What are the classic signs of malignant hyperthermia and the immediate treatment protocol?

• A. Rapid rise in end-tidal CO2, tachycardia, muscle rigidity; administer dantrolene, stop triggering agents, hyperventilate with 100% oxygen, and initiate cooling
• B. Hyperthermia with skin rash; treat with antihistamines
• C. Slow rise in end-tidal CO2, bradycardia; treat with cooling and fluids
• D. Low end-tidal CO2, hypotension; administer epinephrine

Answer: (A)

The key concept here is recognizing malignant hyperthermia by its early, unmistakable signs during anesthesia and knowing the immediate, life-saving steps to stop the reaction and support the patient. The most reliable early clue is a rapid rise in end-tidal CO2, reflecting an abrupt increase in metabolic activity from uncontrolled calcium release in muscle cells. That hypermetabolic state also drives a fast heart rate and generalized muscle rigidity as the muscles contract vigorously.

Act quickly to stop the trigger and address the cascade. Stop any triggering agents right away and summon help for a malignant hyperthermia protocol. Deliver 100% oxygen and ventilate aggressively to normalize ventilation and oxygenation. Give dantrolene as soon as possible because it directly blocks calcium release from the sarcoplasmic reticulum, halting the hypermetabolic process. The initial dose is about 2.5 mg/kg IV, and it can be repeated up to a total of roughly 10 mg/kg as needed until the signs subside.

In parallel, begin cooling to control the escalating core temperature and metabolic rate, using ice packs, cooled IV fluids, and cooling blankets. Monitor and correct metabolic disturbances that accompany MH: address acidosis, manage potassium shifts, and support renal function with adequate hydration. Continuous monitoring of vital signs, ABGs, electrolytes, and CK levels guides ongoing therapy and escalation of dantrolene dosing.

The other scenarios don’t fit malignant hyperthermia: a fever with a skin rash points toward an allergic reaction; a slow CO2 rise with bradycardia isn’t the typical MH pattern; and low CO2 with hypotension aligns more with other anesthetic or cardiovascular issues and not the classic MH sequence.