Gac Med Mex
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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. ⋯ 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.