Summary

• A potentially lethal syndrome usually triggered by inhalation anaesthetics or suxamethonium.
• The underlying genetic susceptibility is most often due to a range of autosomal-dominant mutations in RYR1.
• Caused by an increase in metabolic rate driven by an increase in intracellular calcium levels in muscle.
• Presents with increased carbon dioxide production, hyperthermia, muscle rigidity, tachycardia, and metabolic acidosis.
• A definitive diagnosis requires muscle contracture testing after the acute episode has resolved.
• The mainstay of treatment includes discontinuation of the triggering agent, administration of intravenous dantrolene, and maintenance of normal core temperature.
• Rhabdomyolysis, renal failure, hyperkalaemia, and DIC are frequently seen.
• If the diagnosis is confirmed, first-degree relatives must be contacted and tested.