There is mutation of gene coding for the ryanodine receptors in malignant hypehermia. Which of the following statements best explains the increased hea production in malignant hypehermia
**Core Concept**
Malignant hyperthermia (MH) is a life-threatening medical emergency triggered by certain anesthetics, particularly volatile inhalational agents and succinylcholine. It is characterized by an uncontrolled increase in muscle metabolism, leading to excessive heat production and muscle rigidity. The condition is often associated with mutations in genes encoding for ryanodine receptors (RyR1), which play a crucial role in regulating calcium release from the sarcoplasmic reticulum in skeletal muscle cells.
**Why the Correct Answer is Right**
In MH, the mutation in the RyR1 gene leads to an abnormal increase in the release of calcium ions from the sarcoplasmic reticulum. This results in a sustained contraction of skeletal muscle cells, known as a rigor, which in turn leads to increased energy production through anaerobic glycolysis. The excess heat generated during this process is released into the body, causing a rapid increase in body temperature. The increased calcium release also activates the enzyme phosphocreatine kinase, which further contributes to the increased energy production and heat generation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the pathophysiology of malignant hyperthermia.
**Option B:** While increased activity of the sarcoplasmic reticulum's calcium channels is a contributing factor, it is not the primary mechanism by which malignant hyperthermia leads to increased heat production.
**Option C:** This option is incorrect as the increased heat production in malignant hyperthermia is not primarily due to the breakdown of ATP, but rather the increased production of ATP through anaerobic glycolysis.
**Clinical Pearl / High-Yield Fact**
In the context of malignant hyperthermia, it is essential to recognize the clinical signs, including muscle rigidity, tachycardia, and an elevated end-tidal CO2. The condition requires immediate treatment with dantrolene, which helps to reduce the abnormal calcium release from the sarcoplasmic reticulum.
**Correct Answer:** C.