What are the diagnostic and treatment options for recurrent hematochezia (passage of blood in stool)?

Recurrent Blood in Stool: Diagnostic and Treatment Approach

Initial Assessment and Stabilization

For recurrent hematochezia, immediate hemodynamic assessment is critical—resuscitate unstable patients with IV fluids and blood products targeting hemoglobin >7 g/dL (>9 g/dL if massive bleeding or cardiovascular disease), then proceed urgently to source localization via endoscopy or imaging. 1

Hemodynamic Resuscitation

• Packed red blood cells should maintain hemoglobin above 7 g/dL in stable patients 1
• A threshold of 9 g/dL is indicated for patients with massive bleeding, significant cardiovascular comorbidities, or possible delays in therapeutic intervention 1
• Maintain mean arterial pressure >65 mmHg while avoiding fluid overload 1

Risk Stratification

• Mortality from lower GI bleeding is typically <5%, but increases to 23% when bleeding develops during hospitalization for other conditions 1
• High-risk features include: ongoing bleeding, systolic BP <100 mmHg, heart rate >100/min, initial hematocrit <35%, gross blood on rectal exam, elevated PT, altered mental status, and unstable comorbidities 1

Diagnostic Algorithm

Step 1: Rule Out Upper GI Source

• Hematochezia with hemodynamic instability warrants upper endoscopy first, as up to 15% of serious hematochezia originates from upper GI sources 1, 2
• Insert nasogastric tube to protect airway and assess for upper GI bleeding 1

Step 2: Colonoscopy as Primary Diagnostic Tool

• Colonoscopy should be performed within 24 hours after adequate bowel preparation in hemodynamically stable patients 2
• Flexible sigmoidoscopy or colonoscopy is equally effective as anoscopy for diagnosing anorectal varices and should include full colonoscopy if risk factors for colorectal cancer exist (2.4-11% risk in rectal bleeding patients) 1
• Endoscopy has approximately 70% diagnostic yield but may miss small lesions 3

Step 3: Advanced Imaging When Colonoscopy Fails or Cannot Be Performed

CT angiography should be performed before colonoscopy in actively bleeding stable patients, as it detects bleeding at rates of 0.3 mL/min (more sensitive than angiography which requires >0.5 mL/min) and increases colonoscopic detection of vascular lesions from 20.6% to 35.7%. 1

• Tagged red blood cell scintigraphy is reserved for unexplained intermittent bleeding when other methods fail 4
• Angiography localizes bleeding in 24-70% of cases and requires active bleeding rates >0.5 mL/min 1

Treatment Based on Etiology

Inflammatory Bowel Disease

• In Crohn's disease, bleeding typically results from focal vessel erosion and may involve small bowel; preoperative localization is essential to avoid extensive resection 1, 5
• In ulcerative colitis with pancolitis, bleeding is diffuse from mucosal ulceration; endoscopic treatment is rarely possible 1
• Medical therapy resolves bleeding in most IBD cases; surgery required in <6% for massive hemorrhage 1
• Surgery is mandatory for patients with continued hemorrhage despite resuscitation or hemodynamic instability after significant resuscitation 1, 5
• Intraoperative ileoscopy should be performed if bleeding source not identified preoperatively in Crohn's disease 1

Diverticular Bleeding

• Diverticular bleeding resolves spontaneously in >75% of patients 1
• Recurrence rates: 14-38% after primary episode, with 9% at 1 year, 19% at 3 years, and 25% at 4 years 1
• Majority require <4 units of blood transfusion 1

Angiodysplasia/Angioectasias

• Overall rebleeding rate is 34%; small-bowel angioectasias have 45% rebleeding rate due to incomplete visualization and robust collateral supply 1
• Endoscopic ablation with argon plasma coagulation is first-line therapy, but endoscopic monotherapy alone is often insufficient 1
• Adjunct medical therapy with iron supplementation and somatostatin analogues (octreotide preferred over lanreotide) reduces transfusion requirements and rebleeding rates 1
• Use of transparent cap during endoscopy significantly increases angioectasia detection in small bowel 1

Endoscopic Hemostasis

Endoscopic therapy should be provided for high-risk stigmata including active bleeding, non-bleeding visible vessel, or adherent clot, using mechanical (clips), thermal, injection, or combination therapy based on bleeding etiology and lesion accessibility. 2

Transcatheter Embolization

• Technical success rates are high (98%), but clinical success is lower (63-96%) with rebleeding rates of 11-50% 1
• Superselective embolization achieves immediate hemostasis in 40-100% of diverticular bleeding with 15% rebleeding rate 1
• Rebleeding after embolization: 15% for colonic diverticular bleeding vs 45% for diffuse lesions (angiodysplasia, IBD) 1
• Major ischemic complications occur in ≤3% (up to 11% reported), with minor ischemic injury (self-limited pain, asymptomatic lactate elevation) being more common 1

Embolic Agents

• N-butyl cyanoacrylate (NBCA) demonstrates 98% technical and 86% clinical success with 6.1% complication rate, and works independently of coagulopathy 1
• Ethylene-vinyl alcohol copolymer is effective in coagulopathic patients with no outcome differences compared to non-coagulopathic patients 1
• Coils depend on intact coagulation cascade and are less effective in coagulopathy 1

Surgical Intervention

Surgery is indicated for: (1) hemodynamic instability despite resuscitation, (2) continued hemorrhage after medical/endoscopic therapy, (3) recurrent bleeding requiring multiple transfusions, or (4) when less invasive options are unavailable or have failed. 1, 2

• Preoperative localization is critical—blind segmental colectomy has 33% rebleeding rate vs 14% with angiography-directed resection 1
• Angiography-directed segmental colectomy reduces morbidity from 37% to 8.6% compared to surgery without localization 1

Prevention of Recurrent Bleeding

• NSAIDs should be avoided in patients with history of lower GI bleeding, particularly from diverticulosis or angioectasia 2
• Patients with established high-risk cardiovascular disease should NOT stop aspirin (secondary prophylaxis) during lower GI bleeding; timing of resumption depends on bleeding severity, hemostasis adequacy, and thromboembolic risk 2
• Correct coagulopathy as first step in stable patients with recurrent bleeding 1

Special Considerations

Celiac Disease

• 2-6% of asymptomatic IDA patients have celiac disease; up to 20% remain iron deficient despite strict gluten-free diet 1
• Oral iron with gluten-free diet indicated for mild villous atrophy; IV iron for severe atrophy or inadequate oral response 1

Provocative Arteriography

• Yield ranges 31-89% for identifying bleeding source in recurrent cases, but lacks standardized technique and should be used case-by-case 1
• No reports of uncontrollable hemorrhage with this technique despite precipitating active bleeding 1