This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'Massive bleeding per rectum in a 70 yr old patient is due to ? \nSelect and explain. \nA. Diveiculosis, B. Carcinoma colon, C. Colitis, D. Polyps', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Diveiculosis Causes of lower GI bleed in adults 1) Local anorectal diseases - hemorrhoids (most common), anal fisures.2) Diveiculosis (2nd MC)3) Vascular ectasias, angiodysplasias4) Neoplasm (polyps & adenocarcinoma)5) Colitis (Ischemic, infectious, & IBD)Although hemorrhoids are the MC cause of bleeding per rectum, it causes small bleed.Diveiculosis is the MC cause of massive bleeding per rectum.Diveicular bleeding is abrupt in onset usually painless, sometimes massive, and often from the right colon. The bleeding stops spontaneously in approx. 80% of patients and rebleeds in 20-25% of pts.", 'role': 'assistant'}]