Methods

Spontaneous subarachnoid hemorrhage (SAH) is usually caused by rupture of an intracranial aneurysm. In up to 15 % of patients with spontaneous SAH, no bleeding source can be identified despite of repetitive radiological imaging [1-5]. In 20 to 70 % of patients with angiography negative SAH the blood distribution is described as perimesence-phalic or prepontine [6]. Patients with perimesencephalic SAH are considered to achieve a good outcome and to have a lower risk of rebleeding [6,7]. However, data on patients suffering from spontaneous non-aneurysmal SAH is lim-ited. There are a few studies reporting on a limited number of patients [2,8-12]. Therefore, the aim of the present study was to investigate the clinical course and outcome in patients suffering from non-aneurysmal spontaneous SAH