Where do lower GI bleeds typically occur?

Lower gastrointestinal (GI) bleeding refers to bleeding that originates from the lower part of the digestive tract, which includes the jejunum, ileum, colon, and rectum. This categorization is crucial for diagnosing and managing such bleeding. The term "lower GI" specifically denotes that the bleed occurs distal to the ligament of Treitz, which separates the upper GI tract from the lower.

The jejunum and ileum are part of the small intestine but are included in the lower GI bleeding classification when considering the entirety of the gastrointestinal tract, especially since conditions affecting these areas, such as Crohn's disease or angiodysplasia, can lead to significant bleeding. The colon and rectum are major sites for lower GI bleeding and can be affected by a variety of conditions, including diverticulosis, colorectal cancer, and inflammatory bowel disease.

Understanding the anatomy and possible sites of bleeding helps healthcare providers effectively localize the source of the bleed. This knowledge is essential for choosing the appropriate diagnostic and therapeutic interventions, ultimately leading to better patient outcomes.