<prompt> Most common cause of subarachnoid haemorrhage isAneurysmA-V malformationTraumaHypertension  <response>: C Trauma Most common cause of Subarachnoid haemorrhage is Berry aneurysm. Most common cause of spontaneous subarachnoid haemorrhage is rupture of saccular aneurysm. Autopsy has revealed 3-4 of population harbour aneurysm. According to Harrison ... .Excluding head trauma, the most common cause of SAH is rupture of a saccular aneurysm... Head trauma is not a spontaneous cause of SAH. Sudden severe headache is the commonest presentation of subarachnoid haemorrhage. Mortality rate is about 50 in first month. Arteriovenous malformation presents as stroke in young person. 85 of the aneurysms occur in the anterior circulation of Willis. Prodromal symptoms help to localize unruptured aneurysm. 3rd nerve palsy with loss of light reflex and pain above or behind eye: Aneurysm at junction of posterior communicating internal carotid artery. 6th nerve palsy: Aneurysm at cavernous sinus. Occipital or posterior cervical pain: Aneurysm at posterior inferior cerebellar artery or anterior inferior cerebellar artery. Four major causes of delayed neurological deficit are - rerupture, hydrocephalus, vasospasm and hyponatraemia. Vasospasm is the major cause of delayed neurological deficit.; The incidence of rerupture is maximum at 7th day. The signs of vasospasm are maximum at 7th day. MC cause of CVA - Thrombosis MC site of Hypertensive bleeds Putamen MC site of berry aneurysm-Ant, cerebral- ant, communicating art, junction This one has been repeated so many times. Excluding trauma, the most common cause of subarachnoid hemorrhag e is rupture of aneurysm Causes of subarachnoid hemorrhage: Trauma most common; Rupture of Berrys aneurysm; Rupture of A.V. malformation Causes of subarachnoid haemorrhage: Aneurysms ... 70 Arteriovenous malformations ... 10 Idiopathic... 5 Other: Spinal AVM, Tumour, Coagulopathy 