What are the typical presentation and treatment of a Crohn’s disease–related internal fistula?

Crohn's Disease-Related Internal Fistulae: Presentation and Management

The most common presentation of Crohn's disease-related internal fistulae involves small bowel to small bowel fistulation (enteroenteric fistulae), not florid sepsis, Crohn's disease flare-up, or immediate need for surgical intervention. 1

Types and Prevalence

• Internal fistulae occur in 5-15% of patients with Crohn's disease 2, 1
• The most common type is enteroenteric (small bowel to small bowel) fistulation 1
• Other types include enterocolic, enterovesical, and rectovaginal fistulae 1

Clinical Presentation

• Most patients present with symptoms related to the underlying Crohn's disease rather than with florid sepsis 3
• Symptoms vary depending on the organs involved and may include:
  • Diarrhea and malabsorption (enteroenteric fistulae) 1
  • Recurrent urinary tract infections (enterovesical fistulae) 3
  • Passage of stool through the vagina (rectovaginal fistulae) 3
• Internal fistulae often develop in the context of other complications such as intra-abdominal abscess and luminal strictures 3

Diagnostic Approach

• Multi-modal assessment is required, including:
  • Cross-sectional imaging (MRI is preferred) 4
  • Endoscopy to evaluate for concomitant inflammation 4
  • Examination under anesthesia for perianal fistulae 4

Management Principles

Medical Management

• Asymptomatic fistulae generally do not require treatment 2, 5
• For symptomatic fistulae, medical therapy should be considered before surgical intervention 3
• Anti-TNF therapy (infliximab) has shown efficacy in treating fistulizing Crohn's disease:
  • In the ACCENT II trial, infliximab was effective for enterocutaneous fistulae 6
  • 68% of patients receiving 5 mg/kg infliximab showed fistula response 6
  • 38% of patients on maintenance infliximab had complete fistula closure at week 54 6

Surgical Management

• Surgery is indicated for:

  • Symptomatic fistulae that fail to respond to medical therapy 3
  • Fistulae associated with abscess formation 3
  • High-output enterocutaneous fistulae 3
  • Fistulae causing significant morbidity 2

• Surgical approach should be conservative and does NOT require excision of both organs involved 7

• The standard surgical approach involves:

  • Resection of the diseased intestinal segment that is the source of the fistula 7
  • The affected secondary organ can often be treated with simple closure of the defect rather than resection 7
  • For enterocutaneous fistulae, debridement of the fistulous tract after resection of the diseased bowel 7

Timing of Surgery

• Immediate surgical intervention is NOT required once diagnosis is made 3
• Surgery should be delayed until:
  • Sepsis is controlled 4
  • Nutritional status is optimized 3
  • Inflammation is medically controlled when possible 3

Special Considerations

• For complex fistulae, a multidisciplinary approach involving gastroenterologists and surgeons is recommended 3
• Before any surgical intervention, any associated abscesses must be drained 4
• Concomitant medical therapy with immunosuppressives is advised for better outcomes 3

Common Pitfalls to Avoid

• Performing immediate surgery without adequate control of sepsis and optimization of nutritional status 3
• Extensive resection of both organs involved in the fistula when conservative approaches may be sufficient 7
• Failure to drain associated abscesses before definitive treatment 4
• Overlooking the need for medical therapy to control underlying Crohn's disease activity 3