Lower gastrointestinal bleeding: is urgent colonoscopy necessary for all hematochezia?

Lower gastrointestinal bleeding (LGIB) is defined as acute or chronic abnormal blood loss distal to the ligament of Treitz. The incidence of LGIB is only one fifth of that of the upper gastrointestinal tract and is estimated to be 21 to 27 cases per 100,000 adults per year. Acute bleeding is arbitrarily defined as bleeding of <3 days' duration resulting in instability of vital signs, anemia, and/or need for blood transfusion. Chronic bleeding is defined as slow blood loss over a period of several days or longer presenting with symptoms of occult fecal blood, intermittent melena, or scant hematochezia. Bleeding means that the amounts of blood in the feces are too small to be seen but detectable by chemical tests. LGIB is usually chronic and stops spontaneously. Bleeding stop (80%), but male gender and older patients suffer from more severe LGIB. The optimal timing of colonoscopic intervention for LGIB remains uncertain. Urgent colonoscopy may serve to decrease hospital stay. However, urgent colonoscopy is difficult to control, and showed no evidence of improving clinical outcomes or lowering costs as compared with routine elective colonoscopy.