Elsevier

Brain and Development

Volume 29, Issue 2, March 2007, Pages 109-111
Brain and Development

Case report
Hemiconvulsion–hemiplegia–epilepsy syndrome: Early magnetic resonance imaging findings and neuroradiological follow-up

https://doi.org/10.1016/j.braindev.2006.06.005Get rights and content

Abstract

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.

Introduction

HHE syndrome is characterized by prolonged unilateral convulsions during fever in children under 4 years of age, who subsequently develop a transient or definitive hemiplegia. Later partial epilepsy is often observed. An extensive atrophy of the involved hemisphere is also documented by neuroimaging.

Longitudinal MRI studies are rare and the pathogenesis of the abnormalities observed in the early and in the later stages is still poorly understood [1], [2], [3].

We describe a two-year and nine-month-old child with HHE syndrome with a neuroradiological and clinical follow-up of 8 months.

Section snippets

Case report

A two-year and nine-month-old boy was admitted for a prolonged right sided partial motor seizure (45 min) during fever (body temperature 39 °C). Two days after the admission he had two similar though shorter convulsions followed by right hemiparesis. EEG was characterized by slow and low amplitude electrical activity on the left hemisphere. Cranial computed tomography (CT) (third day) showed signs of unilateral cerebral edema. A MRI of 7 days later showed on T2-weighted images a diffuse swelling

Discussion

MRI findings in the few HHE patients reported in the literature seem to be very peculiar. Early stages are characterised by T2 and DWI hyperintensity and reduced ADC involving predominantly the subcortical white matter of the affected hemisphere.

These alterations, that usually disappear in about 1 month [1], [2], [3], correlate with the neuropathological findings reported by some authors [1], [4], [5], including diffuse laminar necrosis and edema in cortical layers 3 and 5, extending throughout

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