The vestibular system is a complex network of sensors within the inner ear and the brain that helps an animal maintain balance, and thus remain upright while walking, standing, or sitting. Most animals have a vestibular system, including humans. This delicate system can be disrupted by many things, leading to difficulty with balance.
Vestibular disease tends to strike dogs suddenly, and with very noticeable symptoms. The dog may be dizzy and falling over to one side. The head and eyes may be in an unusual position. The dog may be vomiting as well. These signs are consistent with vestibular dysfunction, which often heals on its own, depending on the cause.
What Is Vestibular Disease?
Vestibular disease occurs when there is a problem with the vestibular system. The vestibular system is a part of the nervous system that controls balance and eye movements. It includes the inner ear, the brainstem, a part of the brain called the vestibulocerebellum, and a cranial nerve in that area called the vestibulocochlear nerve. The vestibular system enables animals (including humans) to maintain balance and orient themselves according to head position. It also allows their eyes to follow movement without getting dizzy.
If one or more of these areas becomes impaired, the dog will exhibit signs of vertigo—a sensation that the room is spinning—and is considered to have some form of vestibular dysfunction. You might also hear this disorder referred to as "old dog vestibular disorder," as it most often strikes older dogs, although it can at times affect young dogs as well.
Symptoms of Vestibular Disease in Dogs
Most dogs with vestibular dysfunction will first appear clumsy and disoriented. This is because they experience vertigo due to the problem in the vestibular system. Often, the symptoms start quite suddenly. Vestibular disease is sometimes misinterpreted as a stroke, but this is not the usual cause. Common symptoms include:
Commonly, dogs with vestibular disease feel quite dizzy. This generally shows as staggering, walking in circles, inability to walk in a straight line, or wobbling. Your dog might not want to stand or walk at all, or might try to walk but fall over. A head tilt is common, and you'll notice that your dog drifts in the same direction as the head tilt when walking. The dizziness might cause your dog to vomit. If you look closely, you'll probably notice that your dog's eyes are moving quickly back and forth or up and down; this is called nystagmus.
Causes of Vestibular Disease
Vestibular dysfunction occurs when there is a disturbance in the vestibular system. The problem may originate in the inner ear, the brain, or both. There are several possible reasons why this might happen.
- Inner/middle ear infection (inflammation causes damage to the sensors in the inner ear)
- Tumor or cyst pressing on a nerve or other essential part of the brain or inner ear
- Trauma/injury to the brain and/or inner ear
- Hypothyroidism (a common disease but an uncommon cause of vestibular dysfunction)
- Vascular accident or stroke (an uncommon reason for vestibular disease)
- Idiopathic vestibular syndrome, which means that there is no obvious or known cause for the disorder
Diagnosing Vestibular Disease in Dogs
Your veterinarian will perform a full physical examination of your dog and probably will also draw blood and urine samples to check for signs of systemic disease or dysfunction. X-rays of your dog's head may be ordered to check for tumors or structural abnormalities. Your own description of your dog's symptoms will also be helpful.
If all tests are normal, and especially if your dog is a senior, the diagnosis will probably be idiopathic vestibular syndrome, which is the most common form of this disorder.
Treatment options for vestibular disease depend on the reason for the problem.
In the case of idiopathic vestibular syndrome, treatment involves supportive care until the signs resolve on their own. Most dogs recover from the worst of the symptoms within a couple of days, although full recovery can take months, and for some dogs, the head tilt is permanent. Anti-vertigo medications like meclizine are often prescribed along with anti-nausea drugs. The treatment is similar if the cause of the vestibular dysfunction was a stroke or vascular accident.
Dogs that have experienced trauma to the vestibular system may improve with supportive care (like those with idiopathic vestibular syndrome). Some are candidates for surgery to repair the damage. Hospitalization with intensive care may be needed during recovery.
If the vestibular disease is secondary to hypothyroidism, the vet will begin thyroid supplementation. Supportive care may be needed at first until the medication begins to work.
If the dog has an inner or middle ear infection, then the treatment may involve topical ear medications and/or oral medications to eradicate the source of the infections (often bacteria and/or yeast overgrowth). Dogs may have debris in the ears that must be removed under general anesthesia.
Tumors and cysts are usually diagnosed after advanced imaging like CT or MRI. In some cases, surgery can be done to remove the tumor or cyst. If a cancerous tumor is present, chemotherapy and/or radiation may be recommended.
Prognosis for Dogs With Vestibular Disease
The prognosis for dogs with idiopathic vestibular disease is excellent, as most recover fully within days to months. For dogs with other causes of vestibular dysfunction, the prognosis depends on how well that condition can be treated. Hypothyroidism and ear infections, for example, are easily treated with medications, but dogs with strokes, tumors, or severe trauma have poorer outcomes.
How to Prevent Vestibular Disease
Unfortunately, there is no sure way to prevent vestibular problems in dogs. If your dog is prone to ear infections, then regular ear cleaning with a vet-approved cleanser can help keep ear infections from developing. Annual or biannual veterinary exams and lab tests can help your vet detect subtle changes in your dog's health before your dog develops vestibular dysfunction.
If you notice signs of vestibular disease in your dog, do not wait for it to go away. Bring your dog to the vet as soon as you can. The sooner the underlying cause (if any) is found, the faster your dog can get proper treatment.