<prompt> A patient presents with sudden headache and vomiting and unconsciousness. The diagnosis isSubarachnoid hemorrhage -Intracerebral hemorrhageSubdural hemorrhageExtradural hemorrhage  <response>: MC cause: Trauma Spontaneous rupture of Berry aneurysmClinical Features Sudden transient loss of consciousness occurs in nearly half of the patients Excruciating severe headache: presenting complaint in 45 of cases worst headache of patients life more common upon regaining consciousness when loss of consciousness is associated Neck stiffness and vomiting: are common associations Focal neurological deficit: uncommon. Sudden headache in the absence of focal neurological deficit is the hallmark of aneurysmal rupture. Associated prodromal symptoms suggest location of progressively enlarging unruptured aneurysm: Third cranial nerve palsy: Aneurysm at junction of PCA and ICA Sixth nerve palsy: Aneurysm in cavernous sinus Occipital and posterior cervical pain: Inferior cerebellar artery aneurysm Pain in or behind the eye: MCA aneurysmDiagnosis Non contrast CT scan: Investigation of choice Lumbar puncture is not indicated prior to an imaging procedure CSF picture: Hallmark of aneurysmal rupture is blood in CSF Xanthochromic spinal fluid 