12-phase flow (12)

1. 1FRAME
   Frame the encounter as a TWO-CHANNEL problem: (A) positively diagnose definite-vs-probable Ménière against the Bárány/AAO-HNS criteria, anchored on the AUDIOGRAM, and run the stepped management ladder incl. the Tumarkin drop-attack safety issue; (B) robustly distinguish vestibular migraine (commonest mimic, often comorbid), BPPV, vestibular neuritis, posterior-circulation TIA/stroke, SSNHL, and autoimmune inner-ear disease. Definitive stroke/BPPV/neuritis/migraine/SSNHL/falls management is routed OUT by engine_id, not re-authored.
   advance: two-channel scope confirmed; out-of-scope definitive management flagged for engine_id routing
2. 2ENTRY
   Apply the duration pivot at the door: spontaneous episodic vertigo 20 min-12 h with fluctuating unilateral cochlear symptoms = the Ménière channel; seconds-positional → BPPV channel; single sustained AVS over days → vestibular-neuritis channel; minutes-days + migraine features → vestibular-migraine channel. Capture spell duration first because it reroutes the entire work-up (Lopez-Escamez J Vestib Res 2015 Bárány criteria).
   inputs: vertigo_spell_duration_20min_to_12h
   actions: workup.vertigo
   advance: spell-duration / spontaneity category assigned and the Ménière-vs-mimic channel selected
3. 3CONTEXT
   Build the pre-test differential: spontaneous (not obligately positional) trigger; fluctuating LOW/MID-frequency SNHL; unilateral tinnitus + aural fullness; migraine history (vestibular migraine — commonest mimic, often comorbid); vascular risk factors (posterior-circulation TIA prior for recurrent spells); prior SSNHL (delayed endolymphatic hydrops). This phase sets the Bayesian prior before audiometry.
   inputs: spontaneous_vs_positional_trigger, fluctuating_low_mid_frequency_hearing_loss, tinnitus_and_aural_fullness_affected_ear, migraine_history_photophobia_aura, vascular_risk_factors, prior_sudden_snhl_event
   actions: workup.vertigo
   advance: Ménière-vs-VM-vs-BPPV-vs-neuritis-vs-TIA prior assigned from triggers/duration/auditory/vascular profile
4. 4RED_FLAGS
   Screen the can't-miss exits: (1) the 4 D's / severe gait-truncal ataxia / focal signs during or between spells, or high vascular risk with recurrent audiovestibular spells → posterior-circulation TIA/AICA-territory stroke → route OUT to neuro.posterior-circulation-stroke.core.v1; (2) a SUDDEN (≤72 h) severe SNHL component (esp. first event) → SSNHL (time-critical steroid window) → route OUT to ent.sudden-sensorineural-hearing-loss.core.v1. These are recognised here and NOT managed here.
   inputs: central_neuro_4Ds_gait_during_or_between_spells, sudden_severe_unilateral_hearing_loss_component
   actions: calc.abcd2, workup.acute_stroke, workup.acute_headache
   advance: central + sudden-SNHL red flags screened and routed OUT by engine_id if positive
5. 5INITIAL_WORKUP
   Obtain PURE-TONE AUDIOMETRY — definite MD REQUIRES audiometrically documented low-to-mid-frequency SNHL in the affected ear on at least one occasion (the objective anchor). Tympanometry + speech audiometry; document the fluctuation pattern across visits. Routine MRI/IAC imaging is NOT required to diagnose MD but IS indicated to exclude retrocochlear pathology (vestibular schwannoma) when asymmetry/atypia is present (AAO-HNS CPG Basura 2020 — against routine imaging when criteria met, for imaging when atypical).
   inputs: pure_tone_audiometry_documentation
   actions: workup.vertigo
   advance: audiogram obtained + low/mid SNHL documented (definite) OR criteria incomplete (probable) OR retrocochlear imaging triggered
6. 6BRANCHING_WORKUP
   Classify definite vs probable MD (Bárány/AAO-HNS). If atypical (asymmetric/rapidly progressive, bilateral, systemic features) → MRI IAC to exclude vestibular schwannoma; autoimmune work-up if bilateral rapidly progressive steroid-responsive (AIED); ECochG/vestibular testing optional adjuncts (not required). If migraine features dominate without documented SNHL → reframe toward vestibular migraine and route to neuro.vestibular-migraine.core.v1. If positional component emerges (secondary BPPV can co-exist) → ent.bppv.core.v1 for the canal-positive component.
   actions: workup.vertigo, panel.inflammation
   advance: definite-vs-probable classified; retrocochlear/autoimmune mimic excluded or routed; comorbid VM/BPPV flagged
7. 7DIFFERENTIAL
   Terminal vestibular differential with named pivots: Ménière (spontaneous 20 min-12 h spells + DOCUMENTED fluctuating low/mid SNHL + tinnitus/fullness — audiogram pivot) vs vestibular migraine (migraine features, often NO documented SNHL, frequently comorbid — migraine-criteria pivot, route to neuro.vestibular-migraine.core.v1) vs BPPV (seconds, obligate positional trigger, no cochlear symptoms — Dix-Hallpike pivot, route to ent.bppv.core.v1) vs vestibular neuritis (single sustained AVS days, no cochlear symptoms — monophasic-course pivot, route to ent.vestibular-neuritis.core.v1) vs posterior-circulation TIA/stroke (vascular risk + central signs — HINTS/4Ds pivot, route to neuro.posterior-circulation-stroke.core.v1) vs SSNHL (sudden severe SNHL ± vertigo — time-course pivot, route to ent.sudden-sensorineural-hearing-loss.core.v1) vs autoimmune inner-ear disease (bilateral rapidly progressive steroid-responsive — bilaterality+steroid-response pivot).
   inputs: autoimmune_features_bilateral_rapidly_progressive
   actions: workup.vertigo
   advance: single best diagnosis (definite/probable MD or a mimic) selected; comorbid VM/BPPV flagged; out-of-scope diagnoses routed by engine_id
8. 8RISK_STRATIFICATION
   Stratify by attack burden + the Tumarkin drop-attack SAFETY axis + functional/fall-injury risk. Tumarkin otolithic crisis (sudden unprovoked falls, no LOC) is the highest-acuity feature — accelerates the ablative/surgical decision and triggers a falls-safety pathway. Layer hearing status (serviceable vs non-serviceable), bilaterality, frailty, anticoagulation, driving/occupational exposure as management modifiers.
   inputs: tumarkin_drop_attacks, vascular_risk_factors
   actions: calc.clinical_frailty_scale, calc.abcd2, calc.news2, workup.falls
   advance: attack burden + Tumarkin/fall-injury risk + hearing/bilaterality modifiers assigned
9. 9TREATMENT
   STEPPED management ladder (AAO-HNS CPG Basura 2020). Acute attack: short-course antiemetic / vestibular suppressant + reassurance (symptomatic only). Maintenance ladder: (1) lifestyle + low-salt diet ± diuretic ± betahistine (region-dependent; BEMED-negative — set realistic expectations) — low-quality evidence, low-harm first tier; (2) intratympanic CORTICOSTEROID (non-ablative, hearing-sparing — Patel Lancet 2016 non-inferior to gentamicin); (3) intratympanic GENTAMICIN (ABLATIVE — vestibulotoxic, HEARING-RISK guardrail: contraindicated if serviceable hearing must be preserved or only-hearing-ear / bilateral disease); (4) endolymphatic sac surgery / vestibular neurectomy (hearing-preserving) / labyrinthectomy (hearing-destructive) for intractable disease. Vestibular rehabilitation for chronic imbalance/compensation. Bilateral disease → hearing-preservation strategy, AVOID bilateral ablation. Pregnancy → low-salt + non-pharm ± IT steroid, avoid routine diuretic/acetazolamide.
   inputs: bilateral_or_contralateral_progression, hearing_status_affected_and_better_ear, pregnancy
   advance: appropriate ladder step selected with the ablation/hearing guardrail applied; acute-attack symptomatic plan set; bilateral/pregnancy modifiers honoured
10. 10DISPOSITION
    Most MD is OUTPATIENT (audiology + neurotology longitudinal care). Admit/observe for: intractable vomiting with dehydration, a severe disabling attack precluding safe discharge, recurrent injurious Tumarkin drop attacks, or a red-flag mimic requiring the stroke/SSNHL pathway (route OUT). Intractable disease failing the medical ladder → neurotology referral for IT gentamicin / surgical decision.
    inputs: tumarkin_drop_attacks, central_neuro_4Ds_gait_during_or_between_spells
    actions: workup.falls
    advance: disposition documented; red-flag mimics routed OUT; intractable/Tumarkin cases escalated to neurotology
11. 11MONITORING
    CHRONIC stepped-care monitoring: SERIAL AUDIOMETRY (track low/mid SNHL fluctuation and stepwise progression — hearing loss accrues mainly in the first 5-10 y, ~50-60 dB; Huppert 2010); vertigo-attack diary (frequency/severity drives ladder step-up/step-down); after IT GENTAMICIN, monitor hearing closely (ablation hearing-loss risk) and balance compensation; after IT steroid, reassess attack control to decide repeat vs escalate; diuretic course → electrolytes/renal monitoring; surveil for CONTRALATERAL progression to bilateral disease (changes the whole hearing-preservation strategy). Counsel that attack frequency tends to burn out over years even though hearing may decline.
    inputs: pure_tone_audiometry_documentation, bilateral_or_contralateral_progression
    actions: workup.vertigo, panel.cmp
    advance: serial audiogram + attack-diary trend reviewed; post-intervention hearing/electrolyte monitoring done; bilaterality surveillance documented
12. 12FOLLOWUP
    CHRONIC longitudinal arc (the core differentiator): structured neurotology + audiology follow-up with the stepped ladder revisited at each interval; vestibular rehabilitation for residual imbalance; hearing rehabilitation (hearing aid; cochlear implant if profound and the contralateral ear is also affected); psychological support (MD has high anxiety/depression burden); DRIVING and OCCUPATIONAL safety counselling (unpredictable vertigo / Tumarkin — fitness-to-drive reporting per jurisdiction); bilaterality surveillance and hearing-preservation planning; route elderly recurrent drop-attack patients to geriatrics.falls.core.v1 for the multifactorial falls programme.
    inputs: driving_occupational_safety_exposure, bilateral_or_contralateral_progression
    actions: workup.falls
    advance: longitudinal stepped-care + vestibular/hearing rehab + safety-counselling + bilaterality-surveillance plan documented; falls referral made if criteria met