Agent causing malignant hypehermia is?
**Core Concept**
Malignant hyperthermia (MH) is a severe, life-threatening complication of general anesthesia, triggered by specific volatile anesthetics and depolarizing muscle relaxants. It is characterized by a rapid increase in body temperature, muscle rigidity, and metabolic acidosis.
**Why the Correct Answer is Right**
Halothane, a potent inhalational anesthetic, can trigger MH by releasing calcium ions from the sarcoplasmic reticulum, leading to excessive muscle contraction and heat production. This is mediated by the ryanodine receptor 1 (RyR1) on the sarcoplasmic reticulum, which is sensitive to the specific anesthetic agents that cause MH. The pathophysiology involves an abnormal calcium release channel, leading to a cascade of events resulting in muscle rigidity, hyperthermia, and metabolic acidosis.
**Why Each Wrong Option is Incorrect**
**Option A:** Succinylcholine is a depolarizing muscle relaxant, but it is not typically associated with malignant hyperthermia.
**Option B:** Propofol is a commonly used intravenous anesthetic, but it is not known to trigger malignant hyperthermia.
**Option C:** Nitrous oxide is a commonly used inhalational anesthetic, but it is not typically associated with malignant hyperthermia.
**Clinical Pearl / High-Yield Fact**
Malignant hyperthermia can be triggered by specific volatile anesthetics (e.g., halothane, isoflurane, sevoflurane) and depolarizing muscle relaxants (e.g., succinylcholine). It is essential to have a clear anesthetic plan and be aware of the patient's history of MH susceptibility before administering these agents.
**Correct Answer: D. Halothane**