Hyperthermia

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

• 2,4-dinitrophenol

• 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)

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

• Rhabdomyolysis

• Advanced chronic kidney disease

• 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