The causes of head tremors in dogs may be various, but sometimes an exact cause cannot be found. Diagnosing the exact cause of tremors often entails a process of elimination, meaning the vet will test for several diseases, and if the dog ends up having none, the vet may call the head tremors idiopathic, meaning their cause is unknown. Because sometimes head tremors may be indicative of serious disorders, it's important to see a vet for proper diagnosis and treatment.
Possible Cerebellar Abnormalities
Head tremors can be indicative of damage to the _cerebellum, the part of the brain responsible for coordination. Typically, such tremors appear when the dog focuses on a task and moves toward a target. For this reason, they're often called intention tremors._ For instance, the affected dog may be sitting quietly when the owner puts a food bowl down, only to experience head and neck tremors start as he reaches for the food, according to Wendy C. Brooks, a board certified specialist in canine and feline practice and owner of Mar Vista Animal Medical Center in Los Angeles.
Side Effects of Drugs
When head shaking starts when a dog is prescribed a medication, read the list of potential side effects. Several medications may cause tremors. For instance, rhythmic tremors can be observed from ingestion of dopamine receptor blocking agents or anti-emetic drugs, according to Johnny, D. Hoskins, a diplomate of the American College of Veterinary Internal Medicine and owner of DocuTech Services in Baton Rouge, Louisiana.
Exposure to Toxins
In some cases, the sudden appearance of head tremors in dogs can be attributed to the accidental ingestion of toxins. Often, such tremors affect only the head initially but then progress to the rest of the dog's body, says Justine A. Lee, a board-certified critical care veterinary specialist and toxicologist working at Animal Emergency and Referral Center in Twin Cities, Minnesota. A few products known for containing toxins responsible for causing tremors include prescription drugs such as amphetamines and antidepressants, snail and slug baits, moldy foods, compost, mouse and rat poisons, and chocolate.
Idiopathic Head Tremors
When head tremors can't be explained, they're categorized as idiopathic. Typically, these involuntary tremors affecting the head and neck are repetitive and can be horizontal, as if the dog is saying "no," or vertical, as if the dog is saying "yes." These tremors generally last about three minutes, and the dog is alert; once they stop, the dog appears to be unaffected. These tremors are considered benign and do not have any short- or long-term effects. Commonly affected dogs are young to middle-age dogs; breeds including Dobermans, French bulldogs, Labradors and boxers are particularly predisposed.
Diagnosis and Treatment
When head tremors happen only occasionally, videotaping an episode and showing it to the vet can be helpful; so can keeping a journal of when they occur and how long they last. Diagnostic tests for head tremors may include ocular and neurological tests, MRIs and spinal fluid analysis. Treatment is based on the underlying findings. Because sometimes head tremors are confused with epileptic seizures, affected dogs may be prescribed the anti-seizure medication phenobarbital; however, in the case of idiopathic head tremors, this drug doesn't help; its long-term use risks harming the dog's liver.