Malignant Hyperthermia

Malignant hyperthermia is a life-threatening reaction to anaesthetic drugs. The term “malignant” hyperthermia arises from the progressive nature of the condition and its ultimate end in death associated with a very high body temperature if the condition is not recognised and treated promptly.

Between 1: 3,000 and 1: 10,000 people carry the genetic risk of developing malignant hyperthermia during anaesthesia.  Those at risk can receive anaesthetics safely as long as the inhalational anaesthetics and suxamethonium are avoided.

Malignant hyperthermia is the “disease of anaesthesia”.

By definition MH can only occur under general anaesthesia. This is to distinguish it from other forms of heat illness where an assessment of cerebral function is required to make the diagnosis.

The responsibility of the anaesthetist is to:

• minimise the possibility of an MH reaction occurring
• promptly recognise and initiate treatment when an MH reaction is suspected
• ensure a patient who has had a suspected MH reaction is appropriately counselled and referred for definitive diagnosis.