Malignant Hyperthermia (MH) is a rare genetic condition that causes adverse reactions to anaesthetic drugs. It results in the body rapidly overheating and is sometimes fatal. There is now a DNA test available to identify if a breeding dog is carrying this condition.
Mode of Inheritance: autosomal dominant
Malignant hyperthermia (MH) is an inherited disorder of skeletal muscle characterised by hypercarbia, rhabdomyolysis, generalised skeletal muscle contracture, cardiac dysrhythmia, and renal failure that develops on exposure to volatile anaesthetics and depolarizing muscle relaxants. When given these agents, MH-susceptible dogs show tachycardia, muscle contractions, hyperthermia, elevated carbon dioxide production, and death if the aesthetic is not discontinued. Malignant hyperthermia can be triggered in susceptible animals by excitement, apprehension, exercise, or environmental stress. Because of this reason, this disorder is also known as “canine stress syndrome.”
MH episodes usually come on unexpectedly and are very serious. If the condition is recognised early enough in an animal under anaesthesia, certain measures can be taken in order to be able to save the animal. Some types of anaesthesia can be fatal for dogs with MH gene. This is why it is also important to identify dogs that carry the MH gene prior to surgical procedures. Unfortunately, regardless of treatment, MH is usually fatal. Some types of anaesthesia can be fatal for dogs with MH gene.
Further reading:
Roberts, M.C., Mickelson, J.R., Patterson, E.E., Nelson, T.E., Armstrong, P.J., Brunson, D.B., and Hogan, K. (2001). Autosomal Dominant Canine Malignant Hyperthermia Is Caused by a Mutation in the Gene Encoding the Skeletal Muscle Calcium Release Channel (RYR1). Anesthesiology 95, 716–725 – 716–725.
