Paradoxical pseudomyotonia (PP)

We strongly recommend the testing of Cocker Spaniels and Springer Spaniels for this disorder as the incidence is estimated to be 2.5%.

PP produces episodes of myotonic-like generalised muscle stiffness after exercise. Episodes generally last less than 45 seconds but there are reports of more severe episodes associated with breathing difficulty (apnoea) and lack of oxygen (cyanosis).