Canine Vestibular Disease

Canine vestibular disease (CVD) can be peripheral (e.g. an ear infection) or central (a brain defect), but the symptoms are very similar.

Your dog may have a head tilt to one side, their eyes may flick sideways, and they are often uncoordinated or wobbly. Understandably many owners think their dog has had a stroke. The sideways movement of the eyes is called nystagmus and the presence of this means your dog definitely has a problem with their vestibular system. Peripheral VD is due to an issue with the middle or inner ear or the vestibular nerve (the nerve that sends information from the ear to the brain).

Dogs with PVD may have an obvious ear infection on examination, but if the infection is only in the inner ear, then this is much harder to identify as it is beyond the ear drum. Dogs with PVD are usually bright, they may be wobbly due to a loss of balance, but they still have good reflexes, so they don’t knuckle or drag their legs. They may have a high temperature if the ear infection is severe. They can also display Horner’s Syndrome (similar to Bell’s palsy in humans) where one side of the face is paralysed- half the face will be droopy; the eyelid won’t blink and often the dog’s pupils will be different sizes. A thorough ear examination with an otoscope is required- if a medial or inner ear infection is suspected this is treated with antibiotics and anti-inflammatory drugs to reduce a high temperature and help pain.

The most common type of PVD is idiopathic or geriatric. PVD tends to be acute so it starts suddenly and in the case of an ear infection it will be progressive, so it starts mildly and becomes more severe with time. There are usually signs of ear disease and response to antibiotics is rapid. Vestibular syndrome is also acute but is severe at the outset and improves without treatment over a few days. It is mostly seen in older dogs over 8 years old whereas PVD due to an ear infection can be at any age. There is a medication which can be prescribed to aid recovery and help prevent recurrence.

Central VD occurs when there is a lesion in the brainstem, or a part of the brain called the cerebellum. CVD differs from PVD as the dog maybe wobblier, be depressed, have poor reflexes (paralysis of legs - they drag the leg rather than pick it up ). Head tremors are common, but Horner’s Syndrome is not seen.

CVD is much less common than PVD and carries a more grave prognosis. It has several causes including brain inflammation- a disease called Meningoencephalitis. This is associated with a rapid deterioration- it is diagnosed with a brain scan and treated with anti-inflammatory drugs.

CVD could be due to a brain tumour - these cases are more common in older dogs and tend to be slowly progressive, they are diagnosed with a scan and are rarely treatable. CVD can also be caused by an interruption of the blood supply similar to a stroke in humans. It is quite rare in dogs and is usually associated with an underlying condition. Toxins can also result in CVD - the most common one seen is when a dog receives too much of a commonly used antibiotic called metronidazole. Only high doses result in symptoms and signs usually reverse once treatment with metronidazole is stopped.

If your dog shows signs of vestibular disease prompt attention from a vet is vital to ensure the condition is diagnosed correctly and treated accordingly.