Vestibular disease arises from pathology of the inner ear (peripheral) and/or brainstem (central) in the area of the origination of the cranial nerve that controls vestibular function. The vestibular nerve and inner ear control sense of balance and sense of one’s surroundings.
Both dogs and cats of any age and breed can be affected. Signs of vestibular disease are most often a head tilt; nystagmus (erratic eye movement); ataxia or an unsteady gait; falling, circling and/or rolling; nausea, vomiting and/or anorexia; deviation of the eye(s) from normal position. If the cause is an external ear infection that extends into the inner ear, dark discharge in the ear, odor, head shaking and/or scratching at the ear may be noted, as well. Cats can also develop benign, soft tissue growths (polyps) in the ear with chronic inflammation (chronic upper respiratory infections for instance). When brainstem disease (such as a tumor) is the cause, other signs of cranial nerve dysfunction (for example, droopy eyelids and lips and loss of sensation of the face) are often observed. Surgery of the inner ear can also cause vestibular signs. Cats that have surgery to remove polyps, for example, are often affected with vestibular signs for a period of time after surgery.
In older dogs, idiopathic vestibular disease can develop. We do not know the cause and there is really no definitive treatment. It comes on very suddenly and usually disappears just as suddenly with time. Supportive and symptomatic therapy is given until signs resolve enough for the dog to get around, drink and eat well on its own. The important thing in an older dog is to distinguish idiopathic disease from brainstem disease involving neoplasia/cancer.
If an external ear infection is the culprit, definitive treatment involves thorough cleaning of the ear by flushing and/or opening up the bone which houses the inner ear. Antibiotics, both topically and systemically, are needed. Once an infection is deep withi n the ear, treatment may need to be administered for weeks to completely clear it, but the prognosis is generally good.
Definitive therapy for brainstem disease is much more difficult. There is a possibility that a tumor could be removed surgically, but this area is very difficult to physically reach and many tumors extend deep into the brainstem and full excision may not be possible. Infectious or immune-mediated diseases can affect the brainstem as well and can be treated, but many times the prognosis is still not very good.
The prognosis for old dog idiopathic disease is good. It can be quite difficult for the owner to watch their dog in that condition, but if they can bear with it, the dog will recover. In some instances, a residual head tilt may develop but is usually very mild. Owners should realize that the dog may have repeat episodes, but again they usually recover quite well (unless another underlying cause develops).
It is important to seek the attention of a veterinarian for supportive and symptomatic treatment, as vestibular patients can be quite confused, anxious and uncomfortable. We also need to ensure that they stay well hydrated and obtain nutritional support. At home, the owner must be willing to help the animal get to its food and water and protect it from falling down stairs or off other heights.