Article

Hemiconvulsion-hemiplegia syndrome (HHS) is a rare severe epilepsy of
infancy consisting of unilateral convulsive status epilepticus immediately
followed by transient or lasting ipsilateral hemiplegia. HHS may occur either in
patients with previous brain pathology or without any identified cause, so-called
'idiopathic HHS'. METHOD: We retrospectively analysed clinical and MRI
longitudinal findings of a series of 10 patients (six females, four males)
presenting with HHS. Age at the study inclusion ranged from 2 years 6 months to
15 years (mean of 5 y 10 mo, median 4 y 2 mo). After defining magnetic resonance
imaging (MRI) features as 'typical', i.e. strictly unilateral involvement, and
'atypical', i.e. bilateral, we compared clinical data from both groups. Cognitive
level was assessed using Brunet-Lezine or Wechsler scales. RESULTS: HHS occurred
at a mean age of 20.5 months (range 8-48 mo). In all cases, status epilepticus
lasted for more than 1 hour and was characterised by unilateral clonic seizures
followed by ipsilateral hemiplegia (persistent in five patients). Two patients in
this series died: the first from multi-organ failure 2 weeks after the status
epilepticus and the other from a second episode of ipsilateral intractable
febrile status epilepticus 3 years after the first episode. Early MRI (days 1-7
from status epilepticus) showed hemispheric cytotoxic oedema in all, extending to
the contralateral side for one. T2 hyperintensity in the basal ganglia was
disclosed in 70% of patients and in the hippocampus in 60%. After 1 month (in
intermediate and chronic phases), all surviving patients but one showed
hemispheric cortical atrophy corresponding to the regions involved during the
early stage. Comparing clinical features of patients presenting with 'typical'
features, to those with 'atypical' findings, the second group presented
psychomotor delay before status epilepticus. This series
underlines the major value of early MRI for the prompt diagnosis of HHS, and
shows that involvement of subcortical structures has been underestimated.
Hippocampal involvement is not constant.
CI - (c) 2013 Mac Keith Press.

Langue : ANGLAIS