Causes of Massive Lower Gastrointestinal Bleeding

Common Etiologies

• The American College of Radiology suggests that diverticulosis is the most frequent cause of massive lower gastrointestinal bleeding, accounting for approximately 30% of cases 1
• Approximately 75% of episodes of acute lower GIB due to diverticulosis stop spontaneously, as reported by the American College of Radiology 1
• Empirical embolization for tumor bleeding has shown clinical success rates of 68%, increasing to 98% in the context of acute bleeding, according to the Gut journal 2
• Massive, life-threatening LGIB is uncommon in IBD patients, occurring in less than 6% of cases, as stated by the World Journal of Emergency Surgery 3
• In ulcerative colitis, bleeding typically occurs in patients with pancolitis from diffuse areas of mucosal ulceration, according to the World Journal of Emergency Surgery 3
• The World Journal of Emergency Surgery recommends that patients with massive LGIB receive intravenous fluid/blood product resuscitation with the goal of normalizing blood pressure and heart rate prior to endoscopic evaluation/intervention 3
• Packed red blood cells should be transfused to maintain hemoglobin above 7g/dL, with a threshold of 9g/dL in patients with massive bleeding, significant comorbidities, or possible delay in therapeutic interventions, as suggested by the World Journal of Emergency Surgery 3
• Restrictive RBC transfusion thresholds (Hb trigger 70 g/L and target 70-90 g/L) should be used in clinically stable patients, unless they have cardiovascular disease (trigger 80 g/L, target 100 g/L), according to the Gut journal 2, 7
• No patient should proceed to emergency laparotomy unless every effort has been made to localize bleeding by radiological and/or endoscopic modalities, as recommended by the Gut journal 2

Diagnostic Approach

• For hemodynamically unstable patients, CT angiography (CTA) should be the first-line investigation to rapidly localize the bleeding site, as suggested by Praxis Medical Insights 5
• CTA is preferred over colonoscopy in unstable patients as it requires no bowel preparation and can identify bleeding sources in the upper GI tract or small bowel, according to Praxis Medical Insights 5
• Approximately 10-15% of apparent LGIB may have an upper GI source, so upper GI endoscopy should be considered if CTA is negative, as recommended by Praxis Medical Insights 5