The more well known causes of toxin-induced hyperthermia include sympathomimetics and anticholinergics. In addition, neuroleptic malignant syndrome, serotonin syndrome, and malignant hyperthermia are high on the differential.
Several other xenobiotics can cause hyperthermia in overdose as well:
Salicylates and dinitrophenol cause hyperthermia by uncoupling oxidative phosphorylation.
Thyroid medications cause hyperthermia via thyroid hormone's thermogenic effect and psychomotor agitation. Hyperthermia can be extreme (>106°F, >41°C).
Caffeine/theophylline, isoniazid, and strychnine cause hyperthermia through refractory seizures and muscle contraction. Highest temp recorded with strychnine is (109.4°F, 43°C).
In general, benzodiazepines should be considered first-line therapy, followed by barbiturates, propofol, or other sedative hypnotics. Phenytoin rarely has a role in the management of toxin-induced seizures. Extrenal cooling measures are also warranted. Specifically for isoniazid, pyridoxine should be administered immediately with a benzodiazepine.
References
Levy RP, Gilger WG. Acute thyroid poisoning. N Engl J Med. 1957;256:459-460.
Boyd RE, Brennan PT, Deng JF, Rochester DF, Spyker DA. Strychnine poisoning. Recovery from profound lactic acidosis, hyperthermia, and rhabdomyolysis. Am J Med. 1983;74:507-12.
