Malignant Hyperthermia is an autosomal dominant genetic mutation that can cause a dog to have dangerous physical reactions in response to specific triggers. The triggers include exposure to certain drugs, most notably the inhaled anesthetics like halothane, the ingestion of food ingredients such as caffeine and hops, and too much exercise. MH is also known as "canine stress syndrome" because the condition can become apparent when a dog is under stress or over-stimulated.
After experiencing one or more of the triggers, an affected dog can have extreme muscle contractions, increased metabolism, rapid heartbeat and elevated body temperature. The body produces too much carbon dioxide, and enters a hyper metabolic state. Muscles become rigid and stiff and seizures are a possibility.
If a dog with the MH mutation undergoes anesthesia using halothane or other types of inhaled anesthesia, the results can be quickly fatal. However, there are some forms of anesthesia that can be safely used to sedate dogs affected with MH. This is why it is important to identify dogs that have the mutation prior to scheduling surgical procedures. There is no cure for Malignant Hyperthermia, but dogs with this mutation can avoid stressful situations, intense exercise, and food and drugs that can trigger symptoms.