Exercise-induced malignant hyperthermia in an English springer spaniel.

An exercise-induced malignant hyperthermia-like syndrome developed in an English Springer Spaniel. Moderate exercise resulted in pronounced hyperlactacidemia, dyspnea, and hyperthermia. Before exercise, the dog had high activities of serum muscle enzymes, mild reticulocytosis, abnormally increased erythrocyte osmotic fragility, and a positive result from the caffeine-halothane contracture test. This report supports the hypothesis of a canine stress syndrome and indicates a role for exercise/challenge tests in diagnosis of malignant hyperthermia susceptibility.