Nontraumatic subarachnoid hemorrhage is a neurosurgical emergency characterized by the extravasation of blood into the spaces covering the central nervous system that are filled with cerebrospinal fluid. The leading cause of nontraumatic subarachnoid hemorrhage is rupture of an intracranial aneurysm, which accounts for about 80 percent of cases and has a high rate of death and complications. The management of aneurysmal SAH has changed significantly over the past few years. This change is mostly due to the demonstration of the superiority of early diagnosis, surgical clipping or endovascular embolization of ruptured aneurysms. This superiority derives from the relative safety of early aneurysm occlusion and the major threat of early rebleeding (approximately 25% in three weeks after SAH).