Massive bleeding per rectum in a 70years patient is seen most commonly in

Hemorrhage from a colonic diveiculum is the most common cause of hematochezia in patients >60 years, yet only 20% of patients with diveiculosis will have gastrointestinal bleeding. Patients at increased risk for bleeding tend to be hypeensive, have atherosclerosis, and regularly use aspirin and nonsteroidal anti-inflammatory agents. Most bleeds are self-limited and stop spontaneously with bowel rest. The lifetime risk of rebleeding is 25%.Reference: Harrison&;s Principles of Internal Medicine; 19th edition; Chapter 353; Diveicular Disease and Common Anorectal Disorder