The following are the most common reasons for referral for investigation of MH susceptibility:
- Family history of malignant hyperthermia.
- Adverse reaction to general anaesthesia where a trigger agent has been used, involving any combination of signs of increased metabolism (unexplained increase in carbon dioxide production, tachycardia, temperature increase<s>)</s>, muscle rigidity, rhabdomyolysis, disseminated intravascular coagulation and/or death. Initial signs should be evident during anaesthesia or within 60 minutes of discontinuation of anaesthesia.
- Family history of unexplained perioperative death.
- Postoperative rhabdomyolysis after clinical exclusion of other myopathies.
- Exertional rhabdomyolysis / recurrent rhabdomyolysis or persistently raised serum creatine kinase concentration of unknown cause (idiopathic hyperCKaemia) where no cause has been identified following neurological work-up.
- Exertional heat stroke requiring hospital admission, where known predisposing factors have been excluded.
- Myopathy and detection of an uncharacterised, rare, potentially pathogenic RYR1variant.