12-phase flow (10)

1. 1FRAME
   Methamphetamine HTN crisis = α-adrenergic-driven vasoconstriction + tachycardia + dopaminergic psychosis + serotonergic hyperthermia, SUSTAINED 12-24 h (vs cocaine 1-2 h) due to ~10-12 h half-life. Pharmacology pivot: BENZODIAZEPINE FIRST for sympatholysis, often requiring sustained titration over 12-24 h (longer than cocaine); AVOID β-blocker monotherapy (unopposed alpha — Lange NEJM 1989 PMID 2522592 + AHA 2008 PMID 18391116 + AHA 2024 stimulant cardiotoxicity statement); AGGRESSIVE COOLING for hyperthermia >40°C (ice bath, evaporative, cold IV crystalloid). Route to parent engine for shared HTN-emergency arc; this dossier owns the meth-specific sustained pharmacology + meth-induced cardiomyopathy + SUD treatment.
   inputs: sbp, dbp, heart_rate, temperature, methamphetamine_exposure_history
   advance: meth/amphetamine etiology confirmed by history or UDS
2. 2ENTRY
   Recognize sustained meth toxidrome (HTN + tachy + diaphoresis + hyperthermia + agitation + dilated pupils + psychosis); ECG within 10 min if chest pain; benzo-first sympatholysis with anticipation of repeat dosing over 12-24 h; aggressive cooling if temp >40°C
   inputs: age, sbp, temperature, agitation_and_psychosis_assessment
   advance: IV access × 2 + cardiac monitor + benzo administered + cooling started if hyperthermic
3. 3CONTEXT
   Meth exposure timeline + dose + route + frequency (chronic daily user vs binge); coingestants (alcohol, opioids, fentanyl, cocaine — fentanyl-laced meth supply increasingly common); prior CV history + prior meth-related events; chronic meth use → cardiomyopathy risk; psychiatric comorbidities; housing/social context; HIV/HCV risk factors
   inputs: age
   advance: context complete
4. 4RED_FLAGS
   Hyperthermia >40°C → aggressive cooling + benzo + paralysis if refractory (highest mortality risk); concurrent STEMI/ACS → meth-associated MI pathway (PCI safe, AVOID β-blocker monotherapy); aortic dissection (meth raises risk similar to cocaine); ICH (meth + HTN + arteritis-like vasculopathy); rhabdomyolysis-AKI (often more severe than cocaine); acute meth-induced cardiomyopathy with cardiogenic shock; serotonin syndrome overlap if MDMA/cathinones with SSRI use; β-blocker exposure error (if patient already received metoprolol/esmolol/propranolol pre-recognition — anticipate paradoxical worsening + give phentolamine to reverse)
   inputs: sbp, temperature, chest_pain_assessment, agitation_and_psychosis_assessment
   actions: htn_emergency, cocaine_chest_pain
   advance: RED flags screened + life-threats addressed
5. 5INITIAL_WORKUP
   ECG q15 min × 1h if chest pain; serial troponin q3-6h × 2; UDS (amphetamine class); CMP + Mg + CK + lactate (rhabdo + perfusion); CXR (aortic disease, pulm edema); CT head if neuro deficit (meth ICH risk); CT angio chest if dissection concern; bedside echo for LV function (meth-induced cardiomyopathy + Takotsubo)
   inputs: ecg_12_lead, troponin, urine_drug_screen, creatinine, creatine_kinase, echo_lv_function
   actions: panel.cardiac, panel.renal
   advance: workup documented + ACS/dissection/ICH/cardiomyopathy ruled in/out
6. 6BRANCHING_WORKUP
   If STEMI → cath lab (meth-associated MI treated like standard ACS with β-blocker AVOIDED acutely); if dissection → CTA chest + emergent CT surgery + parent aortic-dissection HTN engine; if ICH → CT head + neuro pathway; if meth cardiomyopathy with shock → cardiogenic shock engine + standard MCS escalation; if serotonin syndrome features (MDMA + SSRI) → cyproheptadine + STOP serotonergic agents
   advance: syndrome-specific pathway activated
7. 7TREATMENT
   STEP 1: Benzodiazepine IV (lorazepam 1-2 mg or diazepam 5-10 mg IV q5-10 min, REDOSE for sustained ~12-24 h sympatholysis given meth half-life — anticipate cumulative doses higher than cocaine cases) — sympatholytic + reduces HTN + reduces tachy + treats agitation/seizure (AHA 2008 Class I PMID 18391116 + AHA 2024 stimulant update). STEP 2: If BP still elevated — nitroglycerin IV (5-200 mcg/min titrate) for vasodilation + coronary vasodilation. STEP 3: Phentolamine 1-5 mg IV q5-15 min — pure alpha-blocker reverses meth alpha-vasoconstriction + reverses coronary vasospasm (Boehrer Am J Med 1993 PMID 8390052). STEP 4: CCB acceptable — verapamil 5-10 mg IV or diltiazem (Negus Circulation 1994 — extends to meth). LABETALOL is debated (theoretically OK as mixed α/β but small β-effect may cause unopposed alpha) — AHA 2024 says reasonable as add-on AFTER alpha-blockade. AVOID pure β-blockers (metoprolol, esmolol, propranolol) acutely — Lange NEJM 1989. STEP 5 — AGGRESSIVE COOLING if temp >40°C: ice packs to groin/axilla, evaporative cooling (mist + fan), cold IV crystalloid 0.9 NS or LR (4°C 1-2 L bolus), goal core temp <38.5°C within 30 min (delay → multi-organ failure). STEP 6 — If hyperthermia refractory + paralysis indicated → rocuronium (AVOID succinylcholine if rhabdo + hyperK risk); consider dantrolene 1-2.5 mg/kg IV if NMS-like or serotonin-syndrome overlap. STEP 7 — IV fluids for rhabdo/AKI prevention (LR or 0.9 NS, target UOP >1-2 mL/kg/h; consider sodium bicarbonate-containing fluids if CK >5000 with goal urine pH >6.5).
   inputs: sbp, dbp, heart_rate, temperature
   advance: IV agent titrated to SBP <160; sympathetic features improving; agitation controlled; temp <38.5°C
8. 8DISPOSITION
   ICU for q15 min BP + telemetry minimum 24 h (meth half-life 12 h → expect sustained need for benzo + BP titration); repeat ECG q4h × 24 h; serial troponin × 2; observation 24-48 h minimum if cocaine-pathway extension; daily echo if meth cardiomyopathy
   advance: ICU bed assigned + 24-48h observation plan
9. 9MONITORING
   Continuous ECG + telemetry; q15-30 min BP; serial troponin q3-6h × 2; CK q6h if rhabdomyolysis; UOP target >1-2 mL/kg/h; mental status + agitation scale q1h; temp q15-30 min if hyperthermic
   inputs: sbp, heart_rate, temperature
   actions: panel.cardiac
   advance: BP at target + ACS ruled out + sympathetic features resolved + temp normalized + UDS clearing
10. 10FOLLOWUP
    Substance use disorder counseling + treatment — CONTINGENCY MANAGEMENT has strongest RCT evidence for meth use disorder (Connors Annu Rev Clin Psychol 2018 PMID 29494256); no FDA-approved MAT for meth (mirtazapine + naltrexone-bupropion combo modest benefit per Trivedi NEJM 2021 PMID 33497547 + Coffin JAMA Psychiatry 2020 PMID 32049330); cardiology follow-up if MI/Takotsubo/cardiomyopathy occurred; ECHO at 3-6 months to assess for meth cardiomyopathy reversibility with abstinence (Schürer JACC 2017 — partial reversibility documented); BP regimen if persistent HTN; opioid agonist therapy if fentanyl-laced supply suspected; harm reduction; HIV/HCV screening; PrEP discussion if applicable
    advance: SUD treatment booked (contingency management + behavioral therapy) + cardiology follow-up + BP regimen if needed + harm reduction + repeat echo at 3-6 mo if cardiomyopathy