[Reversible cerebral vasoconstriction syndrome - a common cause of thunderclap headache]

Reversible cerebral vasoconstriction is characterized by thunderclap headache and vasoconstriction of cerebral arteries, with or without focal neurologic symptoms. The syndrome is three times more common in women with a mean age around 45 years. In approximately 60% of cases a cause can be identified, commonly after intake of vasoactive substances. The pathophysiology of reversible cerebral vasoconstriction syndrome is unknown, though temporary dysregulation in cerebral vascular tone is thought to be a key underlying mechanism. The syndrome typically follows a benign course; however, complications such as ischemic stroke or intracranial hemorrhage can cause permanent disability or death in a small minority of patients. Vascular imaging reveals alternating cerebral vasoconstriction and vasodilation that normalizes within 12 weeks. Calcium channel antagonists such as nimodipine reduce the frequency of thunderclap headaches but do not decidedly affect the risk of cerebral ischemia or hemorrhage. In this article the epidemiology, risk factors, pathophysiology, symptoms, diagnosis and treatment of RCVS is reviewed.