Lower Gastrointestinal Bleeding

Of patients who present with major gastrointestinal (GI) bleeding, 20 to 30% will ultimately be diagnosed with bleeding originating from a lower GI source. Lower GI bleeding has traditionally been defined as bleeding originating from a source distal to the ligament of Treitz; however, with the advent of capsule endoscopy and deep enteroscopy allowing for visualization of the entire small bowel, the definition has been updated to GI bleeding originating from a source distal to the ileocecal valve. Lower GI bleeding can range from occult blood loss to massive bleeding with hemodynamic instability and predominantly affects older individuals, with a mean age at presentation of 63 to 77 years. Comorbid illness, which is a risk factor for mortality from GI bleeding, is also more common with increasing age. Most deaths related to GI bleeding are not due to uncontrolled hemorrhage but exacerbation of underlying comorbidities or nosocomial complications. This review covers the following areas: evaluation of lower GI bleeding (including physical examination and diagnostic tests), initial management, and differential diagnosis. Disorders addressed in the differential diagnosis include diverti