malignant hyperthermia

see also:

• heat illness and heat stroke
• fever - the febrile response to infections
• hyperthermia
  • neuroleptic malignant syndrome (NMS)
  • serotonin syndrome
  • amphetamine overdose
• wikipedia

• malignant hyperthermia (MH) is a type of severe reaction in susceptible people that occurs when given anaesthetic gases or suxamethonium
• affects one in 5,000 to 50,000 cases where people are given anesthetic gases
• some individuals with malignant hyperthermia susceptibility may develop MH with exercise and/or on exposure to hot environments
• in susceptible individuals, the medications induce the release of stored calcium ions within muscle cells causing excessive muscle contraction which then may cause:
  • hyperthermia
  • hypercatabolic state (and in those with liver impairment may precipitate hepatic encephalopathy
  • metabolic acidosis
  • rhabdomyolysis
• untreated, mortality is 75%, but treatment with dantrolene and cooling can reduce this to 5%

• susceptibility can occur due to at least six genetic mutations, with the most common one being of the RYR1 gene
• inheritance is autosomal dominant