By Dr. Danielle Huval
An older dog with a sudden head tilt, lack of coordination (ataxia), and eyes that are moving rapidly from side to side or rotationally (nystagmus) may have vestibular disease. Vestibular disease occurs when the vestibular apparatus, a region in the ear that helps the body balance and orient to the environment, is not functioning correctly. This can be caused by a middle ear infection, a brain lesion, or is unknown (idiopathic). Other signs include motion sickness (vomiting), circling, and falling to one side. Some dogs can be unable to walk or get up without help. The good news is that idiopathic vestibular disease usually resolves completely within weeks and improves dramatically within the first 24-48 hours.
While it is not always possible to determine the exact cause of vestibular disease, it is important to note that this is not a stroke (vascular accident). A vascular accident is defined as an injury or death of neurons (cells in the brain) caused by a lack of blood supply. This does occur in dogs but is very rare because dogs do not have vascular disease (clogged arteries), which is common in humans. A vascular accident can cause a number of different symptoms all depending on what area of the brain has been affected. Common stroke associated symptoms include collapse or weakness, decrease in mental alertness, change in position of eyes, and even seizures.
In an initial exam of a dog with vestibular disease, it may be possible to determine whether the symptoms are being caused by a middle ear infection. Histories that include ear infections, a concurrent outer ear infection, or facial nerve paralysis, are signs that the vestibular symptoms are related to a middle ear problem. However, sometimes the outer canal of an ear looks normal and radiographs, CT or MRI may be necessary to fully evaluate and determine if a middle ear is involved. Treatment of a middle ear infection starts with long-term antibiotics. Bacterial cultures and procedures that are more involved may be necessary if the ear infection does not improve.
If vestibular signs are noted with other nerve deficits, the eyes move up and down rapidly (vertical nystagmus) or the nystagmus is positional or changing, this may indicate a brain lesion. Causes of a brain lesion include a brain tumor, infection, or vascular accident. A CT scan or MRI is often needed to more completely diagnose what kind of lesion is affecting the brain. Treatments of brain lesions are mostly supportive, but may include seizure medications, long-term hospitalization, and intensive care. This type of vestibular disease has a guarded prognosis, generally worse outcome, than other causes.
Idiopathic vestibular disease, or old dog vestibular disease, is the most common cause of vestibular disease in dogs. Although we do not know the cause of this disease, symptoms usually improve within 24-48 hours. Vestibular disease symptoms occur quite rapidly and can be very scary. Generally, a dog having a vestibular episode is extremely stressed and their needs cannot be met at home. Treatment may be necessary to control vomiting and to keep them from becoming dehydrated. This often involves short-term hospitalization and IV fluids. With vestibular disease, a dog may not be able to stand or walk and caring for a large dog suffering from this disease can be very difficult. Within a couple of weeks, most dogs will have fully recovered, although some dogs may have a lasting head tilt or ataxia.
If at any time your dog is uncoordinated, cannot get up, or collapses, this is an emergency! While it may be idiopathic vestibular disease, many other diseases can mimic these signs and immediate treatment could be lifesaving. A veterinarian should evaluate him or her as soon as possible. Figuring out what is going on will help you make a decision for what is best for your pet and the rest of the family as soon as possible. So if there is any doubt, call us or bring your pet to your veterinarian or an emergency clinic after hours. We are here to help.
AMVS is a 24-hour veterinary facility providing specialty internal medicine, surgery, emergency and critical care, physical rehabilitation, pain management, and blood bank services for pets. They are located in Longmont at 104 S. Main St. For more information, go to www.AspenMeadowVet.com.