Perianesthetic Stress Hyperthermia
Another condition that Dr. Michael Court has been investigating in Scottish Deerhounds and Greyhounds is stress hyperthermia. When it occurs, it frequently is observed in association with an anesthetic episode for a surgical procedure (i.e. perianesthetic). Signs include an unexpected rapid increase in body temperature to more than 105°F, panting, and deep red mucous membranes. Treatment includes rapid cooling and administration of fluids and sedatives. According to a Greyhound medicine expert (Dr. Guillermo Couto, DVM), stress hyperthermia often can be prevented by judicious use of sedatives before a triggering event (veterinary visit), as well as taking other steps to minimize stress.
While stress hyperthermia is serious and potentially life-threatening, no Scottish Deerhound cases have been reported to Dr. Court that have been fatal. This differs from malignant hyperthermia, a more severe condition in dogs, which is invariably fatal.
Since not all Greyhounds or Deerhounds are susceptible to stress hyperthermia, a genetic predisposition has been suspected. With support from SDCA, Dr. Court has identified a mutation in the RYR1 gene of dogs with a history of stress hyperthermia. This mutation appears to be a milder form of the mutation that causes malignant hyperthermia in dogs.
Since we have studied only a limited number of dogs so far (8 Deerhounds and one greyhound), the usefulness of clinical testing for this mutation is unclear. Consequently, Dr. Court is continuing to recruit cases to see if the RYR1 mutation can explain all cases. Please contact his lab if you have a dog that has experienced hyperthermia to donate DNA (via a cheek swab).