Most common cause of subarachnoid hemorrhage: September 2011

Ans. B: Rupture of berry aneurysm Eighty-five percent of SAH are caused by saccular or 'berry' aneurysms arising from the bifurcation of cerebral aeries, paicularly in the region of Circle of Willis SAH: Most aneurysm presents as sudden SAH Occipital and posterior cervical pain may signal a posterior inferior cerebellar aery or anterior inferior cerebellar aery aneurysm (rare) A classic presentation of SAH is the explosive onset of sever headache (thunder clap type headache), or a sudden transient loss of consciousness followed by severe headache Nuchal rigidity and vomiting may be present (simulating meningitis) Rebleed and vasospasm are responsible for clinical deterioration in a week following CT scan is a sensitive indicator and usually allows for prompt diagnosis