Canine vestibular disease might sound complicated, but it’s relatively common, especially in older dogs. The vestibular system is part of the middle ear that is responsible for coordinating balance, movement, and spatial orientation. The system communicates with nerves, which carry messages to the brain to control the eyes and limbs to allow normal movement without feeling dizzy or unbalanced.
There are many causes of vestibular disease and they are relatively common, especially in older dogs. The diseases may affect any portion of the vestibular system and they are broken down into two general categories, peripheral and central. Peripheral vestibular diseases affect the ear or nerves and central vestibular diseases affect the brain. To diagnose vestibular disease, your veterinarian will first perform a complete physical and neurologic exam. Other tests including blood pressure measurement and blood work. To definitively diagnose the specific cause of vestibular disease, advanced imaging (MRI or CT scan) is often needed. Sometimes veterinarians order a cerebrospinal fluid tap, which collects the fluid around the brain, to also help diagnose the disease.
The clinical signs of vestibular disease include:
- Head tilt (if your dog’s head tilts to the side)
- Ataxia, which means a wobbly gait
- Falling over or circling
- Nystagmus, where the eyes make uncontrolled repetitive movements side to side, up and down, or in a circular pattern
- Additional, non-specific signs including:
- Decreased appetite
- Nausea which generally presents as drooling or constant licking of the lips
The most common type of peripheral vestibular disease is known as idiopathic vestibular disease, also frequently called geriatric or old dog vestibular disease. Idiopathic means the disease may occur acutely and spontaneously, but has no known cause.
There is unfortunately no way to prevent vestibular disease in dogs, and it can be scary for pet owners since the symptoms can present quickly: in an hour or less. Symptoms are usually at their worst for the first one to two days. In most cases, signs spontaneously resolve over several days to a few weeks. The majority of dogs return to normal health over several weeks after the initial onset. Some pets might not completely return to normal, and can have permanent deficits such as head tilt or ataxia.
Other causes of peripheral vestibular symptoms include diseases affecting the ear, such as otitis media or interna (deep ear infections) and benign or cancerous tumors. Tumors can also be present on the nerve that signals to the brain. Hypothyroidism, in which the body does not produce enough thyroid hormone can also affect the vestibular system if left untreated.
The causes of central vestibular disease are often more serious and can be challenging to treat. Central vestibular disease carries a more guarded prognosis due to involvement of the brain tissue, which often leads to significant, permanent vestibular signs.
In an older dog, brain tumors are a common cause. These may be primary tumors originating from the brain which can be benign or cancerous. Cancerous tumors from other organs can also metastasize or spread to the brain, particularly hemangiosarcoma, which often affects the spleen and liver, mammary tumors and melanoma. Tumors that have metastasized carry a poor prognosis, and generally do not respond to treatments such as chemotherapy, surgery, or radiation. Brain hemorrhage, a type of stroke, is also a common cause. This can occur due to hypertension (high blood pressure), infections or issues with clotting blood appropriately. Diseases affecting the immune system and infections may cause meningoencpehalitis, which is inflammation of the brain and the surrounding protective tissues. Infectious causes include viruses such as distemper, parasites, bacteria or fungus.
Some diseases may affect both the peripheral and central vestibular system. These include head trauma and birth defects.
Unfortunately, most types of vestibular diseases are not preventable. Infectious causes are preventable by keeping dogs up to date on their vaccines, and using year-round heartworm and tick treatments. Internal ear infections may be preventable by keeping the environment of your dog’s external ear clean and by monitoring for early signs of ear infections, such as head shaking and excessive scratching.
Fish oil supplements may help as a natural anti-inflammatory in decreasing the severity and frequency of ear infections. For dogs who have ataxia permanently, fish oil and joint supplements containing glucosamine, chondroitin and MSM may help improve mobility and prevent conditions such as arthritis from occurring due to an abnormal gait.
Treatment varies significantly depending on the specific cause. Idiopathic vestibular disease has no specific treatment other than supportive care. No matter the cause, it is critical to keep the dog safe and rested to prevent injury. Some pets will need to be hand fed or have the water bowl lifted for them. Antinausea and motion sickness medication is sometimes also helpful. For pets that are severely affected, hospitalization may be necessary. If your dog exhibits any of the above symptoms, it’s wise to call your veterinarian immediately.
Sources: Brooks, Wendy. “Vestibular Disease in Dogs and Cats”. Veterinary Information Network, 1 Jan. 2001.
Lowrie M: Vestibular disease: anatomy, physiology, and clinical signs. Compend Contin Educ Vet 2012 Vol 34 (7) pp. E1.
Moriello, Karen A., and By. “Otitis Media and Interna in Dogs.” Otitis Media and Interna in Dogs , Merck Veterinary Manual, June 2018.
Rossmeisl JH: Vestibular disease in dogs and cats. Vet Clin North Am Small Anim Pract 2010 Vol 40 (1) pp. 81-100.
“VH-Small Animal: Neurology Brain Tumors in Dogs and Cats.” NC State Veterinary Medicine, 13 Sept. 2019.