Malignant Hyperthermia (MH)

Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle elicited by exposure to volatile anesthetics and depolarizing muscle relaxants. The disorder is well recognized in humans and pigs, although a number of definite episodes have also been reported in dogs. When given above mentioned agents, MH-susceptible (MHS) dogs show tachycardia, hyperthermia, elevated carbon dioxide production, and death, if the anesthetic is not discontinued. Specific interventions, including use of the calcium release channel antagonist dantrolene, are efficacious in reversing signs of the canine syndrome. In most reports of MH in dogs, metabolic acidosis is moderate and muscle rigidity is minimal, in contrast to the severity of both in the swine or human condition.

Inheritance: autosomal dominant

Mutation: RYR1 gene

Genetic test: The method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs. Testing can be done at any age.