Malignant Hyperthermia Differential Diagnoses

Updated: Jul 24, 2020
  • Author: James W Chapin, MD; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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Diagnostic Considerations

In addition to the conditions listed in the differential diagnosis, there are a number of other conditions and circumstances that may mimic malignant hyperthermia (MH), including the following:

  • Contrast dye
  • Diabetic coma
  • Drug toxicity
  • Environmental heat gain
  • Equipment malfunction, increased carbon dioxide, rebreathing, soda lime exhaustion
  • Exercise hyperthermia
  • Freeman-Sheldon syndrome
  • Hypokalemic periodic paralysis
  • Intracranial free blood
  • Muscular dystrophies (eg, Duchenne and Becker)
  • Myotonia
  • Ventilation problems

Although its clinical picture is similar to that of MH, neuroleptic malignant syndrome (NMS) is caused by the central effects of drugs with dopamine antagonist properties, including antipsychotics (eg, haloperidol) and antiemetics (eg, metoclopramide and droperidol). The onset of the syndrome occurs hours to days after initiation of treatment with the drug.

Clinically, a patient with NMS displays motor impairment, rigidity, akinesia, or extrapyramidal signs. Mental status deteriorates, and coma or delirium may develop. Hyperpyrexia is noted, with dehydration and hypotension. The duration is 7-10 days. Treatment consists of stopping the drug, controlling the symptoms, and administering dopamine agonists (eg, bromocriptine). Dantrolene will lower the temperature.

Differential Diagnoses