Malignant hyperthermia

Malignant hyperthermia is a genetic condition where the patient has a certain mutation in the gene for the ryanodine receptor, which causes enormous Ca2+ release from the sarcoplasmic reticulum in response to succinylcholine or inhaled general anaesthetics. It causes isotonic muscle contractions of all muscles in the body, which increases heat production. The increased energy need will cause a switch to anaerobic metabolism and therefore cause lactic acidosis. The muscle fibres can degenerate (rhabdomyolysis) which releases myoglobin into the blood, which can cause acute renal failure.

It is treated with dantrolene, a ryanodine receptor blocker, bicarbonate for the acidosis and physical cooling to prevent damage from the hyperthermia.