GI Bleeding Basics

A gastrointestinal bleed is blood loss into the digestive tract. The first clinical question is not simply “Where is the blood?” but “Has enough blood been lost to impair perfusion?” Upper GI bleeding (UGIB) originates proximal to the ligament of Treitz. Common causes include peptic ulcer disease, a Mallory-Weiss tear after forceful retching, oesophageal or gastric varices, and vascular lesions. Lower GI bleeding (LGIB) originates distal to the ligament of Treitz and may result from diverticular bleeding, vascular lesions, colitis, or anorectal disease. The appearance of the blood provides a useful starting point: - Haematemesis is vomiting bright-red blood or dark, granular “coffee-ground” material. Coffee-ground emesis means blood has remained in the stomach long enough for acid to alter haemoglobin; it still represents a potentially serious bleed. - Melena is black, sticky, often foul-smelling stool caused by digestion of blood during intestinal transit. It usually suggests UGIB, although slow bleeding from more distal bowel can occasionally darken the stool. - Hematochezia is passage of bright-red or maroon blood per rectum. It commonly suggests LGIB, but a brisk UGIB can move...