The following are possible causes of a<unk> : * Diverticular disease — diverticulosis, diverticulitis * Colitis * Ischaemic colitis * Radiation colitis * Infectious colitis * Pseudomembranous colitis * E. coli O157:H7 * Shigella * Salmonella * Campylobacter jejuni * Hemorrhoids * Neoplasm — such as colorectal cancer * Angiodysplasia * Bleeding from a site where a colonic polyp was removed * Inflammatory bowel disease such as Crohn's disease or ulcerative colitis * Rectal varices * Coagulopathy — specifically a bleeding diathesis * Anal fissures * Rectal foreign bodies * Mesenteric ischemia * NSAIDs * Entamoeba histolytica * Stercoral ulceration * Dieulafoy lesion (rare)
Lower gastrointestinal bleeding
Upper gastrointestinal bleeding
Internal bleeding
Rectal bleeding
Gastric varices
Gastrointestinal bleeding
Retroperitoneal bleeding
Nosebleed