What is the management approach for a patient with Crohn's disease (CD) presenting with perianal wounds?

Management of Perianal Crohn's Disease with Wounds

A patient with Crohn's disease presenting with perianal wounds requires immediate surgical drainage of any abscesses followed by seton placement, combined with anti-TNF therapy (preferably infliximab) to control sepsis and achieve fistula healing. 1

Initial Assessment and Sepsis Control

Immediate Surgical Management

• Adequate drainage of any perianal abscess must be performed under general anesthesia without routine wound packing (packing only for short-term hemostasis if needed). 1
• Do not actively search for or probe for fistulas during emergency abscess drainage, as over-vigorous attempts can create iatrogenic tracts and complicate future management. 1
• If an obvious fistula is present without probing, insert a loose draining seton (low profile, soft material, avoiding bulky knots or firm sutures like nylon) without laying the fistula open to preserve anal function. 1
• Never perform fistulotomy or lay-open procedures in the acute setting, especially in the anterior perineum of female patients due to high risk of incontinence. 1

Diagnostic Imaging

• Contrast-enhanced pelvic MRI is the initial preferred imaging modality to evaluate fistula anatomy and identify local complications before definitive treatment planning. 1

Medical Therapy

First-Line Biological Treatment

• Start anti-TNF therapy (preferably infliximab) immediately after seton placement to control the underlying immune dysregulation and promote fistula healing. 1, 2, 3
• Infliximab dosing: 5 mg/kg IV at weeks 0,2, and 6 (induction), followed by 5 mg/kg every 8 weeks (maintenance). 4
• In fistulizing Crohn's disease, 68% of patients achieve fistula response (≥50% reduction in draining fistulas) with infliximab 5 mg/kg, and 52% achieve complete fistula closure compared to 13% with placebo. 4
• Maintain high anti-TNF trough levels to optimize response. 1

Adjunctive Medical Therapy

• Metronidazole 400 mg three times daily and/or ciprofloxacin 500 mg twice daily are appropriate first-line treatments for simple perianal fistulas, particularly when combined with biologics. 2, 3
• Consider adding azathioprine (1.5-2.5 mg/kg/day) or mercaptopurine (0.75-1.5 mg/kg/day) for dual therapy when antibiotics are insufficient. 2

Definitive Surgical Management

Timing of Seton Removal and Surgical Closure

• After good response to anti-TNF therapy, consider seton removal within 2-8 weeks to aim for closure with medication alone. 1
• Clinical closure can be achieved in up to 60% of patients with medication alone, but MRI closure is rare (<10%) with high recurrence risk. 1
• In the absence of proctitis, counsel patients for surgical closure after medical optimization. 1
• MRI closure occurs more frequently (up to 40%) after surgical closure under anti-TNF therapy, with no recurrences after long-term follow-up when complete fibrosis is achieved. 1

Surgical Options for Definitive Closure

• Surgical closure should only be attempted once infection is resolved and Crohn's disease activity is controlled. 5, 6
• Options include fistulotomy (for low fistulas only), advancement flaps, and ligation of intersphincteric fistula tract (LIFT) procedures. 6
• Avoid cutting setons, as they result in nearly 100% closure but 57% incontinence rates due to sphincter transection. 1

Refractory Disease Management

Escalation Strategies

• For patients who lose response, consider increasing infliximab to 10 mg/kg. 4
• Vedolizumab may be considered as a second-line option in patients with primary non-response to anti-TNF or contraindications, though real-world data suggests limited efficacy. 3, 5
• Ustekinumab is emerging as a second-line option for anti-TNF failures in perianal disease. 5

Surgical Diversion and Proctectomy

• Defunctioning stoma is required in 31-49% of complex perianal Crohn's disease cases when disease is rapidly progressive, gradually debilitating despite medical therapy, or causing severe quality of life impairment. 1
• Proctectomy is indicated when there is irreversible perineal destruction or symptoms limiting quality of life so markedly despite defunctioning. 1
• Risk factors for proctectomy include: age at first perianal fistula, perianal fistula at CD diagnosis, three or more fistulas during follow-up, and proctitis. 1
• Delayed perineal wound healing occurs frequently after proctectomy in perianal CD, with only 58% healed at 6 months and preoperative perianal sepsis being an independent predictor of non-healing. 1

Critical Pitfalls to Avoid

• Never delay biologic therapy in moderate-to-severe perianal disease; early introduction improves outcomes. 3
• Do not rely on corticosteroids for maintenance therapy as they are ineffective for long-term perianal disease control. 3
• Avoid surgical excision of skin tags due to high complication risk and poor wound healing in Crohn's disease. 3
• Patients who do not respond by week 14 of anti-TNF therapy are unlikely to respond with continued dosing and should have treatment reconsidered. 4
• Approximately 27% of patients experience recurrence after initial healing, with mean time to recurrence of 5.25 years, requiring long-term surveillance. 7

Multidisciplinary Approach

• Management requires coordination between gastroenterology, colorectal surgery, and radiology to optimize both medical control of inflammation and surgical management of local sepsis. 5, 6, 8
• Regular monitoring with MRI and clinical assessment is essential to evaluate response and guide further interventions. 5, 6