Upper GI Bleeding
Diverticular disease
Diverticulosis
Diverticulitis
Vascular ectasia / angiodysplasia
Inflammatory bowel disease
Infectious colitis
Mesenteric Ischemia / ischemic colitis<unk> 
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
Diverticulosis
Diverticulitis
Internal hemorrhoid
External hemorrhoid
Nearly 100% mortality if untreated
Consider in patients with gastrointestinal bleeding and known abdominal aortic aneurysms or aortic grafts
Meckel's diverticulum
Upper GI Bleeding
Intussusception
Diverticular disease
Hirschsprung's disease
Diverticulosis
Zenker's diverticulum
Diverticulitis