START: Suspected acute appendicitis
Right iliac fossa pain, anorexia, nausea or vomiting, fever
All Pathways
Emergency MedicineEmergency
Acute Appendicitis Management (WSES)
Acute Appendicitis Management (WSES): START: Suspected acute appendicitis → Woman of reproductive age: pregnancy test first → Clinical assessment → Risk...
Pathway Overview
26 steps
Algorithm Steps
26 total
01Start 02Warning Woman of reproductive age: pregnancy test first
Urine or serum beta-hCG before imaging, surgery or discharge. Positive: exclude ectopic pregnancy.
- Positive beta-hCG and shocked: resuscitate; urgent gynaecology review (ruptured ectopic)
- Pregnant: ultrasound first, MRI if inconclusive; do not treat with antibiotics alone; involve obstetrics
- Possible torsion, PID or ovarian cyst: gynaecology review and pelvic ultrasound
03Action Clinical assessment
History, examination and blood tests. Tailor to age, sex and pregnancy status.
- Generalised peritonitis or sepsis: resuscitate, start IV antibiotics, urgent surgical review
- Give analgesia early, including opioids; it does not delay diagnosis
- Pain migrating to right iliac fossa; anorexia; vomiting; fever
- Right iliac fossa tenderness; rebound tenderness or guarding
- FBC with neutrophils, CRP, urinalysis
- Other causes: ectopic pregnancy, ovarian torsion, PID, renal colic, diverticulitis (older patients)
04Action Risk score: AIR or AAS (adults)
Adults: use AIR or AAS. Do not use Alvarado to confirm appendicitis. Children and pregnancy: do not diagnose on a score or signs alone.
- AIR: low 0-4, intermediate 5-8, high 9-12
- AAS: low 0-10, intermediate 11-15, high 16 or more
- Children: PAS or Alvarado to exclude only; add bloods and ultrasound
- Alvarado is unreliable in older adults and less sensitive in HIV
05Decision Which risk group?
Low, intermediate or high risk on the score
- Intermediate
06Action Intermediate risk: imaging
Ultrasound first in adults, children and pregnancy. Observe while you wait.
- Point-of-care or formal ultrasound first
- Adults, ultrasound negative or inconclusive: contrast-enhanced low-dose CT
- Pregnancy, ultrasound inconclusive: MRI if available
- Children, ultrasound inconclusive: MRI or local second-line imaging; avoid CT as first line
- Signs: appendix over 6 mm, periappendiceal fat stranding, appendicolith
07Decision Appendicitis confirmed?
On imaging, or on clinical grounds at senior surgical review
- If Yes
08Decision Complicated or uncomplicated?
Uncomplicated, perforation or peritonitis, or abscess or phlegmon
- Uncomplicated
09Action Uncomplicated appendicitis: discuss options
No perforation, abscess or peritonitis. Standard care is laparoscopic appendicectomy within 24 h of admission.
- Antibiotics first is a safe option in selected adults and children without appendicolith
- Not in pregnancy. Appendicolith: surgery
- Age 40 or over: CT before antibiotics first
- Explain risks: treatment can fail; recurrence up to 39% at 5 years
10Decision Antibiotics first chosen and suitable?
No appendicolith, not pregnant, informed patient choice
- If Yes
11Action Antibiotics first (non-operative)
Only if no appendicolith and not pregnant. Age 40 or over: CT first. Immunocompromised or 65 or over: senior surgical decision. Admit; IV antibiotics, then oral.
- Cover Gram-negative and anaerobic bacteria
- Agent and dose: Therapeutic Guidelines or local protocol
- Re-examine and re-score after 6-8 h
- Not improving or worse: laparoscopic appendicectomy
12Decision Improving on reassessment?
Pain, fever and inflammatory markers settling
- If Yes
13Outcome Discharge and follow-up
After surgery or successful antibiotics. Return if fever or worse pain. Age 40 or over after non-operative care: colonoscopy and interval CT.
- Eating, pain controlled, afebrile
- Return if fever, worsening pain, vomiting or wound problems
- Check histology: neoplasm needs referral
- Age 40 or over after non-operative care: colonoscopy and interval CT
If No14Action Laparoscopic appendicectomy
Preferred over open surgery, including in pregnancy, obesity and older patients. On anticoagulant or antiplatelet: plan reversal or timing with anaesthetics; do not delay surgery for peritonitis or sepsis.
- Single dose of broad-spectrum IV antibiotic within 60 min before incision
- Uncomplicated: no postoperative antibiotics
- Complicated with source control, adults: 2-3 days of antibiotics after surgery
- Complicated, children: switch to oral after 48 h; total under 7 days
- No routine drains after perforated appendicitis
- Send the appendix for histology in all patients
- Path rejoins step 13Shared downstream outcome
If No- Path rejoins step 14Shared downstream outcome
- Perforation or peritonitis
15Warning Perforation or generalised peritonitis: urgent surgery
Resuscitate. Start IV broad-spectrum antibiotics. Appendicectomy within 6-8 h.
- Adults: operate within 6 h, at most 8 h, after resuscitation
- Children with complicated appendicitis: operate within 8 h
- Path rejoins step 14Shared downstream outcome
- Abscess or phlegmon
16Action Abscess or phlegmon: choose approach
Laparoscopic surgery if advanced expertise is available. Otherwise antibiotics, with percutaneous drainage if accessible.
17Decision Operate now?
Advanced laparoscopic expertise available and patient fit
- If Yes
- Path rejoins step 14Shared downstream outcome
If No18Action Abscess or phlegmon: antibiotics with or without drainage
Non-operative care. Age 40 or over: colonoscopy and interval contrast CT (neoplasm risk 3-17%).
- IV antibiotics; percutaneous drainage if abscess is accessible
- On anticoagulant or antiplatelet: plan with the proceduralist before drainage
- Fails to settle: surgery
- Under 40 and children: no routine interval appendicectomy
- Recurrent symptoms: interval appendicectomy
- Path rejoins step 13Shared downstream outcome
If No19Action Appendicitis not confirmed: observe and reassess
Negative or inconclusive imaging.
- Negative imaging: non-operative care and reassessment
- Pain progresses or persists: diagnostic laparoscopy
- Consider gynaecological, urological and bowel causes
20Decision Symptoms settle on reassessment?
Repeat examination after negative or inconclusive imaging
- If Yes
21Outcome Settled: discharge with review
Low risk or appendicitis excluded, and symptoms settled. Review next day; return at once if pain worsens, fever or vomiting.
- Planned review next day by phone or clinic
- Return at once if pain worsens, fever or vomiting
If No22Action Pain persists or progresses: diagnostic laparoscopy
After negative imaging, persistent or progressive right iliac fossa pain needs diagnostic laparoscopy.
- Cross-sectional imaging first if not yet done (MRI in pregnancy)
- Appendicitis found: treat as above
- Appendix looks normal and no other cause: remove it
- Other cause found: treat or refer
- Path rejoins step 13Shared downstream outcome
- High
23Action High risk: urgent surgical review
Under 40 with a high-risk score (AIR 9-12, Alvarado 9-10, AAS 16 or more): CT may be omitted before diagnostic laparoscopy.
- Age 40 or over: CT first
- Symptoms over 3 days or a mass: image first (possible abscess or phlegmon)
- Possible gynaecological cause: ultrasound or gynaecology review first
- Pregnancy: ultrasound, then MRI if inconclusive
- Path rejoins step 07Shared downstream outcome
- Low
24Action Low risk: appendicitis unlikely
Observe and reassess. Look for other causes.
- Under 40, well, no warning signs: may go home with review next day by phone or clinic
- Give clear return advice: worse pain, fever, vomiting
25Decision Symptoms settle on reassessment?
Repeat examination and score
- If Yes
- Path rejoins step 21Shared downstream outcome
If No26Action Low risk, symptoms not settling: image
Cross-sectional imaging before any surgery.
- Ultrasound first; low-dose CT if negative or inconclusive (MRI in pregnancy)
- Imaging negative but pain progresses or persists: diagnostic laparoscopy
- Path rejoins step 07Shared downstream outcome
Guideline Source
Diagnosis and Treatment of Acute Appendicitis: 2025 Edition of the WSES Jerusalem Guidelines (Podda M et al., JAMA Surg 2026)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Scores support but do not replace clinical judgement; Alvarado is unreliable in older adults and less sensitive in HIV
- Pregnancy and children: ultrasound first, no antibiotic-only treatment in pregnancy; involve obstetric or paediatric surgical teams
- Antibiotic agent and dose: follow Therapeutic Guidelines or local protocol
- Older (65+), immunocompromised and obese patients: seek senior surgical input; local practice and resources vary
Applicable Regions
AUUSEUGlobal
AU: Antibiotic agent and dose per Therapeutic Guidelines (eTG) or local protocol.
Global: WSES Jerusalem guidelines: 2025 edition (abstract checked) and 2020 update (full text and Fig. 1).
Version 2Next review: 2027-09-30
Next steps
Finish the workflow by opening the most relevant calculator, then convert the session into a live account when you are ready.
Related Resources
Frequently Asked Questions
What is the Acute Appendicitis Management (WSES)?
The Acute Appendicitis Management (WSES) is a emergency clinical algorithm for Emergency Medicine. It provides a structured decision tree to guide clinical decision-making, based on Diagnosis and Treatment of Acute Appendicitis: 2025 Edition of the WSES Jerusalem Guidelines (Podda M et al., JAMA Surg 2026).
What guideline is the Acute Appendicitis Management (WSES) based on?
This algorithm is based on Diagnosis and Treatment of Acute Appendicitis: 2025 Edition of the WSES Jerusalem Guidelines (Podda M et al., JAMA Surg 2026) (DOI: 10.1001/jamasurg.2025.6218).
What are the limitations of the Acute Appendicitis Management (WSES)?
Known limitations include: Scores support but do not replace clinical judgement; Alvarado is unreliable in older adults and less sensitive in HIV; Pregnancy and children: ultrasound first, no antibiotic-only treatment in pregnancy; involve obstetric or paediatric surgical teams; Antibiotic agent and dose: follow Therapeutic Guidelines or local protocol; Older (65+), immunocompromised and obese patients: seek senior surgical input; local practice and resources vary. Individual patient factors may require deviation from these recommendations.
Get AI-Powered Analysis Alongside This Algorithm
In AttendMe.ai, the Acute Appendicitis Management (WSES) appears automatically when your clinical question matches — alongside evidence from 3M+ peer-reviewed articles.
Try AttendMe Free