What it is
Muscles move smoothly because the nerve signals that tell them to tighten are balanced by signals that let them relax. This disorder is linked to an imbalance of serotonin, one of the nervous system's chemical messengers: when the dog gets excited or exerts itself, the relaxing signals fall behind, the muscles tighten all at once, and the dog moves stiffly until it calms down.
The disorder is inherited, and the first episodes appear in puppyhood or early adulthood. Between episodes the dog is healthy and active.
Life with an affected dog is about learning what sets off an episode: wild games, meeting other dogs, or the excitement before a walk. Calm routines, short play sessions with breaks and a quiet place to settle all help. Keep a note of when episodes happen so you can tell your vet.
Signs you may notice
- Stiff, stilted gait
- Hind legs that do not bend
- Arched back during play
- Falls over when excited
- Moves normally after a rest
During play or running the dog's gait may turn stiff, the hind legs seem not to bend, the back arches and sometimes the dog even falls over. Between episodes it seems completely well, so it helps to film an episode and show it to a vet.
When to see a vet
Book a visit if your dog has episodes of stiffness or falling during play or excitement, and bring a video if you can. If your dog loses consciousness, paddles its legs or an episode does not stop after a rest, a vet is needed immediately.
This is general information, not veterinary advice. For your own dog's health, tests and treatment, see a vet.