<prompt> Most Common cause of subarachnoid hemorrhage is: March 2009Rupture of bridging veinsSaccular aneurysm ruptureHypeensionIdiopathic  <response>: Ans. B: Saccular aneurysm rupture Excluding head trauma, the most common cause of subarachnoid hemorrhage SAH is hemorrhage from an intracranial aneurysm. Other causes include vascular malformations, tumors, and infection. The management of aneurysmal SAH has changed due to superiority of early surgery for clipping of ruptured aneurysms. This superiority derives from the relative safety of early aneurysm surgery and the major threat of early rebleeding approximately 25 in three weeks after SAH. 