How should I evaluate and manage hematochezia in a patient with Crohn’s disease?

Hematochezia in Crohn's Disease: Evaluation and Management

Significant bleeding in Crohn's disease is rare (occurring in only 1-5% of patients), and your immediate priority is determining hemodynamic stability, which dictates whether the patient requires emergency surgery or can undergo diagnostic evaluation first. 1

Initial Assessment and Hemodynamic Stratification

Assess hemodynamic status immediately upon presentation:

• Calculate shock index (heart rate/systolic blood pressure); values >1 indicate active bleeding requiring hospital-based intervention 2
• Check orthostatic vital signs in stable patients; orthostatic hypotension indicates significant blood loss requiring ICU admission 2
• Establish two large-bore IV lines and begin aggressive fluid resuscitation with 1-2 liters of normal saline 2
• Use restrictive transfusion thresholds: hemoglobin trigger of 70 g/L (target 70-90 g/L) for stable patients without cardiovascular disease, or 80 g/L (target 100 g/L) for those with cardiac disease or massive bleeding 2

Management Algorithm Based on Hemodynamic Status

Hemodynamically Unstable Patients (Shock Despite Resuscitation)

Proceed directly to emergency surgical exploration via laparotomy if the patient remains unstable despite significant resuscitation. 1, 3

• Surgery is mandatory when hemorrhagic shock persists after aggressive resuscitation or blood transfusion exceeds 6 units 2
• Perform intra-operative ileoscopy during surgical exploration to identify the bleeding source if not identified pre-operatively 1
• The bleeding in Crohn's disease typically results from focal erosion of an intestinal vessel and is more localized than in ulcerative colitis 3

Hemodynamically Stable Patients (After Resuscitation)

Follow this sequential diagnostic approach:

1. Perform colonoscopy and esophagogastroduodenoscopy first to localize the bleeding source 3

   • Colonoscopy identifies the bleeding source in 60% of cases 4
   • The bleeding lesion is an ulcer in 95% of cases, most often in the left colon 4
   • Hematochezia is more frequent in colonic disease (85%) than isolated small bowel disease (15%) 4

2. Obtain CT angiography if endoscopy is non-diagnostic 1, 2, 3

   • CT angiography has 79-95% sensitivity and 95-100% specificity for detecting active bleeding 2
   • Identifies bleeding at rates as low as 0.3 mL/min (more sensitive than conventional angiography which requires >0.5 mL/min) 1
   • Can identify bleeding sources in upper GI tract, small bowel, or colon 2

3. Consider capsule endoscopy or double-balloon enteroscopy for small bowel sources 5

   • Critical when standard endoscopy and imaging fail to identify the source
   • Small bowel strictures with ulceration can present with hemorrhagic shock as the initial manifestation of Crohn's disease 5

4. Proceed to catheter angiography with embolization within 60 minutes if CT angiography is positive 2

   • Super-selective angiographic embolization achieves immediate hemostasis in 40-100% of cases 1, 3
   • Rebleeding occurs in approximately 15% of cases 1, 3
   • Risk of bowel ischemia following embolization is 1-4% 1

5. Use nuclear medicine labeled red cell scans if bleeding is not detected by angiography 1

Critical Clinical Considerations

Exclude common causes of gastrointestinal bleeding before attributing bleeding to Crohn's disease:

• Perform stool cultures for entero-invasive bacterial infections and Clostridium difficile assay in all patients with acute flares 1
• Consider cytomegalovirus disease in moderate to severe colitis, particularly with corticosteroid-refractory disease; obtain colonic biopsies for H&E staining, immunohistochemistry, or quantitative tissue PCR 1
• Evaluate for tuberculosis in patients from endemic areas, as intestinal TB can mimic Crohn's disease; haematochezia is more common in Crohn's disease than TB 1

Recognize that hemorrhage in Crohn's disease has unique characteristics:

• Hemorrhage reveals Crohn's disease as the initial presentation in 23.5% of cases 4
• Bleeding occurs during disease flare-up in only 35% of cases; two-thirds occur during quiescent disease 4
• Recurrent hemorrhage occurs in 35% of patients within a mean of 3 years 4
• Mortality from hemorrhagic Crohn's disease is rare when managed appropriately 4

Surgical Indications

Surgery is indicated when:

• Continued hemorrhage despite resuscitation 1, 2
• Blood transfusion requirement exceeds 6 units 2
• Failure of endoscopic and interventional radiology measures 1
• Other indications for resection of diseased bowel exist 1

Surgical approach considerations:

• Use laparoscopic approach in hemodynamically stable patients if local expertise exists 1
• Use open approach in hemodynamically unstable patients to reduce operating time 1
• Avoid blind segmental resection, which has rebleeding rates as high as 33% and mortality of 33-57% 2

Common Pitfalls to Avoid

• Do not assume all hematochezia in Crohn's disease is from active inflammation—exclude infectious causes, particularly C. difficile and CMV 1
• Do not delay surgical exploration in unstable patients—mortality increases with delayed surgery in hemodynamically unstable patients 1
• Do not perform blind colectomy without source localization—all efforts to identify the bleeding source should be made pre-operatively to avoid extensive unnecessary resection 1, 3
• Do not overlook small bowel sources—consider capsule endoscopy or double-balloon enteroscopy when standard evaluation is negative 5