Surgery · WSES

Acute appendicitis

WSES

Source:WSES Jerusalem Guidelines for Diagnosis and Treatment of Acute Appendicitis (2020 update)

Verified Apr 2026

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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 cases^[1]
Adults with uncomplicated appendicitis (no appendicolith, no abscess, no perforation): 7–10 day antibiotic course as alternative; 30–40% recurrence at 1 year requiring delayed appendicectomy; shared decision-making
Appendicular mass / abscess management^[1]
Phlegmon: conservative IV antibiotic (Ochsner-Sherren); abscess: percutaneous drainage + IV antibiotic; interval appendicectomy debated (omit in adults without persistent symptoms; young patients with appendicolith may benefit)
Pre-operative antibiotics^[1]
Single pre-operative dose for uncomplicated; continue 3–5 days post-op for complicated (gangrenous or perforated); narrow per culture and source-control adequacy

First-line drug therapy

Drug	Class	Adult	Paediatric	Notes
Co-amoxiclav (mild community-acquired)^[1]	Aminopenicillin + beta-lactamase inhibitor	1.2 g IV pre-op; 1.2 g IV every 8 h × 24–72 h post-op for complicated; switch to oral 625 mg TDS once tolerating diet	30 mg/kg every 8 h amoxicillin component	First-line peri-operative prophylaxis and empirical for mild community-acquired; review at 48 h with cultures
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^[1]	Third-generation cephalosporin + nitroimidazole	Ceftriaxone 1–2 g IV daily + metronidazole 500 mg IV every 8 h	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)^[1]

Aminopenicillin + beta-lactamase inhibitor

Adult: 1.2 g IV pre-op; 1.2 g IV every 8 h × 24–72 h post-op for complicated; switch to oral 625 mg TDS once tolerating diet
Paediatric: 30 mg/kg every 8 h amoxicillin component

First-line peri-operative prophylaxis and empirical for mild community-acquired; review at 48 h with cultures

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^[1]

Third-generation cephalosporin + nitroimidazole

Adult: Ceftriaxone 1–2 g IV daily + metronidazole 500 mg IV every 8 h
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.

References

1.WSES Jerusalem Guidelines for Diagnosis and Treatment of Acute Appendicitis (2020 update) (2020)

Drug

Class

Adult

Paediatric

Notes

Co-amoxiclav (mild community-acquired)^[1]

Aminopenicillin + beta-lactamase inhibitor

1.2 g IV pre-op; 1.2 g IV every 8 h × 24–72 h post-op for complicated; switch to oral 625 mg TDS once tolerating diet

30 mg/kg every 8 h amoxicillin component

First-line peri-operative prophylaxis and empirical for mild community-acquired; review at 48 h with cultures

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^[1]

Third-generation cephalosporin + nitroimidazole

Ceftriaxone 1–2 g IV daily + metronidazole 500 mg IV every 8 h

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