<prompt> A patient presented with thunder clap headache. Followed by unconsciousness with progressive 3rd cranial nerve palsyExtradual hemorrhageAneurysmal subarachnoid hemorrhageBasilar migraineCluster Headache  <response>: Harrisons textbook of internal medicine 17th edition . Sudden transient loss of consciousness may be preceded by brief moment of excruciating head ache ,but most patient first complain of head ache on regain the consciousness . 3rd cranial nerve palsy , associate with pupillary dilatation,loss of ipsilateral light reflex,focal pain above and behind the eye . Ref Harrison20th edition pg 2445 