Colonoscopy in Acute Lower Gastrointestinal Bleeding: Diagnosis, Timing, and Bowel Preparation.

Lower gastrointestinal bleeding is bleeding from a colonic source. Rapid colon purge using 4 to 6 L of polyethylene glycol followed by early colonoscopy, within 24 hours of presentation, is recommended to optimize the detection and management of bleeding sources. Although the data are mixed, early colonoscopy seems to be associated with higher detection of bleeding lesions and therapeutic interventions. There is no clear benefit for early colonoscopy in terms of reduced duration of stay, rebleeding, transfusion requirement, or surgery compared with patients undergoing elective colonoscopy. Further studies are needed to determine the effect of early colonoscopy on clinically important outcomes.