[Reversible cerebral vasoconstriction syndrome: A rare pediatric cause of thunderclap headaches]. / Syndrome de vasoconstriction cérébrale réversible : une cause de céphalée en coup de tonnerre peu connue chez l'enfant.

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by thunderclap headaches with diffuse segmental constriction of cerebral arteries that resolves spontaneously within 3 months. We report on a case of a 13-year-old boy presenting with acute severe headaches, triggered by physical exertion. His past medical history was uneventful. Moderate headache persisted between exacerbations for 4 weeks. He secondarily presented with signs of intracranial hypertension. Brain magnetic resonance angiography (MRA) revealed multifocal narrowing of the cerebral arteries. A glucocorticoid treatment was started based on the hypothesis of primary angiitis of the CNS. The symptoms rapidly improved, and repeat angiography at 3 months showed no vasoconstriction. Although pediatric cases are rare, RCVS should be considered in a child complaining of severe headache, especially after the use of vasoactive drugs or after Valsalva manoeuvres. RCVS is attributed to a transient, reversible dysregulation of cerebral vascular tone, which leads to multifocal arterial constriction and dilation. Physical examination, laboratory values, and initial cranial computed tomography are unremarkable, except when RCVS is associated with complications. Thunderclap headaches tend to resolve and then recur over a 1- to 4-week period, often with a milder baseline headache persisting between acute exacerbations. Angiography shows segmental narrowing and dilatation of one or more arteries, like a string of beads. Despite the absence of a proven treatment, important steps should be taken during the acute phase: removal of precipitants such as vasoactive substances, giving the patient rest, lowering blood pressure, and controlling seizures. Drugs targeted at vasospasms, such as calcium channel inhibitors, can be considered when cerebral vasoconstriction has been assessed. In most patients, the RCVS symptoms resolve spontaneously within days or weeks. Ischemic and hemorrhagic stroke are the major complications of the syndrome. A diagnosis of RCVS can only be confirmed when the reversibility of the vasoconstriction is assessed.