title: Lower gastrointestinal bleeding.
abstract: Lower gastrointestinal bleeding is defined as blood loss that originates from a source distal to the ligament of Treitz and results in hemodynamic instability or symptomatic anemia. Although approximately 10% to 15% of patients presenting with acute severe hematochezia have an upper gastrointestinal source of bleeding identified on upper endoscopy, the most common causes of lower gastrointestinal bleeding are diverticulosis, hemorrhoids, ischemic colitis, and angiodysplasia. As with upper gastrointestinal bleeding, lower gastrointestinal bleeding ceases spontaneously in most cases.
authors.affiliation: Department of Medicine, Harvard Medical School, Gastrointestinal Unit, Massachusetts General Hospital, 55 Fruit Street, Blake 453C, Boston, MA 02114, USA. bbounds@partners.org
authors.forename: Brenna Casey
authors.initials: BC
authors.lastname: Bounds
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Friedman
mesh_terms: D000465:Algorithms; D006471:Gastrointestinal Hemorrhage / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D006801:Humans