Accidents vasculaires cérébraux de la fosse postérieure chez l’enfant : à propos de trois cas

RésuméLes accidents vasculaires cérébraux (AVC) chez l’enfant sont rares. Il s’agit le plus souvent d’AVC ischémiques sus-tentoriels alors que les AVC ischémiques survenant dans la fosse postérieure chez l’enfant sont peu décrits. Les signes cliniques peuvent être évocateurs (ataxie, paralysie des nerfs crâniens) mais sont souvent peu spécifiques (troubles de la conscience, déficits sensitivomoteurs), posant un problème de diagnostic différentiel et donc de retard dans la prise en charge thérapeutique. Le plus souvent, aucune cause n’est trouvée. À partir de 3 observations d’AVC ischémiques de la fosse postérieure chez l’enfant, sont discutés les aspects cliniques et radiologiques.

SummaryIschemic stroke is rare in children, most of which occur in the supratentorial brain, and infratentorial infarcts are very rare. Some clinical manifestations may be similar but others such as ataxia and cranial nerve palsy are more specific. Vertebral artery dissection is the most frequent cause of stroke in the vertebrobasilar territory, but the cause most often remains unknown in children. We report three cases of infratentorial stroke in children. The first observation concerns a 4-year-old boy brought to medical attention because left hemicorporal motor deficit associated with ataxia following a minor cranial traumatism. While computed tomography (CT) of the brain was normal, magnetic resonance imaging (MRI) revealed an area of signal alteration on the diffusion-weighted image within the right protuberance. The second observation is a 15-year-old girl who developed sudden-onset ataxia. The CT scan and MRI of the brain revealed an acute bilateral cerebellar stroke. MRI angiography showed an anatomical variant of the left vertebral artery that did not participate in the Willis polygon. In these two observations, no other abnormalities were detected except they were homozygotous for MTHFR mutation in the first observation and minor alpha-thalassemia for the second one. The outcome in these two children was good without sequelae after a 6-month follow-up. The third observation is a 6-year-old girl who suddenly exhibited cephalalgia, ataxia, and left visual impairment. The brain MRI revealed left occipital and cerebellar strokes due to vertebral artery dissection. The authors recommend the systematic search for vertebral artery dissection in cases of infratentorial stroke.