuroradiological follow-up

We describe a case of hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome documented by longitudinal magnetic resonance imaging (MRI). A two-year and nine-month-old boy had a prolonged hemiconvulsion during fever followed by right hemiparesis. Seven days later the imaging abnormality on T2 and diffusion-weighted images (DWI) was limited to the white matter of the left hemisphere. One month later severe gliosis and unilateral brain atrophy were already evident. MRI is useful in the early stages of prolonged seizures and T2 and DWI abnormalities appear to be well correlated with parenchymal damage that results from sustained ictal activity. The neuroradiological findings in our case and in the few HHE patients reported in the literature seem to be very characteristic and, if confirmed in larger series, could permit an early diagnosis.