Why does my dog keep twitching or having spasms?

If a dog twitches while sleeping, it is usually because it is dreaming, or the environment is too noisy and its sleep is restless. If the dog twitches while awake, and the spasms involve sticking out the tongue, stiff limbs, or loss of bowel or bladder control, it is generally a disease-related seizure – possibly epilepsy, meningitis, or after-effects of canine distemper – and the dog should be taken to a veterinary hospital for a clear diagnosis once the episode subsides.

Finally, dog poisoning can also trigger spasms; if it recently ingested a foreign object, seek veterinary treatment promptly.