Cerebral microthrombosis in symptomatic cerebral vasospasm--a quantitative histological study in autopsy cases.

A comparative investigation of the pathogenetic factor in symptomatic cerebral vasospasm was made by quantitative histological and clinical studies in four patients who died immediately of symptomatic cerebral vasospasm (Cases 1-4) and in two who died without fatal cerebral vasospasm (Cases 5 and 6). Histological examination of the brain from Cases 1 and 2 found many white and fibrin microthrombi together with ischemic and infarctic changes in the territories of spastic arteries, which corresponded to the low-density areas (LDAs) observed on computed tomographic (CT) scans and the typical neurological symptoms. In Case 3, who had suffered severe vasospasms in bilateral anterior cerebral and middle cerebral arteries, bilateral LDAs were observed on CT scans and multiple fibrin thrombi were seen diffusely throughout the brain. In Case 4, extensive bilateral LDAs (lt greater than rt) were observed on CT scans, and multiple microthrombi were seen diffusely but predominantly in the left cerebral hemisphere. Only in Case 3 the possible complication of disseminated intravascular coagulation could not be ruled out. Only negligible thrombi were observed in Cases 5 and 6, whose immediate cause of death was considered to be acute hydrocephalus and aneurysmal rerupture, respectively. Distributions of microthrombi were significantly greater in the regions clinically identified to have been ischemic or infarctic.