[Clinical, neuroradiologic and developmental aspects of idiopathic benign subarachnoid hemorrhage (subarachnoid hemorrhage of unknown cause). Retrospective study of 65 cases].

Sixty-five patients with a mean age of 50.2 +/- 10.9 were admitted with a subarachnoid hemorrhage and a subsequent normal cerebral panangiography. On admission, 69% of the patients were graded I or II on the Hunt and Hess scale, versus 14% of them admitted on grade IV or V. Fifty-one patients (78%) were submitted to a second angiography between day 10 and day 132 after their hemorrhage (average day 29). A third angiography was performed on twenty-six patients (40%). Angiographic vasospasm was present on 52% of the first angiograms and affected predominantly the vertebro-basilar arterial system. On the second angiography, the vasospasm was still present on 26 out of 32 angiograms performed before day 30, and was only noted on 2 out of 19 angiograms performed later. No rebleeding was recorded in this group of patients who were followed-up for an average of 49 +/- 23 months. Complication as acute hydrocephalus affected 17% of the patients. In two patients (3%), symptomatic vasospasm was judged responsible of a delayed neurological deficit with concomitant hypodensity on the CT scan. Angiographic explorations were complicated by a transient ischemic deficit in 3 cases and by a fatal stroke in one case (4 cases out of 65 procedures, or 6%). As another patient died with bronchopneumonia during the hospitalization, the initial mortality rate was 3%. During the period of follow-up, two patients died from medical causes unrelated to their initial hemorrhage. Finally, 92% of the patients were alive and in an excellent or good clinical condition.(ABSTRACT TRUNCATED AT 250 WORDS)