White Shaker Syndrome in Dogs

Tremors are involuntary and repetitive contractions of muscles. The tremors seen in white shaker syndrome can range from mild shivering to severe full body tremors that don’t seem to cause any pain. The syndrome generally develops suddenly in young, small to medium dogs between 6 months to 5 years of age. Often, the tremors are mistaken for being cold or nervous, but they can be a sign of a more serious nervous system problem. As such, if your dog is experiencing tremors, it is best to seek a veterinary opinion as soon as possible. White shaker syndrome is often harmless, but in rare cases, seizures can occur.

White shaker syndrome is a condition of generalized tremors that are present without any infectious or other known cause. It gets its name from the small white dogs it commonly affects, such as Terriers and Maltese, though it has been seen to affect other non-white and larger breeds. It is also called little white shakers syndrome or generalized tremor syndrome.

• Head and body muscle tremors
• Shivering
• Incoordination
• Uncontrolled rapid eye movements 
• Hypermetria, or when movement overreaches the intended goal
• Head tilt
• High-stepping gait
• Difficulty walking
• Loss of menace response 
• Paralysis 
• Seizures

The true cause of white shaker syndrome is unknown, but there are some ideas as to why it can occur. It has been theorized to be caused by:

• Inflammation of the cerebellum, which regulates voluntary muscle movements
• Inflammation of the spinal cord and the covering of the brain 
• Nonsuppurative encephalomyelitis
• Neurotransmitter deficiency mediated by the immune system that affects the levels of melanin, dopamine and norepinephrine
• Congenital condition

White shaker syndrome seems to affects certain breeds more frequently, so there may be a genetic component to this condition. Breeds commonly affected have included:

• Maltese 
• West Highland White Terrier
• Bichon Frise
• Poodle
• Samoyed 
• Dachshund
• Boston Terrier
• Lhasa Apso

Tremors can be the result of a myriad of causes, such as congenital diseases, metabolic conditions, various intoxications, bacteria and viruses, or from a mycotoxin. Your veterinarian will perform several exams and tests to determine the cause of your dog’s tremors. A diagnosis of white shaker syndrome is often based on ruling out all other causes through diagnostic testing. Relay to your veterinarian a complete history of the symptoms, as well as any behavioral changes or possible exposures to toxins or infectious agents. Your veterinarian will then conduct a physical, orthopedic, and neurological exam. 

Tests can include a urinalysis, complete blood counts and a biochemistry analysis to assess metabolic functions, look for infectious agents, and reveal inflammation. Electromyography (EMG) uses electrical signals to assess muscle and nerve health. Muscle or nerve biopsies may also be taken and analyzed. An MRI or CT scan may be used to look at the state of the brain. Finally, cerebrospinal fluid is often collected through a spinal tap, then analyzed to determine the functionality of the nervous system, as well as to look for inflammation and infectious disease. As other possible causes are ruled out, a diagnosis of white shaker syndrome can be given when no other cause can be determined.

Treatment is primarily through medication. Many dogs can have their tremors completely disappear with the administration of a combination of immunosuppressive corticosteroids, which can suppress inflammation, and benzodiazepines, a class of drugs that helps anxiety by reducing nerve activity. These are generally started at high doses that are tapered to a lower dose or discontinued over time.

Tremors have been known to cease within a few days to two weeks of treatment, but the drugs are given for several months to prevent them from recurring. If treatment is discontinued and the tremors return, your dog may need continued therapy. While for many animals, this treatment is quite effective, some dogs may need a continued low dose drug regiment throughout their lives. 

Treatment is most often given at home, but severe cases may require hospitalization. Additional medications, such as barbiturates or anticonvulsants, may be given to help eliminate the tremors. 

Recovery is generally good for most dogs affected by this syndrome. You will be given medications to administer to your dog at home, and will need to bring your dog in to your veterinarian every few weeks during treatment to monitor his progress, change dosage levels, and check for any side effects from the medications. On average, treatment can help tremors to cease within days, and your dog will be able to discontinue treatments after several months. A relapse can occur, in which case treatment is continued, and may be needed throughout your dog’s life to control the tremors. There is not enough known about the hereditary implications of white shaker syndrome, but breeding affected dogs is still discouraged.