How is malignant hyperthermia diagnosed and treated in patients with a congenital myopathy?

Updated: Mar 11, 2019
  • Author: Matthew Harmelink, MD; Chief Editor: Amy Kao, MD  more...
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Answer

Patients with central core disease (CCD) (less frequently with multicore disease) are inclined to develop malignant hyperthermia. However, since the precise diagnosis may not be known, precautions should be taken in all patients with a presumed diagnosis of congenital myopathy. General anesthesia usually triggers a full-blown episode, but excessive heat, neuroleptic drugs, alcohol, or infections may trigger milder episodes.

If surgery is required, these patients (and their relatives) should avoid inhaled anesthetics (except nitrous oxide) and succinylcholine.

Signs and symptoms of malignant hyperthermia include the following:

  • Elevated pCO2

  • Muscle rigidity

  • Tachycardia

  • Hemodynamic instability

  • Hyperventilation

  • Cyanosis

  • Lactic acidosis

  • Fever

  • Hyperkalemia

  • Hypercalcemia

  • Myoglobinuria

  • Death may result from pulmonary edema, coagulopathy, ventricular fibrillation, cerebral edema, or renal failure

Appropriate treatment includes the following:

  • Stopping inhalational anesthetics or succinylcholine

  • Hyperventilating the patient with 100% oxygen

  • Administering dantrolene up to 10 mg/kg

  • Providing bicarbonate for metabolic acidosis

  • Cooling the patient

  • Monitoring for arrhythmias and hyperkalemia

  • Maintaining urine output over 2 mL/kg/h

  • Avoiding calcium antagonists and beta-blockers

  • Monitoring in an ICU for 24–48 hours


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