Most common cause of subarachnoid hemorrhage is-

Ans-CNote-Most common cause - trauma most common nontraumatic - a Berry aneurysm* Most common cause of S AH is rupture of a secular aneurysm (excluding head trauma) - Harrison (a Saccular aneurysm are synonymous with Berry aneurysms and most commonly occurs in the anterior circulation on the circle of Willis)* Between 5% and 10% of strokes are due to SAH. Although hemorrhage is usually from rupture of an aneurysm or AV malformation (893-CMDT-10)* A saccular aneurysm (a berry aneurysm) are usually asymptomatic. They may be associated with polycystic kidney disease and co-arctation of the aorta* *** The hallmark of aneurismal rupture is blood in the CSF*** Sudden headache in the absence of focal neurologic symptoms is the hallmark of aneurismal rupture, focal deficits may occur (hemiparesis, aphasia, and abulia)* A mycotic aneurysm is an infected aneurysm resulting from either an extravascular or intravascular source of infection* Resulting from direct trauma to a vessels with secondary infections most commonly occurs in femoral arteries and less commonly in the arteries of neck* The putamen (Basal ganglia) is the most common site hypertensive haemorrhage*** Phenylpropanolamine (PPA) has been associated with hemorrhagic stroke use for weight loss**Resmussen's aneurysm is the dilation of small and medium-sized pulmonary artery** in a tuberculous cavity* The aneurysm involved in massive bleeding in cavitory tuberculous lesion is Bronchial artery* Most common site of peripheral aneurysms is - Popliteal artery** (923- Baily & Love 25th)* Nerve compressed by aneurysm of posterior communicating artery is - Occulomotor nerve*** Pseudoaneurysm in IV drug abusers is commonly found in Femoral, Brachial and radial artery* The best method to monitor intracranial pressure is - Intraventricular catheter*** Most common location of intracranial neurocysticercosis is Brain parenchyma (epileptic seizure is most common symptoms)Diagnostic strategy in SAHInvestigation of choiceMost sensitive investigation to determine etiology||Non contrast CT scan*DSA* of four vessels (both carotid & both vertebral) to define the anatomical details of aneurysm & to determine other unruptured aneurysm exists|If scan fails|Lumber puncture done to establish blood in CSF(Hallmark)* Most common site of rupture of Abdominal aortic aneurysm is - Laterally into the left retroperitoneum*** Subdural hemorrhage - results from tearing of the superior cerebral veins** at their point of entry into the superior sagittal sinus, caused by, blow on the front or back of the head* Cerebral hemorrhage- caused by rupture of the thin-walled lenticulostriate artery a branch of the middle cerebral artery