Treatment of Rectal Abscess
The primary treatment for a rectal abscess is surgical incision and drainage, which should be performed promptly to prevent complications and progression to systemic infection. 1
Diagnosis and Assessment
- A focused medical history and complete physical examination, including digital rectal examination, should be performed to diagnose a rectal abscess 1
- Check for undetected diabetes mellitus by measuring serum glucose, hemoglobin A1c, and urine ketones, as diabetes is a common comorbidity in patients with anorectal abscesses 1
- For patients with signs of systemic infection or sepsis, request complete blood count, serum creatinine, and inflammatory markers (C-reactive protein, procalcitonin) 1
Imaging Considerations
- Imaging is not routinely required but should be considered in cases of:
- Atypical presentation
- Suspected occult supralevator abscesses
- Complex anal fistula
- Perianal Crohn's disease 1
- Preferred imaging modalities include MRI, CT scan, or endosonography based on clinical scenario and available resources 1, 2
Surgical Management
- Surgical approach with incision and drainage is the definitive treatment for all anorectal abscesses 1
- Timing of surgery should be based on the presence and severity of sepsis 1
- For fit, immunocompetent patients with small perianal abscesses without systemic signs of sepsis, outpatient management can be considered 1, 3
- For deeper or more complex abscesses, more extensive drainage may be required, potentially with multiple counter incisions 1, 4
Management of Associated Fistulas
- If a low fistula not involving sphincter muscle (subcutaneous fistula) is identified, fistulotomy can be performed at the time of abscess drainage 1, 4
- For fistulas involving sphincter muscle, place a loose draining seton rather than performing immediate fistulotomy to prevent incontinence 1, 4
- Avoid probing to search for a fistula if one is not obvious, as this may cause iatrogenic complications 1
Antibiotic Therapy
- Antibiotics are not routinely indicated for adequately drained anorectal abscesses in immunocompetent patients 1
- Antibiotic administration is recommended in the following situations:
- Presence of sepsis
- Surrounding soft tissue infection
- Immunocompromised patients
- Incomplete source control 1
- When indicated, empiric broad-spectrum antibiotic therapy should cover Gram-positive, Gram-negative, and anaerobic bacteria 1, 5
- Consider sampling of drained pus in high-risk patients or those with risk factors for multidrug-resistant organisms 1
Post-Procedure Care and Follow-up
- No definitive recommendation can be made regarding wound packing after drainage based on current evidence 1
- Monitor for signs of inadequate drainage or recurrence, which may necessitate reoperation 3
- Be vigilant for progression to necrotizing soft tissue infection, which requires aggressive debridement and systemic antibiotics 5
High-Risk Factors for Complications
- Risk factors for prolonged hospitalization, reoperation, or readmission include:
- Preoperative sepsis
- Morbid obesity
- Bleeding disorders
- Immunosuppression
- Dependent functional status 3
- The most common reason for reoperation is inadequate initial drainage requiring additional incision and drainage procedures 3