An elderly woman with lower GI bleeding, a diffusely tender abdomen, and fresh blood on physical examination, remains unstable despite blood transfusions, what is the most appropriate next step in management?

Management of Hemodynamically Unstable Lower GI Bleeding with Diffuse Abdominal Tenderness

In this elderly woman with hemodynamic instability despite transfusion, diffuse abdominal tenderness, and ongoing lower GI bleeding, the most appropriate next step is immediate CT angiography (CTA), NOT emergency colonoscopy or laparotomy. 1, 2

Critical Initial Assessment

Calculate the shock index immediately (heart rate/systolic blood pressure). A shock index >1 confirms hemodynamic instability and mandates urgent intervention rather than colonoscopy. 2, 3

The diffuse abdominal tenderness is a critical red flag that suggests either:

• Bowel ischemia/infarction
• Perforation
• Severe inflammatory process

This makes colonoscopy potentially dangerous and contraindicated until the source is localized. 2

Why CT Angiography First

CTA provides the fastest and least invasive means to localize bleeding in hemodynamically unstable patients, with a 94% positive rate in unstable lower GI bleeding. 1, 2 This allows you to:

• Rapidly identify the bleeding source without bowel preparation 1, 2
• Assess for complications like ischemia or perforation that explain the diffuse tenderness 2
• Guide immediate therapeutic intervention (angiography with embolization) 1
• Avoid the risks of colonoscopy in an unstable patient with peritoneal signs 2

Why NOT Emergency Colonoscopy

Emergency colonoscopy is explicitly contraindicated in patients with shock index >1 or hemodynamic instability. 2, 4 The reasons are:

• Requires time-consuming bowel preparation that delays definitive diagnosis 2, 5
• Cannot be safely performed in unstable patients 2, 4
• The diffuse abdominal tenderness suggests possible ischemia or perforation, making colonoscopy dangerous 2
• Colonoscopy should only be performed after stabilization or successful localization via CTA 1, 2

Why NOT Immediate Laparotomy

No patient should proceed to emergency laparotomy unless every effort has been made to localize bleeding by radiological and/or endoscopic modalities. 1 The evidence is clear:

• Blind segmental resection has rebleeding rates as high as 33% and mortality rates of 33-57% 1
• Emergency subtotal colectomy has mortality rates of 27-33% 1
• Even in unstable patients, CTA and angiography should be attempted first to allow targeted treatment 1, 2
• Surgery is reserved only for patients who fail angiographic intervention or continue to deteriorate despite all localization attempts 2

The Correct Management Algorithm

Step 1: Continue Aggressive Resuscitation

• Use restrictive transfusion thresholds: Hb trigger 80 g/L (target ≥100 g/L) given likely cardiovascular disease in elderly patients 1, 4
• Correct coagulopathy if present (FFP for INR >1.5, platelets for <50,000/µL) 2

Step 2: Immediate CTA

• Perform within minutes, not hours 1, 2
• Do not delay for bowel preparation or additional resuscitation if patient remains unstable 2

Step 3: Catheter Angiography with Embolization

• If CTA is positive, proceed to catheter angiography within 60 minutes 1
• Embolization provides time to stabilize the patient and prepare for surgery if ultimately needed 1

Step 4: Consider Upper Endoscopy

• If no lower GI source identified on CTA, consider upper GI bleeding (up to 11% of hematochezia with instability is from upper GI source) 2

Step 5: Surgery Only as Last Resort

• Reserved for failure of angiographic intervention or continued deterioration despite all attempts at localization 1, 2
• Requires precise localization to avoid blind resection 1

Critical Pitfalls to Avoid

Do not rush to colonoscopy in unstable patients - this delays definitive localization and potential embolization. 2

Do not perform laparotomy without localization - mortality rates are prohibitively high (27-33%) with blind resection. 1

Do not ignore the diffuse abdominal tenderness - this suggests ischemia or perforation and makes colonoscopy dangerous until imaging excludes these complications. 2

Remember that mortality in lower GI bleeding is related to comorbidity (3.4% overall, 20% with ≥4 units transfused), not exsanguination - aggressive localization and targeted therapy improve outcomes more than rushing to surgery. 1, 2