Red Flags
- Suspected perforation, generalised peritonitis, or appendicular abscess — emergency surgery; broad-spectrum antibiotic; admit[1]
- Sepsis or septic shock — sepsis pathway with broad-spectrum IV antibiotic within 1 h, fluids, lactate, urgent source control[1]
- Pregnancy with suspected appendicitis — laparoscopic appendicectomy at any trimester; expedite imaging and surgery to reduce fetal loss from delay[1]
- Right iliac fossa pain in elderly with weight loss or anaemia — exclude colorectal malignancy presenting as appendiceal obstruction[1]
First-line treatment
Interventions
- Laparoscopic appendicectomy as gold standard[1]Preferred over open in adults, children, obese, elderly, complicated, and pregnancy; lower wound infection, shorter stay, faster recovery; expert-dependent in resource-limited settings
- Antibiotic-only management for selected uncomplicated casesDiscuss antibiotic-only management with carefully selected adults with uncomplicated appendicitis and no appendicolith, including the risk of failure, missed complicated disease, and recurrence up to 39% at 5 years. Start IV antibiotics with oral switch according to clinical condition. WSES 2020 advises against nonoperative treatment during pregnancy; it does not prescribe one universal 7–10-day course. [2]
- Appendicular mass / abscess managementFor appendiceal phlegmon or abscess, antibiotics with percutaneous drainage if accessible are an option; drainage is not routinely required. Advanced laparoscopic treatment is an alternative where expertise is available. Avoid routine interval appendectomy in young adults under 40 and children after successful nonoperative treatment, but recommend appendectomy for recurrent symptoms. For adults≥40 treated nonoperatively, WSES suggests colonic screening and interval contrast CT (weak recommendation,2 C). [2]
- Pre-operative antibioticsGive a single broad-spectrum antibiotic dose 0–60 minutes before incision for appendectomy. Do not give postoperative antibiotics for uncomplicated appendicitis. For complicated disease, postoperative treatment depends on source control and clinical circumstances; after adequate source control, avoid extending beyond 3–5 days. Selected adults may stop after 24 hours. [2]
First-line drug therapy
| Drug | Class | Adult | Paediatric | Notes |
|---|---|---|---|---|
| Co-amoxiclav (mild community-acquired) | Aminopenicillin + beta-lactamase inhibitor | For non-critically ill adults with community-acquired intra-abdominal infection, WSES 2020 lists amoxicillin/clavulanate 1.2–2.2 g every 6 hours. This passage does not establish a universal postoperative or oral-switch regimen. [2] | 30 mg/kg every 8 h amoxicillin component | Co-amoxiclav is a listed empiric regimen for non-critically ill adults with community-acquired intra-abdominal infection in the WSES 2020 antibiotic discussion; it is not presented as the sole preferred appendectomy prophylactic agent. [2] |
| Piperacillin-tazobactam (complicated)[1] | Beta-lactam + beta-lactamase inhibitor | 4.5 g IV every 6–8 h | Per local protocol | Complicated appendicitis (perforated, peritonitis, sepsis); broad gram-positive, gram-negative, anaerobic; renal dose adjustment |
| Ceftriaxone + metronidazole | Third-generation cephalosporin + nitroimidazole | For non-critically ill adults with community-acquired intra-abdominal infection, the listed regimen is ceftriaxone 2 g every 24 hours PLUS metronidazole 500 mg every 6 hours. Do not apply this as a universal postoperative duration or pediatric regimen. [2] | Ceftriaxone 50–80 mg/kg/day; metronidazole 7.5 mg/kg every 8 h | Alternative for uncomplicated and selected complicated; oral switch when improving |
| Meropenem (severe / ESBL risk)[1] | Carbapenem | 1 g IV every 8 h | 20 mg/kg every 8 h | Reserve for severe sepsis or known ESBL; renal dose adjustment |
Co-amoxiclav (mild community-acquired)
Aminopenicillin + beta-lactamase inhibitor
- Adult
- For non-critically ill adults with community-acquired intra-abdominal infection, WSES 2020 lists amoxicillin/clavulanate 1.2–2.2 g every 6 hours. This passage does not establish a universal postoperative or oral-switch regimen. [2]
- Paediatric
- 30 mg/kg every 8 h amoxicillin component
Co-amoxiclav is a listed empiric regimen for non-critically ill adults with community-acquired intra-abdominal infection in the WSES 2020 antibiotic discussion; it is not presented as the sole preferred appendectomy prophylactic agent. [2]
Piperacillin-tazobactam (complicated)[1]
Beta-lactam + beta-lactamase inhibitor
- Adult
- 4.5 g IV every 6–8 h
- Paediatric
- Per local protocol
Complicated appendicitis (perforated, peritonitis, sepsis); broad gram-positive, gram-negative, anaerobic; renal dose adjustment
Ceftriaxone + metronidazole
Third-generation cephalosporin + nitroimidazole
- Adult
- For non-critically ill adults with community-acquired intra-abdominal infection, the listed regimen is ceftriaxone 2 g every 24 hours PLUS metronidazole 500 mg every 6 hours. Do not apply this as a universal postoperative duration or pediatric regimen. [2]
- Paediatric
- Ceftriaxone 50–80 mg/kg/day; metronidazole 7.5 mg/kg every 8 h
Alternative for uncomplicated and selected complicated; oral switch when improving
Meropenem (severe / ESBL risk)[1]
Carbapenem
- Adult
- 1 g IV every 8 h
- Paediatric
- 20 mg/kg every 8 h
Reserve for severe sepsis or known ESBL; renal dose adjustment
Safety-net
- After surgery: most return to normal activity within 1–2 weeks (laparoscopic) or 4 weeks (open); persistent fever, increasing pain, or wound discharge — same-day review[1]
- If on antibiotic-only management: complete the full course; recurrence rate is 30–40% within 1 year and may need delayed surgery[1]
- Severe abdominal pain with fever, vomiting, or peritonism — emergency department; perforated appendicitis carries higher complication rate[1]
Referral criteria
- All suspected acute appendicitisGeneral surgery for evaluation and management[1]
- Perforation, peritonitis, sepsis, or appendicular abscessEmergency department with surgery and ICU[1]
- Pregnancy with suspected appendicitisJoint surgery and obstetric clinic; expedite[1]
- Elderly with right iliac fossa mass or atypical featuresSurgery with imaging and colonoscopy to exclude malignancy[1]
Clinical summary
Diagnosis with risk-scoring + imaging, antibiotic vs surgical management, and special situations (children, pregnancy, complicated) for acute appendicitis.