Colonic bleeding

Lower gastrointestinal (GI) hemorrhage is defined as bleeding that originates distal to the ligament of Treitz and accounts for 20-25% of all cases of acute GI hemorrhage. Bleeding may therefore originate from the small bowel in addition to the colon and anorectum. Acute small bowel bleeding is rare and represents a distinct entity. This chapter concentrates on colonic causes of major lower GI hemorrhage. Bleeding of anorectal origin is a common cause of lower GI hemorrhage and can be difficult to differentiate from colonic pathology. The management of anal canal bleeding is discussed in Chap. 2. In addition to an acute or clinically overt hemorrhage, patients with colonic bleeding can present in an occult and chronic manner to the primary care physician and are subsequently referred to the surgical outpatient department. This chapter reviews the etiology, investigation, and management of colonic bleeding in both the outpatient and emergency setting.