12-phase flow (12)

1. 1FRAME
   Frame as the peritonsillar cellulitis → abscess continuum: severe unilateral sore throat + trismus + muffled voice + uvular deviation. Distinguish from symmetric pharyngitis/tonsillitis, infectious mononucleosis, epiglottitis, retropharyngeal abscess, and odontogenic deep-space infection. Airway, deep-space surgical source control, sepsis, and EBV-mono pathways are routed OUT, not authored here.
   advance: PTA scope confirmed; airway/deep-space/sepsis/mono concerns flagged for routing by engine_id
2. 2ENTRY
   Recognise the severe-unilateral-sore-throat-with-trismus, hot-potato-voice/uvular-deviation, drooling, recurrent-PTA, or partially-treated-tonsillitis-not-improving entry; record laterality up front (symmetric throat argues against PTA).
   inputs: sore_throat_laterality
   actions: calc.centor
   advance: entry trigger present; laterality and Centor recorded
3. 3CONTEXT
   Build the cellulitis-vs-abscess pre-test prior: trismus, uvular deviation + soft-palate fullness, hot-potato voice, fever; comorbidity (diabetes/immunocompromise), recurrence history. This phase assigns the pre-POCUS abscess probability.
   inputs: trismus_present, uvular_deviation_soft_palate_fullness, voice_quality_hot_potato, temperature, immunocompromise
   actions: workup.lymphadenopathy
   advance: cardinal-feature set + pretest abscess prior assigned
4. 4RED_FLAGS
   Recognise the dangerous extensions: airway compromise (stridor/tripod/air-hunger) → route to ent.epiglottitis.core.v1; parapharyngeal/retropharyngeal spread / torticollis / neck swelling → route to ent.retropharyngeal-abscess.core.v1; descending mediastinitis (very high CRP, chest/back pain) → deep-space + thoracic; Lemierre (rigors, neck-vein tenderness, septic pulmonary emboli); systemic toxicity / qSOFA≥2 / hypotension → route to id.sepsis.core.v1. Recognised here, NOT managed here.
   inputs: airway_compromise_features, neck_swelling_torticollis_extension, sbp
   actions: workup.airway_distress, calc.qsofa, calc.news2
   advance: airway / deep-space / mediastinitis / Lemierre / sepsis screened and routed by engine_id if positive
5. 5INITIAL_WORKUP
   Targeted labs only: CBC + CRP (suppuration + mediastinitis-risk anchor — Hu Medicina 2022); CMP for hydration/renal dosing in the drooling/poor-intake patient; coagulation panel if drainage planned in an anticoagulated/bleeding-diathesis patient; consider Monospot/EBV serology if bilateral tonsillar exudate + posterior cervical nodes + splenomegaly suggest coexisting mononucleosis. Throat/aspirate culture only at drainage (Fusobacterium-aware — Klug Dan Med J 2017).
   inputs: wbc, crp
   actions: panel.cbc, panel.inflammation, panel.cmp, panel.coag
   advance: baseline labs sent; hydration + bleeding risk assessed
6. 6BRANCHING_WORKUP
   Cellulitis-vs-abscess decision tree: clinical exam alone is only ~75% sensitive / ~50% specific (Kim Acad Emerg Med 2023) → intraoral or transcervical POCUS (pooled sens 86% / spec 76%; LR+ 3.5, LR− 0.19) as the discriminator and aspiration guide; contrast CT neck if POCUS equivocal, trismus precludes intraoral exam, or parapharyngeal/retropharyngeal/mediastinal extension suspected. Peritonsillar cellulitis (no drainable collection) → antibiotics + observe, no drainage.
   inputs: pta_pocus_or_ct_neck
   actions: workup.cellulitis_necfasc, workup.bacterial_meningitis
   advance: abscess confirmed/excluded by POCUS or CT, or empiric cellulitis pathway entered
7. 7DIFFERENTIAL
   Terminal differential with pivot findings: peritonsillar abscess vs peritonsillar cellulitis (drainable collection on POCUS/CT pivot) vs severe tonsillitis/pharyngitis (symmetric, no uvular deviation, no trismus pivot) vs infectious mononucleosis (bilateral exudate + posterior cervical nodes + splenomegaly + atypical lymphocytes pivot — route to ent.pharyngitis.core.v1) vs epiglottitis (rapid airway, stridor, minimal oral findings, "thumbprint" pivot — route to ent.epiglottitis.core.v1) vs retropharyngeal abscess (neck stiffness, posterior pharyngeal bulge, CT pivot — route to ent.retropharyngeal-abscess.core.v1) vs odontogenic/dental deep-space infection (molar source, floor-of-mouth pivot).
   advance: single best diagnosis selected; PTA-on-mononucleosis coexistence flagged
8. 8RISK_STRATIFICATION
   Severity → disposition: uncomplicated drainable PTA, tolerating oral intake, no airway/deep-space/sepsis flag → outpatient drainage + oral antibiotics; trismus precluding bedside drainage, dehydration, failed outpatient drainage, immunocompromise, suspected deep-space spread, qSOFA≥2/NEWS2 high → admit / OR. SIRS / qSOFA layered for the systemic-toxicity upgrade.
   inputs: temperature, sbp
   actions: calc.qsofa, calc.sirs, calc.news2
   advance: severity class + disposition track assigned
9. 9TREATMENT
   Source control + antimicrobial + adjunct: (1) drain a confirmed abscess — needle aspiration OR incision-and-drainage (Chang Cochrane 2016 — I&D lower recurrence RR 3.74 favouring I&D; aspiration less painful); quinsy/à-chaud tonsillectomy if recurrent/failed drainage/concurrent tonsillectomy indication (Rosi-Schumacher Int J Pediatr Otorhinolaryngol 2023 — equivalent outcomes); (2) anaerobe + GAS-cover antibiotic, Fusobacterium-aware (ampicillin/sulbactam IV or amoxicillin/clavulanate PO; clindamycin if penicillin-allergic; add/substitute metronidazole for anaerobe cover; penicillin G for confirmed GAS); (3) adjunct single-dose IV dexamethasone (Hur Laryngoscope 2018 — faster fever/pain/intake recovery); (4) hydration + analgesia. Antibiotic-safety gating by pregnancy/allergy/renal.
   inputs: penicillin_allergy, anticoagulation_or_bleeding_diathesis, pregnancy
   actions: protocol.septic_shock
   advance: abscess drained (or cellulitis treated medically); antibiotic + steroid + hydration started; ENT engaged
10. 10DISPOSITION
    Outpatient: successful bedside drainage, tolerating oral intake/analgesia, no red flag, reliable follow-up → discharge on oral antibiotics + ENT review. Admit: trismus precluding drainage, dehydration/can't tolerate PO, immunocompromise, airway/deep-space/sepsis flag, failed outpatient drainage, age extremes/unreliable follow-up. Airway/deep-space/sepsis → admit and route OUT by engine_id.
    inputs: temperature, sbp
    advance: disposition documented; route-out completed if airway/deep-space/sepsis positive
11. 11MONITORING
    Expect symptomatic improvement within 24-48 h of adequate drainage + antibiotics; persistent fever, trismus, or pain at 24-48 h → re-image for re-accumulation / parapharyngeal-retropharyngeal extension / wrong-spectrum, do not silently extend antibiotics. Watch for delayed Lemierre (rigors, pleuritic chest pain, neck-vein tenderness) and post-drainage bleeding (Chang Cochrane 2016 — post-I&D bleed ~3.6%).
    inputs: crp, wbc
    actions: panel.inflammation
    advance: objective improvement by 24-48 h, OR re-evaluation/re-imaging triggered
12. 12FOLLOWUP
    Smoking-cessation counselling (smoking is an independent PTA risk factor — Klug Dan Med J 2017); ENT follow-up; recurrence counselling. Interval/quinsy tonsillectomy candidacy if ≥1 prior PTA or recurrent tonsillitis meeting AAO-HNS modifying-factor criteria (AAO-HNS Tonsillectomy 2019; Rosi-Schumacher 2023 — quinsy and interval tonsillectomy equivalent outcomes). Counsel return precautions for re-accumulation, airway, and Lemierre.
    inputs: recurrent_peritonsillar_abscess_or_tonsillitis
    advance: follow-up + tonsillectomy-candidacy decision + return precautions documented