Upper GI Bleeding
Diverticular disease<unk> 
Diverticulitis
Vascular ectasia / angiodysplasia
Inflammatory bowel disease
Infectious colitis
Mesenteric Ischemia / ischemic colitis
Meckel's diverticulum
Colorectal cancer / polyps
Hemorrhoids
Internal hemorrhoid
External hemorrhoid
Aortoenteric fistula
Nearly 100% mortality if untreated
Consider in patients with gastrointestinal bleeding and known abdominal aortic aneurysms or aortic grafts
Rectal foreign body
Rectal ulcer (HIV, Syphilis, STI)
Anal fissure<unk> 
Diverticulitis
Internal hemorrhoid
External hemorrhoid
Nearly 100% mortality if untreated
Consider in patients with gastrointestinal bleeding and known abdominal aortic aneurysms or aortic grafts
Diverticulosis
Upper GI Bleeding
Ischemic colitis
Diverticular disease
Ulcerative colitis
Stercoral colitis
Diverticulitis
Anal fistula