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gi.acute-appendicitis.core.v1PRODUCTION
gi.acute-appendicitis.core.v1

Acute Appendicitis

gastroenterologyacuteadult
Hard-required inputs
0 / 9
Care setting:

Encounter flow

12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Confirm acute abdomen scope — exclude pregnancy/pediatric pathway divergence and ruptured AAA mimics (ACG 2024)

Inputs
2
Actions
0
Advance rule
Set
Advance when

patient is hemodynamically assessable and pregnancy status known

Patient inputs (14)

Drives Alvarado/AIR scoring, pediatric vs adult pathway, neoplasm risk >40 (ACG 2024)

Pregnancy test in females; pelvic differentials (ACG 2024)

Fever as part of Alvarado; sepsis screen (ACG 2024)

Tachycardia for SIRS/sepsis screen (ACG 2024)

Hemodynamic stability; sepsis screening (ACG 2024)

Renal function for contrast CT, antibiotic dosing (ACG 2024)

Leukocytosis is core Alvarado/AIR component (ACG 2024)

Elevated CRP supports Dx; combined WBC+CRP improves sensitivity (ACG 2024)

Adult first-line imaging; sens >80%, spec >93% per SAGES 2024

Pregnancy status changes imaging modality (US/MRI over CT) (ACG 2024)

Recurrent disease changes nonop vs op decision (CODA 2-year) (ACG 2024)

Drives imaging and operative timing (ACG 2024)

Atypical presentation; lower threshold for surgery (ACG 2024)

First-line in pregnancy and pediatrics to limit radiation (ACG 2024)

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (6)

6 need judgement
  • informationallife_threateningseptic_shock_appendicitis (ACG 2024)
    Hypotension despite 30 mL/kg fluids + vasopressor need + suspected peritonitis (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereperforation_peritonitis (ACG 2024)
    Free air on imaging + peritoneal signs (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereabscess_phlegmon_complicated
    Imaging shows abscess >3-5 cm or phlegmon (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalsevereappendicitis_in_pregnancy
    Confirmed appendicitis in pregnant patient (any trimester) (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmoderateappendicolith_with_uncomplicated
    CT shows appendicolith — counsel against antibiotic-first per CODA secondary analysis (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.
  • informationalmildelderly_appendicitis_neoplasm_risk
    Appendicitis in patient ≥40 years (ACG 2024)
    Trigger could not be auto-evaluated — needs clinician judgement.

Workflow calculators

Run this disease's risk and dosing calculators inline.

RISK_STRATIFICATIONrequiredDrives risk stratification
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Recommended regimen

Acute appendicitis — surgical-first with antibiotic coverage (WSES 2020 + CODA + SAGES 2024)
axis: appendicitis_pathwaystep 1 - Step 1 — Uncomplicated appendicitis (operative)
Selected step "Step 1 — Uncomplicated appendicitis (operative)" — WSES grade 0-2; non-perforated; no abscess; surgical candidate
  • cefazolin_metronidazole
    first line
    combination_pre_op
    Cefazolin 2 g IV (3 g if >120 kg) + metronidazole 500 mg IV pre-incision • IV • one-time pre-op
    triggers: planned_appendectomy_uncomplicated
    WSES 2020 + ACS — pre-op antibiotic prophylaxis; single dose adequate for uncomplicated
    rxcui 2180
  • ceftriaxone_metronidazole
    first line
    combination
    Ceftriaxone 1-2 g IV daily + metronidazole 500 mg IV q8h • IV • daily + q8h
    triggers: delay_to_OR, planned_antibiotic_first_strategy
    Alternative empiric coverage for uncomplicated (ACG 2024)
    rxcui 2193

ed playbook — drug actions (6)

  1. 1. crystalloid
    1-2 L IV bolus (ACG 2024) • IV • PRN (ACG 2024)
    trigger: Hypovolemia/NPO (ACG 2024)
    Resuscitation (ACG 2024)
  2. 2. cefazolin + metronidazole pre-op (ACG 2024)
    Cefazolin 2 g IV + metronidazole 500 mg IV • IV • one-time pre-op
    trigger: Planned uncomplicated appendectomy (ACG 2024)
    WSES + ACS pre-op prophylaxis (ACG 2024)
  3. 3. pip-tazo for complicated
    4.5 g IV q6h • IV • q6h
    trigger: Complicated/perforated/abscess (ACG 2024)
    Broad coverage (ACG 2024)
  4. 4. ertapenem (CODA non-op) (ACG 2024)
    1 g IV daily • IV • daily
    trigger: Antibiotic-first strategy chosen (ACG 2024)
    CODA (ACG 2024)
  5. 5. analgesia
    Hydromorphone 0.5-1 mg IV q3-4h + acetaminophen 1 g IV q6h • IV • PRN/scheduled
    trigger: Pain (ACG 2024)
    Multimodal (ACG 2024)
  6. 6. ondansetron
    4 mg IV q6h PRN • IV • PRN
    trigger: Nausea (ACG 2024)
    Symptom control (ACG 2024)

Auto-drafted A&P note

ed

Subjective

- Possible entry pathways: Right lower quadrant pain (ACG 2024); Periumbilical pain migrating to RLQ (ACG 2024); Anorexia + nausea/vomiting (ACG 2024).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Acute Appendicitis** (gi.acute-appendicitis.core.v1).
Phenotype framing: Confirm appendicitis vs mesenteric adenitis, ovarian/ectopic, ureteral colic, cecal diverticulitis, Crohn ileitis (ACG 2024)
Scope: Confirm acute abdomen scope — exclude pregnancy/pediatric pathway divergence and ruptured AAA mimics (ACG 2024)

No severity triggers fired against current inputs.

Plan

Regimen axis: **Acute appendicitis — surgical-first with antibiotic coverage (WSES 2020 + CODA + SAGES 2024)** — step "Step 1 — Uncomplicated appendicitis (operative)".
1. cefazolin_metronidazole Cefazolin 2 g IV (3 g if >120 kg) + metronidazole 500 mg IV pre-incision IV one-time pre-op (combination_pre_op, first line) — WSES 2020 + ACS — pre-op antibiotic prophylaxis; single dose adequate for uncomplicated
2. ceftriaxone_metronidazole Ceftriaxone 1-2 g IV daily + metronidazole 500 mg IV q8h IV daily + q8h (combination, first line) — Alternative empiric coverage for uncomplicated (ACG 2024)

Setting playbook (ed) — Confirm appendicitis (clinical + Alvarado/AIR + imaging), risk-stratify (uncomplicated vs complicated), surgical consult, NPO + antibiotics + analgesia, OR same day (ACG 2024)
3. crystalloid 1-2 L IV bolus (ACG 2024) IV PRN (ACG 2024) — Hypovolemia/NPO (ACG 2024) (Resuscitation (ACG 2024))
4. cefazolin + metronidazole pre-op (ACG 2024) Cefazolin 2 g IV + metronidazole 500 mg IV IV one-time pre-op — Planned uncomplicated appendectomy (ACG 2024) (WSES + ACS pre-op prophylaxis (ACG 2024))
5. pip-tazo for complicated 4.5 g IV q6h IV q6h — Complicated/perforated/abscess (ACG 2024) (Broad coverage (ACG 2024))
6. ertapenem (CODA non-op) (ACG 2024) 1 g IV daily IV daily — Antibiotic-first strategy chosen (ACG 2024) (CODA (ACG 2024))
7. analgesia Hydromorphone 0.5-1 mg IV q3-4h + acetaminophen 1 g IV q6h IV PRN/scheduled — Pain (ACG 2024) (Multimodal (ACG 2024))
8. ondansetron 4 mg IV q6h PRN IV PRN — Nausea (ACG 2024) (Symptom control (ACG 2024))

Non-pharmacologic actions:
- NPO (ACG 2024)
- Surgical consult on admission (target OR same day) (ACG 2024)
- IR consult for abscess drainage if phlegmon/abscess (ACG 2024)
- Pediatric / OB consult if applicable (ACG 2024)
- Imaging within 1-2h of presentation (ACG 2024)

AVOID / contraindication checks:
- NPO_pre_op (ACG 2024)
- No_NSAID_in_septic_AKI (ACG 2024)
- Antibiotic_first_caution_with_appendicolith_higher_failure (ACG 2024)
- Carbapenem_reserved_for_severe_or_ESBL (ACG 2024)
- Single_dose_pre_op_abx_adequate_for_uncomplicated (ACG 2024)

Monitoring

Regimen monitoring:
- WBC CRP at 48h post op (ACG 2024)
- temperature q4h (ACG 2024)
- wound check post op
- diet advancement post op (ACG 2024)
- duration 24h post op uncomplicated (ACG 2024)
- duration 4 to 7 days complicated per STOP IT (ACG 2024)

Setting (ed) monitoring:
- Vitals q4h (ACG 2024)
- Pain control (ACG 2024)
- Serial abdominal exam for change (ACG 2024)

Follow-up plan: Post-op clinic 2 weeks + path review; interval appendectomy 6-8 weeks for abscess/phlegmon; colonoscopy if ≥40 (ACG 2024)
- Close-out criterion: follow-up scheduled and return precautions given

Monitoring phase: Serial abdominal exams, vitals q4h, WBC/CRP trend at 48h, diet advancement post-op, wound check (ACG 2024)

Disposition

Current setting: ed — Confirm appendicitis (clinical + Alvarado/AIR + imaging), risk-stratify (uncomplicated vs complicated), surgical consult, NPO + antibiotics + analgesia, OR same day (ACG 2024)

Disposition criteria:
- OR same day: WSES grade 0-2 uncomplicated (ACG 2024)
- IR drainage + admit: abscess/phlegmon → interval appendectomy 6-8 weeks (ACG 2024)
- Admit ICU: septic shock, severe complicated (ACG 2024)
- Discharge home: rare — only with antibiotic-first strategy with reliable follow-up (ACG 2024)

Escalation triggers (move to higher acuity):
- Septic shock → ICU + emergent OR (ACG 2024)
- Generalised peritonitis → emergent OR (ACG 2024)
- Abscess → IR drainage + delayed appendectomy (ACG 2024)
- Pregnancy with appendicitis → urgent surgical consult (lap chole still preferred 2nd trimester) (ACG 2024)

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Hypotension despite 30 mL/kg fluids + vasopressor need + suspected peritonitis (ACG 2024)
- [SEVERE] Free air on imaging + peritoneal signs (ACG 2024)
- [SEVERE] Imaging shows abscess >3-5 cm or phlegmon (ACG 2024)

Citations

- WSES 2020 Jerusalem Guidelines + SAGES 2024 Appendicitis Guideline + CODA Trial (NEJM 2020/2021) + ACS/EAST 2025 EGS Algorithm [PMID:33017106](https://pubmed.ncbi.nlm.nih.gov/33017106/)
- Cited evidence (PMID 32295644) [PMID:32295644](https://pubmed.ncbi.nlm.nih.gov/32295644/)
- Cited evidence (PMID 26080338) [PMID:26080338](https://pubmed.ncbi.nlm.nih.gov/26080338/)
- Cited evidence (PMID 30264120) [PMID:30264120](https://pubmed.ncbi.nlm.nih.gov/30264120/)

Last reconciled with current guidelines: 2026-05-22.
References
  • WSES 2020 Jerusalem Guidelines + SAGES 2024 Appendicitis Guideline + CODA Trial (NEJM 2020/2021) + ACS/EAST 2025 EGS Algorithm — PMID:33017106
  • Cited evidence (PMID 32295644) — PMID:32295644
  • Cited evidence (PMID 26080338) — PMID:26080338
  • Cited evidence (PMID 30264120) — PMID:30264120