Cerebral artery spasm: histological changes in necropsies of cases of subarachnoid hemorrhage.

A group of 20 necropsies of subarachnoid hemorrhage (SAH) were selected because of the known complication of cerebral vasospasm. Evidence for vasospasm was radiological and pathological in 17 cases and pathological alone in 3 cases. A histological examination of the large arteries in areas known formerly to be in spasm showed that in the 13 early cases (death before 3 weeks) there were relevant changes in all layers of the arterial wall, the most significant being a degeneration of the media and elastica. In the 7 late cases (death after 3 weeks), in addition to the sequelae of the acute changes, there was marked concentric intimal thickening; and the localization was again in the particular segments of arteries formerly in spasm. Changes found in the small arteries, capillaries, and veins in the early and the late cases were thought to be caused by the ischemia due to the vasospasm. These changes were also seen in control material.