Nontraumatic subarachnoid hemorrhage from intracranial aneurysm rupture presents with sudden severe headache. Initial treatment focuses on airway management, blood pressure control, and extraventricular drain for hydrocephalus. After identifying the aneurysm, they may be clipped surgically or endovascularly coiled. Nimodipine is administered to maintain a euvolemic state and prevent delayed cerebral ischemia (DCI). Patients may receive anticonvulsants. Monitoring includes serial neurologic assessments, transcranial Doppler ultrasonography, computed tomography perfusion, and angiographic studies. Treatment includes augmentation of blood pressure and cardiac output, cerebral angioplasty, and intra-arterial infusions of vasodilators. Although early mortality is high, about one half of survivors recover with little disability.