Outcome of spontaneous subarachnoid hemorrhage of unknown etiology.

During a 7-year period, 56 patients with a verified subarachnoid hemorrhage (SAH) in whom neuroradiological investigations failed to reveal a reasonable cause of the bleeding were evaluated. Forty-six patients who survived the SAH were interviewed at a follow-up examination from 10 to 82 months (mean 37 months) after the bleeding. Early prognosis of an unfavorable outcome was possible on the basis of two clinical variables: the poor Glasgow coma scale (GCS < = 11) at admission and the Fisher's SAH grade of greater than II on brain computerized tomographic scans. Other clinical variables in the acute stage, including age, sex, a history of hypertension and the complications of SAH, such as vasospasm, hydrocephalus, and rebleeding, were not related to the early outcome. GCS on discharge was predictive of activity of daily life at follow-up review. On the follow-up, 80% of the patients experienced a good recovery. Rebleeding episode occurred in a patient 5 years after the bleeding. The overall rebleeding rate was 2.2% (equivalent to an annual recurrence of 0.7%). This study confirmed a good prognosis for patients with SAH of unknown cause. We recommend that after thorough panangiography, those patients with SAH of unknown etiology should be encouraged to return to a normal life style without any restriction.