Watch a dog sleep and eventually he will start to twitch, leaving you to wonder if he is dreaming of chasing rabbits across the yard. If a dog twitches or shakes while he's awake, however, things could be a lot more serious. Like people, dogs twitch for numerous reasons. While some are easily explained, others could be signs of a larger illness.
Sleep Twitching is OK
Twitches are involuntary muscle contractions. When your dog is asleep, chances are that any twitching is related to REM, just as it is in people. While the jury is still out on whether dogs actually dream of chasing critters or playing with others, their involuntary sleep movements mirror those of their human counterparts. There is no need to wake your dog because he won't hurt himself.
Myokymia is the contraction of small bands of muscle fibers, which causes twitching in the overlying skin. This is common during sleep or under anesthesia and most commonly occurs on a dog's face. However, outside of sleep or anesthesia, myokymia can be a sign of a more serious disorder. The condition may result from a variety of central or peripheral nervous system disorders, including distemper, demyelination -- in which the sheaths of neurons are damaged -- or autoimmune disease.
Shivering and Trembling
Dogs shiver for the same reasons people do -- they're cold, they're old or they're nervous. But more serious causes of trembling in dogs can stem from eating toxic foods (like chocolate). These shakes usually come with other issues, such as diarrhea or vomiting. Distemper also causes shaking, as well as noticeable eye and nose discharge, fever, and coughing fits.
Cause of Other Muscle Movements
In some cases, the cause of a dog's tremor simply cannot be determined. This is called generalized tremor syndrome. In other cases, shaking could be due to an injury, a reaction to a drug or chemical, a nervous system disease such as epilepsy, or as a side-effect of kidney failure. Tremors may also stem from low blood-sugar in dogs.
Certain breeds tend to be more genetically susceptible to trembling. The condition is so prevalent,in fact, that these breeds are often called "shaker dogs." Typically affected breeds include chow chows, springer spaniels, Samoyeds, Weimaraners, Dalmatians, Doberman pinschers, English bulldogs and Labrador retrievers.
Generally, involuntary muscle movements in dogs are symptoms of an underlying issue. Once that issue is treated -- for example, he's given medicine to countermand the effects of having eaten paint chips -- the shaking goes away. In other cases, your vet will likely prescribe drugs to help control or halt the movements. Never over-exert a dog with a tremor disorder, as it will only aggravate his condition. Consult your vet if shaking remains persistent.