Patterns of stroke. An analysis of the first 700 consecutive admissions to the Austin Hospital Stroke Unit.

An analysis is presented of the first 700 admissions to the Austin Hospital Stroke Unit with special emphasis on the incidence of the various patterns of stroke and the underlying mechanisms involved. There were 616 admissions for confirmed stroke events--the remainder were for events simulating stroke. Three hundred and fifty-three (57.3% of stroke events) were for cortical (including retinal) ischaemic events. Of these, arterial lesions were demonstrated in 55% and suspected in 20% whilst embolism from the heart probably accounted for 14% of events. No cause was determined in 11% despite complete investigation. Where arterial lesions were found, they were extracranial in 85%. There were 140 cases of internal capsular ischaemia (22.7% of stroke events) and 16 cases (2.6%) for which the exact site of ischaemia was not determined, although it was presumed to have occurred within the carotid territory. Vertebrobasilar ischaemic events were responsible for 71 admissions (11.5%). There were 36 cases of primary intracerebral haemorrhage (5.8%). This survey has highlighted some aspects of stroke requiring further research. These include the elucidation of cortical and retinal ischaemic events of unknown aetiology, the possible role of large vessel lesions in the pathogenesis of capsular ischaemic events and pathologic mechanisms involved in ischaemic events of the vertebrobasilar territory.