[Subarachnoid hemorrhage with negative angiography]

Subarachnoid hemorrhage constitutes approximately 10% of cases of cerebrovascular disease and its incidence ranges between 11 and 28 cases/100,000/year. More than 80% of cases are secondary to rupture of cerebral aneurysm; however, in 5 to 16% of patients with subarachnoid hemorrhage it is not possible to find a cause (subarachnoid hemorrhage with negative angiography). This group of patients represents a dilemma for the correct diagnosis, treatment and prognosis; there is no consensus on the criteria to repeat the angiography after the first negative study. The results of our study includes 14 patients with subarachnoid hemorrhage and negative angiography. The angiographic study was repeated two or more times. Our observations suggest that the overall prognosis for these patients is very good (86%). The risk of another hemorrhage after discharge from the hospital is small. Our results are compared with those in other published series.