12-phase flow (12)

1. 1FRAME
   Frame the external-ear-canal infection across its full severity arc: uncomplicated diffuse AOE is a TOPICAL-ONLY disease (AAO-HNS strong rec AGAINST initial systemic antimicrobials — Rosenfeld 2014); the engine's parallel job is to detect the host/exam signal of NECROTIZING (malignant) OE — Pseudomonas skull-base osteomyelitis in the diabetic/immunocompromised/elderly — which flips management entirely. Distinguish FROM acute otitis media (middle ear) and FROM referred otalgia / EAC malignancy. Skull-base-osteomyelitis source control, sepsis, and glycemic emergencies are routed OUT by engine_id, not authored here.
   advance: OE scope confirmed; AOE-vs-necrotizing-OE dual frame established; not-this-engine concerns routed by engine_id
2. 2ENTRY
   Recognise the entry trigger — acute otalgia/otorrhea/canal-edema (likely diffuse AOE) vs pain-out-of-proportion + granulation (necrotizing-OE pivot) vs not-responding-at-48-72h (mandatory reassessment) vs at-risk host (diabetic/immunocompromised/elderly) vs cranial neuropathy (skull-base spread); capture pain severity and proportionality up front (the AAO-HNS strong-rec pain action).
   inputs: otalgia_severity_and_proportionality
   advance: entry trigger identified; pain assessed and analgesia recommended by severity
3. 3CONTEXT
   Build the host + substrate prior: canal exam (diffuse edema/discharge = AOE; localized pustule = furunculosis; granulation at bony–cartilaginous junction = necrotizing pivot); TM status (gates ototoxic-drop avoidance + separates from AOM); diabetes; immunocompromise; age; water/trauma/dermatitis substrate. This phase assigns the AOE-vs-otomycosis-vs-necrotizing-OE pretest probability.
   inputs: ear_canal_exam_edema_discharge_granulation, tympanic_membrane_status, diabetes, immunocompromise, age, water_exposure_or_canal_trauma
   actions: panel.glucose_a1c
   advance: host substrate + AOE/necrotizing pretest prior assigned
4. 4RED_FLAGS
   Necrotizing-OE + systemic red-flag screen: cranial-nerve exam (CN VII first → IX/X/XI/XII jugular foramen → VI petrous apex — skull-base spread, worst prognosis); fever/systemic toxicity; granulation tissue + pain out of proportion in a diabetic/immunocompromised host. Positive necrotizing screen → high-suspicion pathway + route to id.osteomyelitis.core.v1 for prolonged systemic therapy + ID co-management; qSOFA≥2/sepsis → route to id.sepsis.core.v1; isolated CN VII without ear disease → consider neuro.bells-palsy.core.v1 (but necrotizing OE must be excluded first in any at-risk host).
   inputs: cranial_nerve_examination, temperature
   actions: calc.qsofa, workup.bells_palsy
   advance: necrotizing-OE + sepsis + cranial-neuropathy red flags screened and routed by engine_id if positive
5. 5INITIAL_WORKUP
   Uncomplicated AOE needs NO labs/imaging — clinical diagnosis, topical therapy (AAO-HNS CPG 2014). When any necrotizing modifier is present: ESR + CRP baseline (the disease-activity/treatment-response markers — Loh 2013), glucose/HbA1c (quantify the dominant driver), CBC + inflammation panel, creatinine for systemic dosing. Aural toilet + microscopy at the same visit to clear debris and enable drop delivery.
   inputs: esr, crp, glucose_or_a1c
   actions: panel.cbc, panel.inflammation, panel.glucose_a1c
   advance: uncomplicated AOE → straight to TREATMENT; necrotizing modifier → baseline ESR/CRP/glucose sent + aural toilet done
6. 6BRANCHING_WORKUP
   Necrotizing-OE confirmation tree: canal/granulation-tissue culture (Pseudomonas vs MRSA vs fungal MOE — Roland & Stroman 2002; Sideris 2024) AND mandatory biopsy of granulation to exclude EAC squamous-cell carcinoma; CT temporal bone for bony erosion; Tc-99m bone scintigraphy when CT equivocal (Haleem 2025 — 56% positive in CT-negative); MRI/gallium SPECT for soft-tissue extent and serial treatment-response. Otomycosis branch: fungal elements on microscopy → topical antifungal + aural toilet (NOT antibacterial drops). Refractory/atypical "OE" → biopsy mandatory before extending therapy.
   inputs: ear_canal_culture, temporal_bone_ct_and_nuclear_or_mri
   actions: workup.cellulitis_necfasc, workup.lymphadenopathy
   advance: necrotizing OE confirmed/excluded + skull-base extent staged, OR otomycosis/EAC-malignancy alternative assigned and routed
7. 7DIFFERENTIAL
   Terminal differential with named pivots: uncomplicated diffuse AOE (diffuse canal edema + tragal tenderness + topical-responsive pivot) vs necrotizing/malignant OE (diabetic/immunocompromised host + granulation at bony–cartilaginous junction + pain out of proportion + ESR↑ pivot) vs otomycosis (itch-dominant + visible fungal hyphae/spores + topical-antibacterial failure pivot) vs furunculosis (localized pustule on a hair-bearing canal pivot) vs acute otitis media ± perforation (middle-ear pathology + bulging/perforated TM + NO canal-edema pivot — route ent.otitis-media.core.v1) vs EAC squamous-cell carcinoma / referred otalgia (refractory granulation + no inflammatory response + biopsy pivot) vs eczematous/contact dermatitis OE (chronic itch + dermatitis elsewhere pivot)
   advance: single best diagnosis selected; necrotizing OE explicitly excluded or confirmed; co-existence (AOE precipitating necrotizing OE in a diabetic) flagged
8. 8RISK_STRATIFICATION
   Stratify: uncomplicated AOE = low-risk outpatient. Necrotizing OE is high-risk by definition — layer prognostic modifiers: cranial-nerve involvement (CN VII and especially lower CN palsy → worse outcome), clival/contralateral/intracranial extension, poor glycemic control, multidrug-resistant Pseudomonas, persistently elevated ESR/CRP. qSOFA/NEWS2 for systemic-toxicity tier. Severe pain, immunocompromise, or any necrotizing modifier lowers the admission threshold.
   inputs: temperature, cranial_nerve_examination
   actions: calc.news2, calc.qsofa
   advance: AOE risk tier OR necrotizing-OE prognostic modifier overlay assigned
9. 9TREATMENT
   TWO-track treatment. (A) Uncomplicated diffuse AOE: topical ladder — fluoroquinolone-otic (ofloxacin/ciprofloxacin) ± dexamethasone for 7 d (AAO-HNS CPG 2014; Drehobl 2008 — ciprofloxacin ≥86% cure noninferior to neomycin/polymyxin; Chu JAMA 2022 — cipro+steroid faster pain resolution), acetic-acid drops as a low-cost option (Cochrane 2010 — inferior beyond week 1), aural toilet + wick when canal occluded, NON-OTOTOXIC preparation if TM non-intact/tube, analgesia by pain severity (strong rec), NO systemic antimicrobial (strong rec against). Otomycosis → topical antifungal + aural toilet. (B) Necrotizing OE: PROLONGED systemic anti-pseudomonal therapy — IV ceftazidime or piperacillin-tazobactam ± oral/IV ciprofloxacin (Loh 2013; Long 2020), aggressive glycemic control (route endo.dm2.core.v1), ENT + ID co-management, ESR/CRP-guided duration (often 6+ weeks), surgical debridement only for sequestra/abscess — source-control + prolonged-therapy ownership routed to id.osteomyelitis.core.v1.
   inputs: creatinine, tympanic_membrane_status
   advance: AOE → topical regimen + analgesia + aural-toilet/wick started, no systemic antibiotic; necrotizing OE → systemic anti-pseudomonal + glycemic control + ENT/ID co-management initiated and routed
10. 10DISPOSITION
    Uncomplicated AOE → outpatient with 48–72 h return-if-not-better safety net (Rosenfeld AAO-HNS CPG 2014). Necrotizing OE (suspected or confirmed) → admit for IV anti-pseudomonal therapy, imaging, ENT/ID; route to id.osteomyelitis.core.v1 for prolonged-therapy ownership. Systemic toxicity / qSOFA≥2 → admit + route id.sepsis.core.v1. EAC malignancy on biopsy → head-and-neck oncology referral. Document the necrotizing-OE exclusion explicitly in every at-risk host.
    inputs: temperature, cranial_nerve_examination
    advance: disposition documented; necrotizing OE either excluded with rationale or admitted+routed
11. 11MONITORING
    Uncomplicated AOE: clinical improvement expected by 48–72 h; persistence at 48–72 h mandates reassessment (confirm diagnosis, exclude necrotizing OE / otomycosis / EAC malignancy / non-ototoxic-drop need / non-adherence) NOT silent therapy extension (AAO-HNS CPG 2014 key-action statement). Necrotizing OE: serial ESR + CRP as the objective treatment-response markers gating antibiotic duration and step-down (Loh 2013 — correlate with disease activity); repeat MRI/nuclear imaging for persistent symptoms; surveillance for new cranial neuropathy or contralateral spread.
    inputs: esr, crp
    actions: panel.inflammation
    advance: AOE improving by 48–72 h OR reassessment triggered; necrotizing OE ESR/CRP trending down toward cessation criteria
12. 12FOLLOWUP
    AOE recurrence prevention: dry-ear precautions, treat the eczematous/contact-dermatitis substrate, acidifying/drying drops for recurrent swimmer's ear, avoid cotton-bud trauma, hearing-aid hygiene. Necrotizing OE: long-term ENT/ID surveillance for recurrence (relapse can occur months later — re-image and re-check ESR/CRP on any symptom return), sustained glycemic optimization (route endo.dm2.core.v1 — the dominant modifiable recurrence driver), and cranial-nerve rehabilitation follow-up where deficits persist.
    inputs: diabetes, water_exposure_or_canal_trauma
    advance: AOE prevention plan documented; necrotizing OE long-term ENT/ID + glycemic-optimization surveillance plan established and routed