What is the initial management for a 60-year-old female with massive ongoing lower gastrointestinal hemorrhage presenting with maroon stool, pallor, tachycardia, hemodynamic compromise despite resuscitation, and a soft, non‑tender abdomen?

Initial Management: CT Angiography

For this 60-year-old female with massive ongoing lower gastrointestinal hemorrhage and hemodynamic instability (shock index >1 based on tachycardia), CT angiography (CTA) should be performed immediately as the first diagnostic test—not nasogastric tube, colonoscopy, or barium enema. 1, 2

Why CTA is the Correct Answer

• CTA provides the fastest and least invasive means to localize bleeding in hemodynamically unstable patients, with a sensitivity of 94% and the ability to detect bleeding rates as low as 0.3 mL/min. 1, 2

• CTA is explicitly preferred over colonoscopy in unstable patients (shock index >1) because it requires no bowel preparation, can identify upper GI or small bowel sources, and is widely available. 1, 2

• The British Society of Gastroenterology explicitly recommends against colonoscopy as the initial approach when patients have shock index >1 or remain unstable after resuscitation, reserving it only for stable patients. 2

Why the Other Options Are Wrong

A. Nasogastric Tube (NGT)

• NGT placement is NOT routinely recommended in suspected lower GI bleeding; it does not reliably aid diagnosis, does not affect outcomes, and is complicated in up to one-third of patients. 1

• NGT is appropriate only when an upper GI source is suspected, but maroon-colored stool strongly suggests a lower GI origin, making NGT unnecessary in this case. 2

• Even when used, NGT results are misleading—clear fluid without bile does not reliably exclude upper GI bleeding. 2

C. Colonoscopy

• Colonoscopy is contraindicated in hemodynamically unstable patients because it requires adequate bowel preparation (4-6 L polyethylene glycol over 3-4 hours), which is not feasible in unstable patients. 2

• Urgent colonoscopy does not improve rebleeding, mortality, or length of stay compared to elective colonoscopy after stabilization. 2

• Colonoscopy should be reserved for stable patients or after successful localization and stabilization via angiography. 2

D. Barium Enema

• Barium enema has no role in acute massive lower GI bleeding—it is a diagnostic study for chronic conditions and would delay definitive management.

The Complete Management Algorithm

Step 1: Immediate Resuscitation (Concurrent with Imaging)

• Place two large-bore IV lines and initiate aggressive crystalloid resuscitation (1-2 L isotonic solution). 2

• Transfuse packed red blood cells when hemoglobin <70 g/L (or <80 g/L if cardiovascular disease present). 2

• Correct coagulopathy immediately: fresh frozen plasma for INR >1.5, platelets for count <50×10⁹/L. 2

Step 2: Perform CTA Immediately

• CTA should be performed without delay to localize the bleeding source before any therapeutic intervention. 1, 2

• Use a multiphase protocol (noncontrast, late arterial, and venous phases) for optimal detection. 2

Step 3: Catheter Angiography with Embolization

• If CTA is positive, proceed to catheter angiography with embolization within 60 minutes in centers with 24/7 interventional radiology. 1, 2

• Embolization achieves immediate hemostasis in 40-100% of cases and provides time to stabilize the patient. 2, 3

• Superselective embolization using polyvinyl alcohol particles (150-500 μm) or microcoils is safe and effective, with mucosal ischemia occurring in only 24% of cases (all asymptomatic). 3

Step 4: Consider Upper Endoscopy if CTA is Negative

• If no lower GI source is identified on CTA, perform upper endoscopy because 10-15% of patients with severe hematochezia have an upper GI source. 1, 2

• Risk factors for upper GI source include: brisk bleeding with shock, history of peptic ulcer disease, portal hypertension, elevated BUN/creatinine ratio, and antiplatelet drug use. 1, 2

Step 5: Surgery Only as Last Resort

• Surgery is indicated only when the patient remains unstable despite successful localization and endovascular therapy, or after failure of angiographic intervention. 2

• Blind segmental resection or emergency subtotal colectomy without prior localization carries rebleeding rates up to 33% and mortality 33-57%. 2

• Emergency total colectomy mortality is 27-33% versus ~10% when bleeding is first localized. 2

Critical Pitfalls to Avoid

• Do not rush to colonoscopy in unstable patients—this delays definitive localization with CTA and potential embolization. 2

• Do not assume maroon stool excludes an upper GI source—up to 15% of severe hematochezia originates from the upper GI tract. 2

• Do not proceed to surgery without attempting radiological localization—every effort should be made to localize bleeding through CTA and angiography before considering operative intervention. 2

• Do not place an NGT routinely—it is not indicated for suspected lower GI bleeding and does not improve outcomes. 1

Mortality Context

• Mortality in lower GI bleeding is generally related to comorbidity rather than exsanguination, with overall in-hospital mortality of 3.4%, rising to 20% in patients requiring ≥4 units of red cells. 2

• The operative mortality for emergency surgery is 10% overall, but 27-33% for total abdominal colectomy. 2