Benign subarachnoid haemorrhage (subarachnoid haemorrhage of unknown aetiology).

Forty three patients of subarachnoid haemorrhage of unknown aetiology have been studied for their clinical presentation, rebleed rate, morbidity and mortality. The results have been compared with other similar studies. The present study and those of others indicate a very good prognosis in acute stage. The rebleed rate ranged between 0 and 7% over a period of two to three years. The mortality rate ranged between 0 and 5% during the same period of follow-up. Majority of the patients returned to their full working capacity. The benign nature of this subgroup as compared to the poor outcome of subarachnoid haemorrhage as a whole prompted us to call it "Benign subarachnoid haemorrhage".