Malignant hyperpyrexia is a potentially life-threatening condition that develops in people exposed to general anesthesia drugs. Less commonly, someone can develop the condition as a result of stress from exercising or exposure to extreme heat. The condition is also known as malignant hyperthermia or malignant hyperthermia syndrome.
Anesthetic drugs overwhelm the circulatory system of individuals who have malignant hyperpyrexia. Stress on the circulatory system can lead to death if it is not treated immediately. Symptoms of malignant hyperpyrexia include rapid heart and breathing rate, increased production of of carbon dioxide and consumption of oxygen, muscle rigidity, high temperature, in excess of 105 degrees Fahrenheit(40.5 C), an increase in the acidity of the blood, and a rapid breakdown in muscle tissue.
Symptoms of malignant hyperpyrexia develop rapidly after exposure to anesthesia, typically within one hour, although in rare cases it may take several hours for symptoms to develop. Treatment with dantrolene sodium can reverse symptoms. Dantrolene sodium is also given to individuals who are at risk of developing malignant hyperpyrexia, but must undergo general anesthesia for surgery; this will usually prevent the onset of symptoms. Additional treatment includes a cooling blanket to bring down temperature, and the introduction of intravenous and oral fluids to prevent kidney damage. Repeated incidences, even if treated rapidly, can lead to kidney failure.
Malignant hyperpyrexia is a genetic condition, and having a family member with the condition increases the likelihood of others having the condition. Only one parent has to carry the gene for malignant hyperpyrexia to pass the trait on. Avoiding general anesthesia is the only way to prevent problems in the future.
Any cases of unexplained death under anesthesia in the family should be discussed with a healthcare provider before undergoing general anesthesia. Additionally, anyone with a family history of muscular dystrophy or myopathy should consider genetic counseling before receiving general anesthesia. It is estimated that 1 in 100,000 individuals may have this condition. The mortality rate is roughly six percent.
It is important to note that general anesthesia medications, specifically the combination of anesthetic agents and neuromuscular blocking medications, creates the problem. Local anesthetics, such as lidocaine, and opiates, like morphine, do not trigger this condition. Individuals who may have the genetic trait for malignant hyperpyrexia should, however, avoid cocaine, ecstasy, amphetamines, and other stimulants, which may trigger similar symptoms.