ABSTRACT
The leading cause of spontaneous subarachnoid hemorrhage (SAH) is rupture of an intracranial aneurysm. Aneurysms most commonly are located at branch points in the circle of Willis at the base of the brain. At the time of hemorrhage, there is extravasation of blood into the subarachnoid spaces covering the central nervous system, which contains cerebrospinal fluid. The severity of clinical presentation is the strongest prognostic indicator in SAH. Initial clinical severity is measured by the Hunt and Hess grading system. Higher scores correlate to poorer outcomes. If a computed tomography (CT) scan reveals an SAH and the CT or cerebral angiogram shows the presence of an aneurysm, a decision is made whether an aneurysm is amenable to coiling or whether to expedite microsurgery to prevent risk of re-bleeding. According to current American Heart Association guidelines, microsurgical clipping may receive increased consideration in patients presenting with large intraparenchymal hematomas and middle cerebral artery aneurysms.
