Vestibular neuronitis

Vestibular Neuronitis, also called Vestibular neuritis, can be a paroxysmal, single attack of vertigo, a series of attacks, or a persistent condition which diminishes over two weeks. It may be associated with nausea, vomiting, and previous upper respiratory tract infections. It generally has no auditory symptoms, unlike labyrinthitis. Vestibular neuronitis may also be associated with eye nystagmus. It is caused by inflammation of the vestibular nerve, the nerve that connects the inner ear to the brain.

Diagnosis
In large part, the process involves ascertaining that the entire situation can be explained by a lesion in one or the other vestibular nerve. It is not possible on clinical examination to be absolutely certain that the picture of "vestibular neuritis" is not actually caused by a brainstem or cerebellar stroke, so mistakes are possible. Nevertheless, this happens so rarely that it is not necessary to perform MRI scans or the like very often. Signs of vestibular neuritis include spontaneous nystagmus and unsteadiness. One may notice that vision is disturbed or jumpy on looking to a particular side. This usually means that the opposite ear is affected -- it is called "Alexander's Law" and is due to asymmetric gaze evoked nystagmus. Occasionally other ocular disturbances will occur such as vertical double vision -- skew deviation. However if symptoms persist beyond one month, reoccur periodically, or evolve with time, testing may be proposed. In this situation, nearly all patients will be asked to undergo an audiogram and an ENG. An audiogram is a hearing test needed to distinguish between vestibular neuritis and other possible diagnoses such as Meniere's disease and Migraine. The ENG test is essential to document the characteristic reduced responses to motion of one ear.

Causes
Vestibular Neuronitis is felt to be caused by a viral infection of the balance nerve that runs from the inner ear to the brainches. It is not known which virus in particular causes this problem, and in fact many different viruses may be capable of infecting the balance nerve. Some patients will report having an upper respiratory infection (common cold) or a flu prior to the onset of the symptoms of vestibular neuronitis, others will have no viral symptoms prior to the vertigo attack.

Symptoms
The main symptom of vestibular neuronitis is vertigo, which appears suddenly, often with nausea and vomiting. Vertigo usually lasts for several days or weeks. In rare cases it can take months to go away entirely. Vestibular neuronitis does not lead to loss of hearing.

Treatment
Viral infection of the vestibular nerve and/or labyrinth is believed to be the most common cause of vestibular neuronitis. Acute localized ischemia of these structures also may be an important cause. Especially in children, vestibular neuritis may be preceded by symptoms of a common cold. However, the causative mechanism remains uncertain.