Sustained hyperthermia leads to several serious acute complications. Hypovolaemia from sweating and vasodilation reduces cardiac output and hinders thermoregulation. Muscle breakdown leads to hyperkalaemia, myoglobinuria, and acute renal failure. Endothelial damage results in disseminated intravascular coagulopathy. Most importantly, sustained hyperthermia causes acute brain damage and convulsions.
Death is often sudden and probably the result of a cardiac arrhythmia.
Initially, signs and symptoms may differ according to the drugs involved. An inherited syndrome in which certain anaesthetic agents cause widespread muscle cell contraction leading to massive heat production and acute lactic acidosis. A syndrome characterized by mental confusion, muscle rigidity, diaphoresis, and hyperthermia in patients taking potent antipsychotic drugs. May occur after first dose or during regular treatment. Mechanism is thought to be related to CNS dopamine blockade.