A patient presented with thunder clap headache followed by unconsciousness with pregressive III ranial nerve palsy. Likely diagnosis is -

Ans. is 'b' i.e., Aneurysmal subarachnoid hemorrhage Thunderclap headache is an acute and severe headache that is maximum in intensity at onset and has been likened to a clap of thunder.The term TCH was initially used by Day and Raskin in reference to the pain associated with an unruptured intracranial aneurysm,However, multiple causes of Thunderclap headache have since been described."Subarachnoid hemorrhage is the most common cause of thunder- clap headache Q".Primary Thunder Clap headachePrimary TCH is diagnosed when all other potential underlying causes have been eliminated by diagnostic testing.Primary TCH's can recur intermittently and are generally associated with benign outcome.Ischaemic strokeAcute hypertensive crisisReversible cerebral vasoconstriction syndromeThird ventricle colloid cystIntracranial infectionPrimary thunderclap headachePrimary cough, sexual and exertional headache