Which is true about Malignant Hyperthermia triggers?

• A. Dehydration
• B. Exercise during hot weather
• C. A viral infection
• D. Certain drugs used for general anesthesia

Answer: (D)

Malignant hyperthermia risk is activated by exposure to specific anesthetic drugs in susceptible people. The triggers are certain drugs used for general anesthesia, especially volatile inhaled anesthetics and the depolarizing muscle relaxant succinylcholine. When a susceptible individual is exposed, these agents cause an uncontrolled release of calcium from the sarcoplasmic reticulum in skeletal muscle. That calcium surge drives sustained muscle contraction and a dramatic rise in metabolism, producing rapid heat, high carbon dioxide production, metabolic acidosis, tachycardia, and eventually rhabdomyolysis and organ damage. Because of this, anesthesia drugs are the true triggers.

In contrast, dehydration, exercising in hot conditions, or a viral infection do not by themselves trigger malignant hyperthermia. They can cause heat-related illness, but MH is specifically triggered by the anesthetic agents. Recognizing this helps ensure that anyone with MH susceptibility avoids triggering drugs and that dantrolene and cooling measures are available if a trigger is encountered.