Idiopathic Vestibular Syndrome….What Is It And Why Does It Happen?
The vestibular system has two main parts in the body; the peripheral part (structures within the inner ear) and the central part (nuclei and nerves within the brain). The two act together to maintain balance and orientation in respect to gravity. Dysfunction in either part of the system therefore leads to disorientation and a lack of awareness in body position.
Vestibular syndrome is a term used to describe the collection of clinical signs that we see when the vestibular system is affected. They include:
- A head tilt to one side
- Falling leaning, circling or rolling to the side
- Abnormal movement of the eyes referred to as ‘nystagmus’
- Abnormal position of the eyes referred to as ‘strabismus’
- Vomiting and anorexia due to feelings of nausea from the lack of orientation
- Wobbliness in all four legs and/or a wide based stance
It can often appear quiet scary when your pet starts displaying these signs and most people wonder if there pet has had a seizure or a stroke. Vestibular disease can in fact be due to a number of reasons. There are specific causes which affect the peripheral system (middle/inner ear infection, trauma, toxicity or tumours, nasopharyngeal polyps and hypothyroidism) and the central system (degenerative disease, cysts or structural issues, thiamine deficiency, brain tumours, meningiocephalitis, drug toxicity, head trauma and vascular disease.)
However, one of the most common presentations that we see is a type of peripheral vestibular disease called ‘idiopathic’ This means we don’t really know or are unable to identify the true reason for it’s occurrence. The redeeming quality however is that it is usually a self resolving condition with a good prognosis. If we feel idiopathic vestibular syndrome is the most likely differential diagnosis then our therapy is aimed at managing the clinical signs and symptoms until it resolves.
To be certain of course we would have to rule out all of the other causes above with full investigations. This can involve blood tests, an MRI of the brain/spine and even sampling some of the spinal fluid. This is so we don’t miss another condition which would require a much different treatment or which might hold a much different prognosis. However, this isn’t always an option and I’m sure you can appreciate this is is potentially a lot of investigations to prove that nothing can be identified. As a large proportion of dogs are in fact ‘idiopathic’ it can very reasonable to try supportive care first.
This includes anti-sickness medications which should hopefully stop the vomiting, reduce nausea and encourage your pet to eat. Your pet then requires nursing care; this includes a safe area with lots of padding, regular re-positioning to maintain comfort and prevent secondary issues. Your pet will also need help and support whilst taking out to toilet. Some of this is manageable at home but in some cases hospitalisation is recommended.
Resolution of signs can take days to weeks but as long as we are seeing an improvement in these signs this is acceptable. Some dogs can in fact be left with a residual head tilt but this rarely affects their quality of life or day to day activities afterwards. Unfortunately, failure to respond to normal management or recurrent episodes of vestibular disease can point towards another underlying reason and at this point further work up is necessary.