Episodic Falling Syndrome

Episodic falling syndrome is an inherited condition seen in Cavalier King Charles Spaniels in which episodes of muscle stiffness occur during excitement or exercise. The muscles of the legs and sometimes the trunk become rigid, causing the dog to freeze, lean, or collapse without losing consciousness. Episodes typically last seconds to minutes and resolve on their own. Owners often describe their dog suddenly becoming stiff-legged during a walk or play, sometimes described as looking 'deer-like' or as though the dog's legs are locked. The dog remains aware throughout, and there is no seizure activity. Episodes tend to begin in early life, though severity and frequency vary between individuals. This page explores the patterns that may signal episodic falling syndrome, the mechanism underlying the muscle stiffness, how the condition is investigated and distinguished from other causes of collapse, and the approaches available for managing episodes over time.