If you notice your dog shaking, it could be normal or it could be a sign of something more serious: dog tremors. To know if your dog’s shaking is abnormal, it first helps to learn about what can cause shaking, trembling and shivering in dogs.
A dog might shake, tremble or shiver when he is cold, fearful, stressed, anxious, nervous, or even happy and excited. Dogs might also shake, shiver or tremble if they are sick or in pain. Tremors can look a lot like shaking, but they are inherently different.
“The definition of a tremor is an involuntary, rhythmic, muscle contraction and relaxation of one or more body parts,” explains Michelle Murray, DVM, MS, Dipl. ACVIM (Neurology), CCRT, owner of NEST Veterinary Neurology in San Clemente, California. “This would, in many cases, outwardly look like shaking. Some types of tremors/movement disorders occur all the time, some occur only during standing and some only occur during exercise.”
Seizures can also look like tremors. One major difference — a dog is usually awake and aware during an episode of tremors. With seizures, the dog is typically unconscious or less aware of his surroundings (he might seem “out of it”).
“There are many things that can cause tremors, or movement disorders, in dogs,” Dr. Murray says. “The study of tremors in animals is extremely complex. Additionally, there are many causes of tremors that are poorly understood, making treating them even more difficult.”
Two things cause dog tremors: diseases of muscle (called myopathies) or diseases of the nervous system (neuropathies and brain disorders). Tremors caused by muscle diseases can be inherited (the dog is born with that predisposition to developing that disease), acquired (caused by another disorder, such as hypothyroidism or Cushing’s disease) or caused by metabolic deficiencies.
“The common denominator with all of the myopathies (muscle diseases) is that the muscle membrane is not working properly, thus the muscle fibers are not contracting/relaxing normally,” Dr. Murray explains. “Neurologic causes of tremors involve abnormalities in the nerve signals going to the muscles. Clinically, these patients may tremor just like a dog with a muscle disease, however the disease is affecting the nerve cells, rather than the muscle cells.” Neurologic causes of tremors may also be inherited, or caused by toxins, the distemper virus and brain diseases.
Some breeds are predisposed to certain tremors/movement disorders. Just a few include Bulldogs, Cavalier King Charles Spaniels, Chow Chows, Dalmatians, Doberman Pinschers, Great Danes, Golden Retrievers, Miniature Schnauzers, Samoyeds, Scottish Terriers and Springer Spaniels. A specific tremor disorder called white shaker dog syndrome affects small white dogs like Maltese, Poodles and West Highland White Terriers.
If you suspect that your dog is having tremors, it’s important to have him examined by a veterinarian as soon as possible. Even though you might not be able to distinguish between shaking, tremors or seizures, it’s always a good idea to get your vet’s opinion when your dog is shaking or trembling and you can’t determine the cause.
“Since there are so many causes of tremors, involving various components of the nervous system, the diagnostic tests that we perform can vary widely,” Dr. Murray explains. “Because of this, the most important first step is a detailed, thorough history, physical exam and neurological exam.”
The vet will consider your dog’s genetic background, breed, age, travel history, vaccination history, whether any littermates are affected with the same symptoms, your dog’s diet and possible exposure to toxins. It is especially helpful to provide a very detailed description of what the tremors look like. Ideally, record a quick video on your phone when your dog is exhibiting the shaking or tremors in case they subside before your appointment.
Your vet will likely want to perform blood work and urinalysis, and possibly test for specific toxins if she suspects your dog is suffering from exposure to a poison. More advanced testing might include nerve and muscle biopsies, an MRI of the brain, cerebrospinal fluid analysis, and possibly genetic testing if you suspect an inherited disease.
“Treatment options vary widely depending on the underlying cause,” Dr. Murray explains. “If the tremors are benign and stop on their own, or only occur occasionally, we may not recommend treatment at all. With some of the causes, there are no effective treatments. The prognosis ultimately depends on the underlying cause and can vary widely.”
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