Cerebral vasospasm is the sudden acute narrowing of cerebral blood vessels that can occur 3–4 days after the onset of a subarachnoid hemorrhage (SAH) stroke resulting from a rupture of a cerebral aneurysm.
By causing reduced cerebral blood flow to the affected area, it causes cerebral ischemia, and consequently vasospasm is a significant cause of morbidity and mortality following SAH. Arterial vasospasm is seen in 40–70% of SAH patients on cerebral angiogram, but symptoms occur in about 20–30%. It can cause confusion, reduced consciousness, and ultimately coma and death. When it is less severe, neurological recovery occurs as the arterial narrowing resolves. Treatment involves administration of selected medications and fluids to reduce the vasospasm.