Essential knowledge for the management of Lower GI Hemorrhage (LGIB), a common and high-stakes emergency. Initial management requires recognizing if the source is likely upper GI (hematochezia plus instability) and strict transfusion targets (Hgb 7; Hgb 9 for cardiovascular risk patients). Risk stratification hinges on the Shock Index and the Oakland Score, where a score of eight or less predicts safe outpatient discharge. The diagnostic pathway utilizes CTA for low-flow bleeds and angiography for high-flow bleeds. For endoscopic intervention, clips are strictly preferred over thermal energy for diverticular bleeding due to perforation risk. Surgical intervention is the last resort, emphasizing the need for India Ink tattooing to localize the source, allowing for a targeted segmental colectomy rather than a high-morbidity blind subtotal colectomy.
