Outcome in perimesencephalic (nonaneurysmal) subarachnoid hemorrhage: a follow-up study in 37 patients

We interviewed 37 patients with perimesencephalic hemorrhage, 18 months to 7 years after the bleed. None rebled or had persisting neurologic deficits. These findings are remarkably good compared with recent series of patients with subarachnoid hemorrhage and normal angiogram. When blood is confined to the mesencephalic cisterns in patients with normal angiogram, repeat angiography may not be indicated.