This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pathology
Berry aneurysm most commonly occurs due to? 
Select and explain. 
A. Endothelial injury of vessel due to HTN, B. Muscle intimal elastic lamina layer defect, C. Muscle and adventitial layer defect, D. Adventitia defect
B: Muscle intimal elastic lamina layer defect
Answer: B: Muscle intimal elastic lamina layer defect 
Explanation: Berry aneurysm is due to defect in tunica media and intimal elastic lamina layer leading to weakening of vessel wall and outpouching in anterior poion of circle of willis. Saccular Aneurysms: is a 2nd most common cause of clinically significant subarachnoid hemorrhage is rupture of a saccular ("berry") aneurysm in a cerebral aery following trauma. Patient will describe the pain as worst headache of his life. Bloody tap on lumbar puncture is seen. Nimodipine is a cerebro-selective vasodilatory drug helpful for treatment of symptoms associated with subarachnoid hemorrhage. Berry aneurysm is associated with adult polycystic kidney disease (ADPKD).