Question

A pt. Is undergoing surgery where anaesthesia is maintained on halothane. The pt. Developed hyperthermia & m/s rigidity. Which of the agents is responsible?

• A. D-tubocurarine
• B. Suxamethonium
• C. Cisatracurium
• D. Rocuronium

Answer 1

The Correct Option is B

The clinical scenario described is indicative of a condition known as malignant hyperthermia, a life-threatening reaction to certain anesthetics and muscle relaxants. In this specific case, the patient under halothane anesthesia experienced hyperthermia and muscle rigidity, classic signs of malignant hyperthermia.

The agent responsible for triggering this reaction is Suxamethonium (also known as succinylcholine). Suxamethonium is a depolarizing neuromuscular blocker that can predispose susceptible individuals to malignant hyperthermia, especially when used in conjunction with volatile anesthetics like halothane.

To understand why suxamethonium is the causative agent, consider the following pathophysiological steps:

• Predisposition: Genetic sensitivity to certain agents due to mutations in the ryanodine receptor gene (RYR1) or other related genes.
• Exposure to triggering agents: Volatile anesthetics and depolarizing muscle relaxants like suxamethonium.
• Pathophysiological response: Uncontrolled release of calcium from the sarcoplasmic reticulum in skeletal muscles, leading to excessive heat production and muscle rigidity.
• Clinical manifestations: Rapid rise in body temperature, muscle rigidity, tachycardia, and potential for severe complications if not promptly treated.

Therefore, in the given options, Suxamethonium is the agent responsible for causing these symptoms.