**7.9 Calcium channel blockers for reversible cerebral vasoconstriction syndrome**

Reversible cerebral vasoconstriction syndrome (RCVS) represents a group of conditions that show a reversible narrowing of the cerebral arteries with clinical manifestations that typically include thunderclap headache and less commonly neurologic deficits related to brain edema, seizure, or stroke. The clinical outcome is usually benign, although major strokes can result in severe disability and death in a minority. The pathophysiology of the abrupt-onset headache and the prolonged but reversible vasoconstriction is not known. Reversible angiographic narrowing suggests an abnormality in the control of cerebrovascular tone [24].

RCVS has been associated with a variety of conditions including pregnancy, migraine, use of vasoconstrictive drugs, neurosurgical procedures, hypercalcemia, unruptured saccular aneurysms, cervical artery dissection, and cerebral venous thrombosis. The diagnosis of RCVS is based upon the characteristic clinical, brain imaging, and angiographic features. Nimodipine and verapamil and brief courses of magnesium sulfate, serotonin antagonists, and dantrolene have been administered to relieve the vasoconstriction. Data from two prospective case series suggest that nimodipine does not affect the time course of cerebral vasoconstriction [25, 26]. However, nimodipine might relieve the number and intensity of headaches and has documented effects on the smaller vasculature not easily imaged by angiography. Calcium channel blockers can be discontinued after resolution of symptoms or angiographic abnormalities if they are used.
