Definition
A tremor is an involuntary, oscillating, rhythmic twitching of opposing muscle groups in all or part of the body. Tremors are usually visible to the naked human eye and can be felt when touching affected areas.
How Tremors Affect Dogs
Tremors are fairly easy to differentiate from seizures because of their regularity. They can occur during rest or activity, but often tend to worsen with activity or excitement and lessen with rest or sleep. They can be generalized or localized. Generalized tremor syndrome tends to occur in young to middle-aged animals and may be more common in white-coated dogs. Localized tremors typically involve the head or the rear limbs. Small breed dogs are more frequently affected by generalized tremors. Owners often describe their dog as “shaking” or “shuddering”.
Causes of Tremors in Dogs
Tremors are caused by the synchronous contraction of reciprocally innervated, antagonistic muscles, leading to a regular to-and-fro movement in all or part of an affected dog’s body. The underlying cause of tremors is often unknown (idiopathic). Tremors generally can be related to genetic or developmental conditions, trauma, compressive lesions of the spinal cord, inflammation, exposure to any of a number of tremorgenic toxins, poor blood perfusion to pelvic muscles due to cardiac disease, immune-mediated diseases, metabolic diseases and degenerative diseases of the nervous system. Certain breeds appear predisposed to developing tremors, and certain medications can induce tremors. There may be other causes as well.
Preventing Tremors in Dogs
Dogs with tremors should be kept as free from stress or inordinate excitement as possible. Excessive exercise should be avoided. Dogs with tremors should be evaluated by a veterinarian as soon as possible.
Special Notes
Many causes of canine tremors are treatable, often with immunosuppressive doses of corticosteroids, although in very young dogs tremors can reflect non-reversible genetic or developmental abnormalities. If tremors begin after exposure to a chemical, owners should remove access to the compound and take the dog and chemical packaging to the veterinary hospital immediately.