Lesson 7

Drug-Induced Hyperthermic Syndromes

  • Not all drug-induced hyperthermia is malignant hyperthermia.

    • Other causes include:
    • Neuroleptic malignant syndrome: Caused by dopamine depletion.
    • Serotonin syndrome: Caused by excess 5-HT activity.
    • Anticholinergic poisoning: Caused by excess ACh blockade.

  • Methylene blue: MAO-A inhibiting properties; increases serotonin syndrome risk with other serotonergic drugs.

  • Pharmacologic treatments:

    • Neuroleptic malignant syndrome: Bromocriptine, Dantrolene.
    • Serotonin syndrome: Cyproheptadine.
    • Anticholinergic poisoning: Physostigmine.

Hyperthermic Syndrome Characteristics

  • Miscellaneous Causes and Treatments:

    • Malignant Hyperthermia: Time to onset within minutes.

    • Causes: Halogenated anesthetics, Succinylcholine.

    • Key Features: Hypercarbia, Tachycardia, Myoglobinuria, Acidosis, Muscle rigidity (YES).

    • Treatment: Dantrolene, Supportive care.

    • Sympathomimetic Syndrome: Up to 30 minutes onset.

    • Causes: Amphetamines, Cocaine.

    • Key Features: Agitation; Muscle rigidity (NO).

    • Treatment: Supportive care, Vasodilators (e.g. Labetalol, Magnesium).

    • Tricyclic Antidepressant Overdose: Up to 6 hours onset.

    • Key Features: Hallucinations, Arrhythmias, Muscle rigidity (NO).

    • Treatment: Supportive care, Serum alkalization.

    • Serotonin Syndrome: Up to 12 hours onset.

    • Causes: SSRIs, SNRIs, MAOIs, MDMA.

    • Key Features: Akathisia, Mydriasis, Tremor, Altered mental status, Clonus, Muscle rigidity (YES).

    • Treatment: Cyproheptadine (oral 5-HT2A antagonist), Chlorpromazine (IV), Supportive care.

    • Anticholinergic Syndrome: Up to 12 hours onset.

    • Key Features: Red, hot, dry skin, Mydriasis, Delirium, Muscle rigidity (NO).

    • Treatment: Physostigmine, Supportive care.

    • Neuroleptic Malignant Syndrome: Up to 24-72 hours onset.

    • Key Features: Bradykinesia, Decreased LOC/coma, Rhabdomyolysis, Myoglobinuria, Acidosis, Muscle rigidity (YES).

    • Treatment: Bromocriptine, Dantrolene, Supportive care, ECT.