Definition
Lower gastrointestinal bleeding is bleeding from the rectum which starts distal to the ligament of treitz, a fold of peritoneum which holds up the duodenojejunal flexure.3
It comprises:
- Haematochezia: bright red blood passed rectally
- Malaena: black, tarry stool, suggesting altered blood which has been partially digested after a prolonged period passing through the GI tract.