How is malignant hyperthermia diagnosed?

Malignant hyperthermia is diagnosed primarily through a skeletal muscle biopsy that tests for the presence of abnormal ryanodine receptors, which are implicated in the condition. A biopsy involves taking a small sample of muscle tissue, which can then be examined for genetic mutations or functional abnormalities that contribute to malignant hyperthermia reactions. This testing method is crucial because it directly assesses the physiological responses of muscle cells to certain stimuli, such as halothane, caffeine, or other agents that could provoke a hypermetabolic state.

Other methods, such as blood tests, CT scans, or urine analysis do not effectively diagnose malignant hyperthermia because they do not evaluate the specific neuromuscular pathway involved in the disorder. For instance, blood tests might reveal elevated levels of certain enzymes during an episode, but they do not confirm the diagnosis itself. Similarly, imaging techniques like CT scans would not provide information related to the underlying muscular abnormality associated with malignant hyperthermia, and typical urine tests would also fail to identify the specific defect in muscle physiology. Hence, the skeletal muscle biopsy stands out as the definitive diagnostic test for this condition.