In an elderly woman with massive ongoing lower gastrointestinal hemorrhage presenting with maroon stools, pallor, tachycardia, and a soft non‑tender abdomen despite adequate resuscitation, what is the initial management?

Initial Management: CT Angiography

In this hemodynamically unstable patient with massive ongoing lower GI bleeding (maroon stools, pallor, tachycardia, shock index >1), CT angiography should be performed immediately as the first diagnostic test, followed by catheter angiography with embolization if positive. 1, 2

Why Angiography is the Correct Answer

Hemodynamic Instability Dictates the Approach

• Calculate the shock index (heart rate ÷ systolic blood pressure)—a value >1 confirms hemodynamic instability and mandates immediate radiologic localization rather than endoscopy. 1, 2

• CT angiography provides the fastest and least invasive means to localize active bleeding in unstable patients, with a 94% positive rate in hemodynamically unstable lower GI bleeding. 1

• CTA can detect bleeding rates as low as 0.3 mL/min, making it superior to other modalities for rapid localization. 1

• Following positive CTA, catheter angiography with embolization should be performed within 60 minutes to maximize success rates, achieving immediate hemostasis in 40-100% of cases. 1, 2

Why the Other Options Are Incorrect

Nasogastric tube (Option A) is inappropriate:

• NGT placement is warranted only when there is medium-to-low suspicion of an upper GI source; maroon-colored stool strongly suggests a lower GI source. 3, 1
• While 10-15% of patients with severe hematochezia have an upper GI source, the soft non-tender abdomen and maroon (not bright red or melenic) stool make this less likely. 3
• NGT lavage can be misleading if only clear fluid without bile returns. 3

Colonoscopy (Option C) is contraindicated in this unstable patient:

• Colonoscopy should NOT be performed as the initial approach when shock index >1 or the patient remains unstable after resuscitation. 1, 2
• Colonoscopy requires adequate bowel preparation (taking hours) and is reserved for stable patients after bleeding localization and hemodynamic optimization. 1
• The British Society of Gastroenterology explicitly recommends against urgent colonoscopy in unstable patients. 1

Barium enema (Option D) has no role:

• Barium enema is obsolete in acute GI bleeding—it provides no therapeutic benefit, obscures subsequent imaging, and delays definitive intervention.
• No modern guidelines recommend barium studies for acute lower GI bleeding.

Complete Management Algorithm for This Patient

Immediate Resuscitation (Concurrent with Diagnostic Workup)

• Establish two large-bore IV lines (≥18-gauge) and begin aggressive crystalloid resuscitation. 2

• Transfuse packed red blood cells using restrictive thresholds: hemoglobin trigger 70 g/L (target 70-90 g/L) for patients without cardiovascular disease, or 80 g/L (target ≥100 g/L) for those with cardiovascular disease. 1, 2

• Correct coagulopathy immediately: administer prothrombin complex concentrate plus vitamin K if INR >1.5 (for warfarin users), and transfuse platelets if count <50,000/µL. 1, 2

• Admit to ICU given persistent hemodynamic instability despite resuscitation. 1, 2

Diagnostic and Therapeutic Sequence

1. Perform CT angiography immediately—do not delay for bowel preparation or endoscopy. 1, 2

2. If CTA is positive, proceed directly to catheter angiography with embolization within 60 minutes. 1, 2

3. If CTA is negative but bleeding continues, consider upper endoscopy to exclude an upper GI source (10-15% of severe hematochezia). 3, 1, 2

4. Reserve colonoscopy for after the patient is stabilized, adequately resuscitated, and bowel-prepped—typically on the next available inpatient list, not urgently. 1

When Surgery Becomes Necessary

• Surgery is indicated only when the patient remains unstable despite successful localization and endovascular therapy, or requires >6 units of packed red blood cells without diagnosis despite all diagnostic modalities. 1, 2

• Blind segmental resection without preoperative localization carries rebleeding rates up to 33% and mortality of 33-57%—always attempt localization before surgery. 1, 2

• Emergency subtotal colectomy has mortality rates of 27-33% and should be avoided unless all other options are exhausted. 1, 2

Critical Pitfalls to Avoid

• Do not rush to colonoscopy in unstable patients—this delays definitive localization with CTA and potential life-saving embolization. 1

• Do not perform blind surgical resection without radiologic localization—mortality and rebleeding rates are unacceptably high. 1, 2

• Do not assume all maroon stools are from the colon—up to 15% of severe hematochezia originates from the upper GI tract, so maintain a high index of suspicion. 3, 1

• Mortality in lower GI bleeding is primarily related to comorbidities rather than exsanguination: overall in-hospital mortality is 3.4%, but rises to 20% in patients requiring ≥4 units of red cells. 1, 2