Thunderclap headache and reversible cerebral vasoconstriction syndrome: Current theory and accumulated data

Abstract

Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by recurrent severe thunderclap headache and segmental vasoconstriction of cerebral arteries that resolves by 3 months. RCVS can either occur spontaneously or relate to an exogenous trigger, but the precise pathophysiology of RCVS remains unknown.Postulated mechanisms include small vessel and endothelial dysfunction, mitochondrial dysfunction with oxidative stress, hormonal and biochemical factors, and genetic predisposition. A prior history of migraine has been reported in 17%-40% of cases, suggesting that migraine and RCVS share mechanisms. Most RCVS patients have a favorable prognosis; however, for some patients, the condition may result in permanent disability or even death in a small minority of patients, secondary to complications such as ischemic stroke or intracranial hemorrhage. There is no proven treatment, so the cornerstone of RCVS management remains largely supportive, with prescription of bed rest, analgesics, and the removal of precipitating factors. The majority of clinical series studying RCVS treatment have investigated the efficacy of calcium channel antagonists. Although prescription of triptans for migraine is not suitable for patients with a history of RCVS, lasmiditan, a highly selective 5-HT 1F receptor agonist, may be suitable in such cases. Typical segmental vasoconstriction of major vessels is not seen in approximately 30% of patients eventually diagnosed with RCVS; if this diagnosis is suspected, repeat imaging should be performed. Early diagnosis of RCVS is important, as it allows progression to be prevented by the prompt removal of precipitating factors, unnecessary diagnostic procedures to be avoided, and appropriate management to be commenced.