What is malignant hyperthermia?

• A. An allergic reaction affecting lungs.
• B. A mild fever during anesthesia.
• C. A liver injury caused by drugs.
• D. A hypermetabolic crisis associated with rapid, uncontrolled release of calcium in skeletal muscles in response to triggering agents.

Answer: (D)

Malignant hyperthermia is a life-threatening hypermetabolic crisis of skeletal muscle caused by a genetic susceptibility. When susceptible individuals are exposed to triggering anesthesia agents (such as certain inhaled volatile anesthetics or the depolarizing muscle relaxant), calcium is released in large, uncontrolled amounts from the muscle cell’s sarcoplasmic reticulum via the ryanodine receptor. That sudden calcium surge drives excessive muscle contraction and metabolism, leading to rapid increases in carbon dioxide production, heat generation, acidosis, tachycardia, muscle rigidity, and can progress to rhabdomyolysis and organ failure if not treated. It is not an allergic reaction, nor a mild fever, nor a liver injury. Treatment centers on stopping triggers, giving 100% oxygen, administering dantrolene to halt the calcium release, and aggressive cooling and supportive care. Understanding this helps distinguish it from other perioperative fevers or reactions and underscores the need for prompt recognition and management.