Gastrointestinal Bleeding

Gastrointestinal bleeding can fall into two broad categories: upper and lower sources of bleeding. The anatomic landmark that separates upper and lower bleeds is the ligament of Treitz, also known as the suspensory ligament of the duodenum. This peritoneal structure suspends the duodenojejunal flexure from the retroperitoneum. Bleeding that originates above the ligament of Treitz usually presents either as hematemesis or melena whereas bleeding that originates below most commonly presents as hematochezia. Hematemesis is the regurgitation of blood or blood mixed with stomach contents. Melena is dark, black, and tarry feces that typically has a strong characteristic odor caused by the digestive enzyme activity and intestinal bacteria on hemoglobin. Hematochezia is the passing of bright red blood via the rectum.