Drug-Induced Hyperthermia - Dr. Kerns

Mechanisms of hyperthermia

• Hurt the hypothalamus or mess with NT
• Increased muscle activity
• Vasoconstriction
• Uncoupling cellular respiration

Malignant Hyperthermia
   - Rare
   - Increased peripheral muscle activity due to ryanodine receptor issues - genetic component
   - Only seen with anesthesia - halothane, succinylcholine
   - Fast onset from exposure, severe and short lived - hyperK, muscle rigidity, autonomic instability,
   - increased CO2 on capnography


Neuroleptic Malignant Syndrome
   - Due to altered DA transmission - seen with typical antipysch meds, lithium, environmental (heat)
   - Subacute, severe, lasts day-weeks
   - Lead pipe rigidity, autonomic instability, AMS


Parkinsons Disease
   - abrupt withdraw of DA agonist therapy can cause hyperpyrexia


Cocaine/ Stimulants
  - Hypothalamic stimulation, vasoconstriction, increased muscle activity
  - Fast onset, short duration, severe hyperthermia


Serotonin Syndrome
   - Increased central 5HT activity
   - More common in drug drug interactions - SSRI/SSRI or SSRI & other serotonin agonists - TCA,
     demerol, linezolid, MAOI, tramadol, dextromethrophan (MAOI activity)
   - Subacute, moderate severity
   - AMS, muscle rigidity (LE>>UE), hyperreflexia & rigidity, autonomic instability

   - NBOME - designer drugs - increased serotonin activity


OTHERS:
Anticholinergic
   - increased muscarnic blockade
Salicylate toxicity
   - uncouples cellular respiration
Baclofen withdraw


Complications from hyperthermia

  - Resp, PE, rhabdo, hepatic failure, hyperK


Treatments

- DC offending agents or restart withdrawn med
- Physical cooling
- Sedation - benzos, non depolarizing blockade

 - Secondary Treatments
      > Cyproheptadine - serotonin antagonist (for 5HT syndrome) - PO only
      > Dantrolene - for malignant hyperthermia - first line agent
      > Limited evidence for NMS - dantrolene has been tried - don't use as monotherapy
      > Dopamine agonist - bromocriptine, amantadine - dont use as monotherapy (long time to start acting)

     > ECT - unknown mechanism

54000 or 800-222-1222 - poison control

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