Dogs may shiver or shake for several reasons. They may shake from excitement, because they are cold, when they experience pain, as a result of illness or medical conditions, or for reasons that are completely unknown. Some dog breeds inherit a predisposition to tremors.

Moore says that “tremors can be caused by a variety of problems, such as behavioral causes (fear, anxiety), electrolyte imbalances, problems of the nerve or muscle, weakness/fatigue, exposure to certain toxins, and problems in certain areas of the brain such as the cerebellum.”

The shaking you see is due to the muscles in his legs contracting, which needs to happen in a normal fashion so your dog can walk and run. The reason for the unintentional muscle contraction can often be difficult to determine.

Stress and excitement is thought to potentially exacerbate the head tremors. There is no known cause for Idiopathic Head tremors, and it is considered idiopathic. Most neurologist don’t believe this as a true seizure, but rather as a paroxysmal dyskinesia.

The most common head tremors do not have a known cause, but there are other types of head tremors that have certain causes such as:

• Injury or trauma to the head.
• Certain medications.
• Extreme pain.
• Renal (kidney) disorders.
• Low blood sugar.
• Low calcium level.
• Toxicity from chemicals or plants.

In summary, IHTS is a benign condition resulting in focal head tremors in dogs. Affected dogs do not typically respond to treatment nor is treatment indicated. The condition does not progress to include other neurological deficits and often will spontaneously regress over time.

Affected dogs typically develop tremors during early adulthood, at one to two years of age. Tremors are rhythmic, repetitive, and involuntary muscle movements, that look like ‘shaking’. Tremors may be localized to one area of the body (for example, the head) or may involve the entire body.

Some common poisons that result in tremors include:

• Compost poisoning.
• Tremorgenic mycotoxins (found in moldy food or garbage)
• Prescription antidepressants.
• Prescription amphetamines (used for ADD/ADHD in humans)
• Snail and slug bait containing metaldehyde.
• Certain types of mouse and rat poison containing bromethalin.

Ordinary table foods like grapes and raisins; certain commercial jerky treat products; common OTC medications like aspirin or other nonsteroidals (NSAIDs); or prescribed medications can all cause kidney disease. Venoms, pesticides and heavy metals are less common toxins.