12-phase flow (12)

1. 1FRAME
   Set the acute drug-induced EPS frame: acute dystonia (incl. LARYNGEAL airway emergency) vs acute akathisia vs drug-induced parkinsonism × causative agent (typical/atypical AP / metoclopramide / prochlorperazine / promethazine / droperidol) × pediatric/young-adult (dystonia risk) vs adult vs elderly (parkinsonism risk) × first-exposure vs dose-escalation — and explicitly NOT NMS / serotonin syndrome / tardive dyskinesia (Pierre Drug Saf 2005 PMID 16180939; van Harten BMJ 1999 PMID 10463905)
   inputs: age
   advance: Phenotype + agent + population + exposure-window hypothesis assigned; NMS/serotonin-syndrome explicitly considered
2. 2ENTRY
   Trigger from acute abnormal posturing / oculogyric crisis after a dopamine-antagonist, stridor or dysphonia (laryngeal — life-threatening), inner-restlessness/pacing (akathisia), or bradykinesia/rigidity/tremor (parkinsonism); ED-antiemetic context is a common under-recognized entry (van Harten BMJ 1999 PMID 10463905; Drotts Ann Emerg Med 1999 PMID 10499951)
   inputs: eps_phenotype
   advance: Acute-EPS pathway activated + dopamine-antagonist exposure documented + laryngeal involvement screened
3. 3CONTEXT
   Offending agent + class + potency + dose + route + exposure timing (first-exposure / dose-escalation / depot / IV-bolus), age, prior acute dystonia + risk factors, concurrent serotonergic + anticholinergic load, full medication reconciliation (occult antiemetics) (Pierre Drug Saf 2005 PMID 16180939; van Harten BMJ 1999 PMID 10463905)
   inputs: offending_dopamine_antagonist, age, prior_eps_or_risk_factors, concurrent_serotonergic_or_anticholinergic_load
   advance: Causative-agent + population + risk-modifier data captured
4. 4RED_FLAGS
   LARYNGEAL DYSTONIA (stridor / dysphonia / dyspnea / throat-tightening) = airway emergency → immediate IV anticholinergic + airway readiness + escalate. Hyperthermia + autonomic instability + altered mental status + lead-pipe rigidity → STOP, reframe to NMS (cross-ref psych.neuroleptic-malignant-syndrome.v1). Clonus + hyperreflexia + serotonergic agent → serotonin syndrome (cross-ref psych.serotonin-syndrome.v1) (Pierre Drug Saf 2005 PMID 16180939; van Harten BMJ 1999 PMID 10463905)
   inputs: laryngeal_airway_involvement, temp_hr_bp_for_nms_exclusion
   actions: workup.hyperthermic_toxidromes
   advance: Laryngeal/airway involvement assessed + treated, and NMS / serotonin-syndrome explicitly excluded or cross-routed
5. 5INITIAL_WORKUP
   Largely CLINICAL diagnosis — full medication reconciliation (identify occult antiemetics / depot AP), CK (to exclude NMS — rendered inline), ECG/QTc if offending or substituted agent is QT-prolonging or propranolol planned; do NOT delay IV/IM anticholinergic reversal of acute dystonia for labs (van Harten BMJ 1999 PMID 10463905; Pierre Drug Saf 2005 PMID 16180939)
   inputs: medication_reconciliation_full, ck_to_exclude_nms, ecg_qtc_if_droperidol_context
   actions: panel.cbc, panel.renal
   advance: Offending agent confirmed by reconciliation; NMS-exclusion CK obtained where indicated (not gating dystonia reversal)
6. 6BRANCHING_WORKUP
   Phenotype-directed: acute dystonia → no further imaging if classic posturing reverses with anticholinergic (a diagnostic-therapeutic trial); atypical/persistent → neuro evaluation (exclude seizure / focal lesion / tetanus / primary dystonia); akathisia → exclude restless-legs / anxiety / psychotic agitation; parkinsonism → assess for unmasked idiopathic Parkinson disease if asymmetric or persists > 3-6 months off agent (Pierre Drug Saf 2005 PMID 16180939; Seitz Drugs Aging 2009)
   inputs: eps_phenotype
   actions: workup.encephalopathy
   advance: Phenotype-specific mimics excluded; therapeutic-trial response to anticholinergic documented for dystonia
7. 7DIFFERENTIAL
   Acute dystonia (clear sensorium + sustained focal/segmental posturing, rapid anticholinergic reversal — LR+ high) vs akathisia (inner restlessness + pacing, normal tone) vs drug-induced parkinsonism (bradykinesia + rigidity + tremor, insidious) — all distinguished from NMS (fever + autonomic instability + diffuse lead-pipe rigidity + ↑↑CK + AMS) and serotonin syndrome (clonus + hyperreflexia + serotonergic agent + hyperthermia); akathisia screens for suicidality/aggression (Pierre Drug Saf 2005 PMID 16180939; Barnes Br J Psychiatry 1989 PMID 2574607)
   inputs: eps_phenotype, mental_status_and_rigidity_character, suicidality_aggression_with_akathisia
   advance: Working phenotype attribution assigned + NMS / serotonin-syndrome cross-route triggers evaluated
8. 8RISK_STRATIFICATION
   Laryngeal dystonia → life-threatening (airway). Generalized dystonia / oculogyric crisis / severe akathisia with suicidality → severe. Focal dystonia / moderate akathisia / functional parkinsonism → moderate. Mild parkinsonism / mild akathisia → mild. Severity + phenotype + airway involvement drive setting + agent + monitoring; AIMS / Barnes-akathisia scored inline (Barnes Br J Psychiatry 1989 PMID 2574607; Guy AIMS ECDEU 1976)
   inputs: eps_phenotype, laryngeal_airway_involvement
   actions: calc.ckd_epi_2021
   advance: Severity band + airway risk + treatment tier + monitoring level + disposition documented
9. 9TREATMENT
   Acute dystonia → IV/IM anticholinergic (benztropine 1-2 mg IV/IM OR diphenhydramine 25-50 mg IV/IM; repeat in 20-30 min if no response; benzodiazepine [lorazepam 1-2 mg] adjunct for refractory) + AIRWAY MANAGEMENT and escalate if laryngeal. Offending agent → stop/reduce/switch to lower-EPS-risk agent + oral anticholinergic 24-72 h to prevent recurrence. Akathisia → reduce/switch agent + propranolol 10-20 mg TID first-line + benzodiazepine; mirtazapine 15 mg alternative; screen suicidality. Parkinsonism → dose reduction/switch + anticholinergic (caution elderly) OR amantadine 100 mg BID (Pierre Drug Saf 2005 PMID 16180939; van Harten BMJ 1999 PMID 10463905; Lima Cochrane PMID 15495018 / 11034738; Poyurovsky Br J Psychiatry 2001 PMID 11581110)
   inputs: eps_phenotype, offending_dopamine_antagonist
   advance: Phenotype-directed reversal/treatment given + offending agent managed + airway secured if laryngeal + recurrence-prevention plan set
10. 10DISPOSITION
    Laryngeal dystonia → ED resuscitation / observation with airway readiness until fully reversed. Generalized acute dystonia → observe until reversed + recurrence-prevention anticholinergic + offending-agent plan, then discharge with return precautions. Akathisia with suicidality → cross-route psych.suicidality.ed.core.v1. Drug-induced parkinsonism → outpatient with agent change + monitored resolution; admit if reframed to NMS (cross-ref psych.neuroleptic-malignant-syndrome.v1) (Pierre Drug Saf 2005 PMID 16180939; Barnes Br J Psychiatry 1989 PMID 2574607)
    actions: workup.suicide_risk
    advance: Level of care set + recurrence-prevention plan documented + cross-route engaged as applicable
11. 11MONITORING
    Acute dystonia — observe ≥ 4-6 h for response + rebound after IV anticholinergic half-life wanes (recurrence common — continue oral anticholinergic 24-72 h, longer if offending agent continued). Laryngeal — continuous SpO2 + airway watch until fully resolved. Akathisia — serial Barnes scale + suicidality re-screen. Parkinsonism — serial exam over weeks for resolution after agent change; persistence > 3-6 months suggests unmasked idiopathic PD. Watch for emergent NMS (fever/rigidity/↑CK) on any continued antipsychotic (Pierre Drug Saf 2005 PMID 16180939; Barnes Br J Psychiatry 1989 PMID 2574607)
    advance: Symptom resolved or on documented recurrence-prevention + monitoring schedule; airway cleared if laryngeal
12. 12FOLLOWUP
    Document the offending agent as an adverse drug reaction / allergy-list entry; communicate the EPS-risk to prescribers; choose a lower-EPS-risk agent for ongoing psychiatric need (route disease-specific engine); akathisia → psychiatric follow-up + adherence support; parkinsonism → confirm resolution off agent vs unmasked idiopathic PD (neurology); patient education on early dystonia recognition + return precautions (Pierre Drug Saf 2005 PMID 16180939; Seitz Drugs Aging 2009)
    advance: Offending agent documented as ADR + lower-EPS-risk plan arranged + phenotype-directed follow-up set + cross-route dossiers engaged