[Acute lower gastrointestinal hemorrhage. Diagnosis and management].

In most cases (80%), acute lower gastrointestinal bleeding stops spontaneously, but rebleeding is frequent (25%). The intensity and quality of the bleeding--hematochezia, melena, or occult bleeding--determines the diagnostic and therapeutic strategy (endoscopic evaluation of the upper and lower gastrointestinal tract, mesenteric angiography, scintigraphy, enteroscopy, capsule endoscopy) and its urgency. Acute lower gastrointestinal bleeding can mostly be treated conservatively or by endoscopic interventions (injection therapy, clip application, coagulation and ligation methods). Severe hemorrhage can render colonoscopy and the identification of the bleeding source technically difficult. Emergency operations are only indicated when patients with severe hemorrhage cannot be stabilized by interventional endoscopy or angiography with selective embolization.