What does malignant hyperthermia cause during general anesthesia?

Malignant hyperthermia is a life-threatening condition that can occur during general anesthesia, primarily in response to certain anesthetic agents, especially volatile anesthetics and succinylcholine. One of the hallmark signs of malignant hyperthermia is a rapid and extreme increase in body temperature, which can rise significantly in a very short period. This is due to an uncontrolled release of calcium from the sarcoplasmic reticulum in skeletal muscle, leading to increased metabolic activity and muscle hypermetabolism.

The fast rise in temperature can be so severe that it becomes critical, leading to complications such as muscle rigidity, acidosis, and a significant increase in oxygen demand. As the condition progresses, other symptoms may manifest, such as tachycardia and a rise in carbon dioxide levels, but the defining characteristic is indeed the rapid elevation of body temperature.

In contrast, while increased heart rate and respiratory depression can occur during general anesthesia due to various reasons, they are not specific to malignant hyperthermia. Allergic reactions are also a potential risk with anesthesia but are not a direct result of malignant hyperthermia. Thus, the primary and distinctive feature of malignant hyperthermia during general anesthesia is the acute rise in body temperature.