INTRODUCTION
Lower gastrointestinal (GI) bleeding is a frequent cause for hospital admissions with an annual incidence of approximately 20 to 27 cases per 100,000 persons in the United States.1 Morbidity and mortality vary according to the underlying cause of the GI bleed, with reported mortality rates of 2% to 20% for lower GI bleeding and as high as 40% for hemodynamically unstable patients.2 Lower GI bleeding is defined as bleeding that occurs distal to the ligament of Treitz, with upper GI bleeding occurring proximally. Clinical presentations vary based on the source of the bleed and cause; however, acute lower GI bleeds typically present with hematochezia, noting that secondary to the cathartic effects of blood, a brisk upper GI bleed may present in a similar manner.3 Causes of lower GI bleeding may be anatomic, such as diverticulosis (33.5%); vascular, such as hemorrhoids (22.5%), angioectasia, or ischemia; neoplastic (12.7%); inflammatory as with inflammatory bowel disease; or infectious.4 If the workup of the large bowel is negative, then patients are suspected of having a small bowel bleed. There are several classification schemes used to describe lower GI bleeding related to the duration and severity of the bleed as well as the results of upper and lower endoscopy/imaging. When correlating with the amount of bleeding, lower GI bleeds can be categorized as massive, moderate, or occult. Massive bleeding is defined by the passage of profuse hematochezia with hemodynamic instability. Moderate bleeding reflects hematochezia in hemodynamically stable patients.
