What is the treatment for appendicitis with an abscess?

Treatment of Appendicitis with Abscess

For appendicitis with abscess, the recommended first-line treatment is non-operative management with antibiotics and percutaneous drainage, if available, especially in settings where advanced laparoscopic expertise is not accessible. 1

Initial Management

• Percutaneous image-guided drainage combined with appropriate antibiotic therapy is the preferred first-line intervention for appendicitis with abscess 1
• In settings where percutaneous drainage is not available or feasible, surgical intervention should be considered 1
• For smaller abscesses (maximum diameter of 3-6 cm), antibiotics alone without drainage may be sufficient 1
• Larger abscesses generally require percutaneous drainage in addition to antibiotics 1, 2

Antibiotic Therapy

• For stable patients with appendiceal abscess, recommended antibiotic regimens include:
  • Piperacillin/tazobactam 3.375 grams IV every 6 hours for 7-10 days 3, 1
  • Alternative regimens include metronidazole plus a broad-spectrum antibiotic 4
• For critically ill patients, consider:
  • Meropenem, doripenem, or imipenem/cilastatin, plus metronidazole 4
  • Add vancomycin if MRSA is suspected 4
• Antibiotic duration should typically be 3-5 days after adequate source control is achieved 1

Percutaneous Drainage Procedure

• CT-guided percutaneous drainage has shown clinical and technical success rates of approximately 90% with no procedure-related complications 2
• Risk factors for failed percutaneous drainage include:
  • Large, poorly defined periappendiceal abscess 2
  • Extraluminal appendicolith on CT images 2
  • Patient complexity, female sex, and earlier drainage 5
• Approximately 25% of patients may fail management with percutaneous drainage alone and require subsequent surgical intervention 5

Surgical Management

• Laparoscopic approach is the treatment of choice for patients with complicated appendicitis with phlegmon or abscess where advanced laparoscopic expertise is available 1
• Operative management may be associated with shorter hospital stays, reduced need for readmissions, and fewer additional interventions than conservative treatment in experienced hands 1
• However, surgical management has shown higher complication rates (32%) compared to non-surgical management (3%) in some studies 6

Follow-up Management

• Routine interval appendectomy after successful non-operative management is not recommended for young adults (<40 years old) and children 1
• Interval appendectomy should be performed only for patients with recurrent symptoms 1
• The recurrence rate after non-surgical treatment ranges from 12% to 24% 1
• For patients ≥40 years old with complicated appendicitis treated non-operatively, both colonoscopy and interval full-dose contrast-enhanced CT scan are recommended for follow-up due to the higher incidence (3-17%) of appendicular neoplasms in this age group 1

Pitfalls and Caveats

• Failure to recognize patients who require surgical intervention despite initial non-operative management can lead to increased morbidity 1
• CT findings of distant free air do not necessarily mandate immediate surgical approach in hemodynamically stable patients 1
• Routine use of intra-operative irrigation during appendectomy does not prevent intra-abdominal abscess formation and may be avoided 1
• Prolonged antibiotic therapy beyond 3-5 days post-operatively in cases with adequate source control is not recommended and may contribute to antibiotic resistance 1