Clinical Commander

All dossiers
anesthesia.malignant-hyperthermia.core.v1

Malignant Hyperthermia Crisis

critical_careacuteadultpediatricacuteinpatient
Start encounter →Print handoutPRODUCTION

Lane-C anesthesia campaign — must-not-miss perioperative crisis. Dantrolene (RxCUI 3105) verified live via RxNav; Ryanodex (concentrated) is the preferred formulation but RxNorm name remains "dantrolene". Sodium bicarbonate 36676, insulin regular 253182, dextrose/glucose 4850, mannitol 6628, furosemide 4603, amiodarone 703 all RxNav-verified. AVOID Ca-channel blockers with dantrolene. MHAUS hotline 1-800-644-9737 documented in playbooks. PMIDs 20081135 (Larach), 28902675 (Riazi), 9523799 (Allen-Larach CHCT) live-verified via PubMed MCP.

Entry points (5)

  • symptom
    Unexplained rising EtCO2 despite increased minute ventilation (MHAUS 2023)
    unexplained_hypercarbia_intraop
  • symptom
    Masseter muscle rigidity / generalized rigidity after succinylcholine (MHAUS 2023)
    masseter_muscle_rigidity
  • vital_abnormality
    Rapid rise in core temperature (>=1-2C in 5 min, late finding) (MHAUS 2023)
    rapid_temperature_rise
  • history
    Prior MH event, known RYR1/CACNA1S variant, or first-degree relative susceptible (Riazi 2018)
    prior_mh_or_ryr1_cacna1s
  • lab_abnormality
    Mixed respiratory + metabolic acidosis intraoperatively (Larach 2010)
    mixed_acidosis_intraop

Required inputs (13)

  • agerequired
    demographic • used at CONTEXT
    Pediatric dantrolene dosing identical mg/kg; total cumulative dose differs (MHAUS 2023)
  • weight_kgrequired
    demographic • used at TREATMENT
    Dantrolene initial 2.5 mg/kg IV bolus; mg/kg-based throughout (MHAUS 2023)
  • core_temperaturerequired
    vital • used at RED_FLAGS
    Temperature trajectory drives severity grading and cooling threshold (Larach 2010)
  • etco2required
    vital • used at RED_FLAGS
    Hypercarbia is earliest sign; minute-ventilation-adjusted EtCO2 trend critical (MHAUS 2023)
  • hrrequired
    vital • used at CONTEXT
    Sinus tachycardia / dysrhythmia track hypermetabolism (Larach 2010)
  • abgrequired
    lab • used at INITIAL_WORKUP
    Mixed respiratory + metabolic acidosis confirms hypermetabolism (MHAUS 2023)
  • potassiumrequired
    lab • used at INITIAL_WORKUP
    Hyperkalemia from rhabdomyolysis drives arrhythmia + dialysis decision (MHAUS 2023)
  • ckrequired
    lab • used at INITIAL_WORKUP
    CK peak documents rhabdomyolysis severity (Larach 2010)
  • myoglobin_urine
    lab • used at INITIAL_WORKUP
    Myoglobinuria drives renal protection / mannitol / bicarb plan (MHAUS 2023)
  • coag_panel
    lab • used at INITIAL_WORKUP
    DIC is a late complication; screen at presentation and serial (MHAUS 2023)
  • volatile_anesthetic_exposurerequired
    history • used at RED_FLAGS
    Sevoflurane / isoflurane / desflurane / halothane are triggers — must STOP (MHAUS 2023)
  • succinylcholine_exposurerequired
    history • used at RED_FLAGS
    Succinylcholine is a trigger — masseter spasm is hallmark; document timing (MHAUS 2023)
  • mh_family_history
    history • used at CONTEXT
    Family RYR1/CACNA1S history changes preop trigger-free anesthetic plan (Riazi 2018)

12-phase flow (12)

  1. 1FRAME
    Confirm perioperative MH crisis scope — pharmacogenetic hypermetabolic syndrome after halogenated volatile or succinylcholine in genetically susceptible patient (MHAUS 2023)
    inputs: age, weight_kg
    advance: volatile or succinylcholine exposure with hypermetabolic signs
  2. 2ENTRY
    Recognize early hypercarbia + tachycardia + masseter rigidity + acidosis pattern (do NOT wait for temperature spike) (MHAUS 2023)
    inputs: etco2, hr
    advance: any entry trigger present
  3. 3CONTEXT
    Anesthetic record review (which volatile, succ given, dose, timing), MH family history, prior anesthetics, current weight (MHAUS 2023)
    inputs: volatile_anesthetic_exposure, succinylcholine_exposure, mh_family_history, weight_kg
    advance: trigger inventory complete
  4. 4RED_FLAGS
    Call for HELP + MH cart + dantrolene; STOP all volatiles; switch to TIVA; hyperventilate 100% O2 at >=10 L/min via clean circuit; call MHAUS Hotline 1-800-644-9737 (MHAUS 2023)
    inputs: core_temperature, etco2, volatile_anesthetic_exposure
    advance: triggers discontinued AND dantrolene en route
  5. 5INITIAL_WORKUP
    ABG, BMP (potassium urgently), CK, lactate, coags, urine myoglobin; continuous core temperature + EtCO2; arterial line + foley (MHAUS 2023)
    inputs: abg, potassium, ck
    actions: panel.abg, panel.renal, panel.cbc, panel.coag
    advance: critical labs drawn and dantrolene started
  6. 6BRANCHING_WORKUP
    Echo if persistent hemodynamic instability; head CT if AMS post-resuscitation; urine myoglobin trend; serial CK q6h x 24-36h (MHAUS 2023)
    inputs: myoglobin_urine
    advance: complications characterized
  7. 7DIFFERENTIAL
    Distinguish MH from thyroid storm, pheochromocytoma, neuroleptic malignant syndrome, sepsis, serotonin syndrome, iatrogenic overheating, light anesthesia, inadequate ventilation (MHAUS 2023)
    advance: MH confirmed or excluded
  8. 8RISK_STRATIFICATION
    Larach Clinical Grading Scale (very likely vs almost certain MH); severity index drives ICU stay length + dantrolene duration (Larach 2010)
    inputs: core_temperature, potassium, ck
    advance: CGS rank assigned
  9. 9TREATMENT
    Dantrolene 2.5 mg/kg IV bolus, repeat q5-10 min titrated to signs (no fixed max; expect 10 mg/kg cumulative, exceed if needed); cooling to 38C then stop; treat hyperkalemia (CaCl + insulin/dextrose + bicarb); manage dysrhythmia with amiodarone (AVOID Ca-channel blockers — interact with dantrolene); mannitol/furosemide + bicarb for myoglobinuria (MHAUS 2023)
    inputs: weight_kg, potassium, core_temperature
    advance: EtCO2 falling, HR slowing, temperature trending down, acidosis correcting
  10. 10DISPOSITION
    ICU x >=24h post-crisis on dantrolene 1 mg/kg IV q4-6h (or infusion 0.25 mg/kg/h) for at least 24h after stability; recrudescence in up to 25% (MHAUS 2023)
    inputs: core_temperature, etco2
    advance: ICU bed + dantrolene maintenance plan locked
  11. 11MONITORING
    Continuous core temp, EtCO2, ABG q1-2h, BMP + CK q6h, urine output >=2 mL/kg/h, urine color (myoglobin), coags (DIC screen) (MHAUS 2023)
    inputs: abg, ck, myoglobin_urine
    advance: CK trending down, urine clear, no recrudescence x 24h
  12. 12FOLLOWUP
    Referral to MH Diagnostic Center (CHCT / IVCT or RYR1/CACNA1S sequencing); MedicAlert bracelet; family counseling; future anesthetic plan (trigger-free TIVA); MHAUS registry case report (MHAUS 2023, Riazi 2018)
    advance: referral + family counseling documented