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For further information, see CMDT Part 38-09: Poisoning or Overdose-Related Hyperthermia

Key Features

  • A rapidly life-threatening complication

  • May be due to poisoning by

    • Amphetamines and other synthetic stimulants (cathinones, piperazines)

    • Atropine and other anticholinergic drugs

    • Cocaine

    • Salicylates

    • Strychnine

    • Tricyclic antidepressants

  • Overdose of serotonin reuptake inhibitors (eg, fluoxetine, paroxetine) alone or combined with monoamine oxidase inhibitor may cause agitation, hyperactivity, hyperthermia (serotonin syndrome)

  • Antipsychotic agents can cause rigidity and hyperthermia (neuroleptic malignant syndrome)

  • Malignant hyperthermia is associated with general anesthetic agents (rare)

Clinical Findings

  • Severe hyperthermia (temperature > 40–41°C) can rapidly cause brain damage and multiorgan failure, including

    • Rhabdomyolysis

    • Acute kidney injury

    • Coagulopathy


  • Remove clothing

  • Spray skin with tepid water

  • High-volume fanning of the patient

  • Alternatively, the patient can be placed in an ice water bath (not simply applying ice to selected surfaces)

  • Induce neuromuscular paralysis with a nondepolarizing neuromuscular blocker (eg, rocuronium, vecuronium)

    • If rectal temperature not normal in 30–40 min

    • If there is significant muscle rigidity or hyperactivity

  • Once paralyzed, patient must be intubated, mechanically ventilated, and sedated

  • Once the patient is paralyzed, the absence of visible muscular convulsive movements may give the false impression that brain seizure activity has ceased; bedside electroencephalography may be useful in recognizing continued nonconvulsive seizures

  • Dantrolene, 2–5 mg/kg intravenously, may be effective for muscle rigidity unresponsive to neuromuscular blockade (ie, malignant hyperthermia)

  • Bromocriptine, 2.5–7.5 mg daily orally, for neuroleptic malignant syndrome

  • Cyproheptadine, 4 mg every hour for 3–4 doses orally, or chlorpromazine, 25 mg intravenously or 50 mg intramuscularly, for serotonin syndrome

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