What is the treatment for a rectal abscess?

Treatment of Rectal Abscess

Surgical incision and drainage is the definitive treatment for all anorectal abscesses. 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, 2
• 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 1
  • Suspected occult supralevator abscesses 1
  • Perianal Crohn's disease 1
• Preferred imaging modalities include MRI, CT scan, or endosonography based on clinical scenario and available resources 1, 3

Surgical Management

• Incision and drainage is the cornerstone of treatment for all anorectal abscesses 1, 4
• Timing of surgery should be based on the presence and severity of sepsis 1
• For deeper or more complex abscesses, more extensive drainage may be required, potentially with multiple counter incisions 1
• The approach to drainage depends on the location:
  • Perianal/ischiorectal abscesses: External approach 1, 5
  • Rectal wall abscesses: May require transrectal drainage 3

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, 6
• 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:
  • Presence of sepsis 1, 7
  • Immunocompromised patients 1
  • Patients with diabetes mellitus or history of alcohol abuse (higher risk of invasive infection) 2
• When indicated, empiric broad-spectrum antibiotic therapy should cover Gram-positive, Gram-negative, and anaerobic bacteria 1, 2
• 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
• Post-drainage wound care should include:
  • Sitz baths with warm water for 10-15 minutes, 2-3 times daily 6
  • Gentle cleaning of the perianal area after each bowel movement 6
  • Application of non-adherent dressing if significant drainage is present 6

Warning Signs Requiring Immediate Attention

• Increasing pain, swelling, or redness around the perianal area 6
• Fever or other signs of systemic infection 6, 7
• Significant increase in drainage or purulent discharge 6

Special Considerations

• Patients with diabetes mellitus and history of alcohol abuse are at higher risk for invasive infections and require more aggressive management 2
• Necrotizing soft-tissue infections can develop as a complication of rectal abscess and require aggressive surgical debridement, broad-spectrum antibiotics, and possibly diverting colostomy 7
• Rare cases of ischiorectal abscesses forming sinuses with the spinal canal have been reported and require specialized management 5