Some aspects of the natural history of subarachnoid haemorrhage.

In a population-based stroke incidence study, 27 cases of subarachnoid haemorrhage were identified, an incidence rate of 26.4/10(5) person years at risk. Subarachnoid haemorrhage comprises but a small part of the burden of cerebrovascular disease, but all appear to be admitted to general hospitals. The overall survival rate was 44% to six months, in those cases treated surgically the survival rate was 63%. Of more importance, by six months only 19% were free of residual handicap; in terms of this endpoint, those cases treated surgically were at no advantage as compared with those treated conservatively.