Synonym: vestibular neuronitis

Strictly speaking the term means inflammation of the vestibular nerve but the aetiology is thought to be a vestibular neuropathy. In a significant proportion of cases, the cause is thought to be a reactivation of herpes simplex virus that affects the vestibular ganglion, vestibular nerve, labyrinth, or a combination of these.^1,2 There is sudden disruption of afferent neural input so that acute vertigo results.

Epidemiology

There is no gender predominance and the mean age of onset is 41 years.² The incidence has been quoted as 170 cases per 100,000.³

Presentation^2,3,4

History

• Onset is usually very abrupt.
• There is unsteadiness, nausea and vomiting.
• They feel as if the room is rotating.
• Moving the head aggravates symptoms.
• Distinguish between true rotational vertigo and giddiness, faintness or weakness. Patients are often very vague in the terms they use and may attempt medical terminology but get it wrong.

Examination

• Spontaneous, unidirectional, horizontal nystagmus is characteristic.The fast direction is towards the healthy ear. The fast direction may be the more obvious but it is really the correction of the pathological slow direction.
• Nystagmus may be apparent only on gazing away from the affected side or it may be suppressed by optic fixation.
• On walking or during the Romberg's test, the patient tends to fall towards the affected side.

The following should be sought as their presence suggests that it is not vestibular neuritis:

• Nystagmus is multidirectional and does not fatigue on repetitive testing.
• Hearing loss.
• Abnormalities of cranial nerves other than VIII.
• Red tympanic membrane.
• Cerebellar ataxia.
• Mastoid tenderness, nuchal rigidity or high fever.

If it was not possible to demonstrate the vertigo the Hallpike manoeuvre may be employed (although provocative tests such as these will be unpleasant for the patient and so may not be appropriate):⁵

• Get the patient to sit on the couch with the head end flat.
• The patient should lie back from sitting to supine 3 times. The first time the head faces forward with the neck slightly extended. The second time the head is turned 45º to one side and the third time to the other side.
• The patient should keep both eyes open all the time. Each time check for signs of nystagmus and ask about feelings of vertigo.

There is usually a slight latent period of just seconds between the manoeuvre and the onset of symptoms and signs. There is also a tendency for them to fatigue with repeated testing. If these features are not present it suggests that the aetiology might be central, in the brain, rather than peripheral in the vestibular apparatus.

Another helpful test to differentiate vestibular neuritis from stroke is the head impulse test. The patient is asked to fix their gaze on a point and the head is rapidly rotated. If the eyes do a corrective shift once the head stops moving rather than maintaining contact throughout the movement, this is deemed suggestive of a vestibular disorder.²

Investigations²

• The diagnosis can usually be made clinically and blood tests are usually unhelpful.
• Imaging studies (e.g. brain MRI or CT scanning) may demonstrate tumours, haemorrhage or ischaemic stroke or demyelination. Imaging tends to be reserved for cases where more sinister pathology is suspected.

Differential diagnosis²

• Benign positional vertigo.
• Labyrinthitis.
• Ménière's disease.
• Stroke, especially posterior inferior cerebellar artery syndrome (central signs not always present so stroke should be considered in any patient with cardiovascular risk factors).¹
• Multiple sclerosis.
• Subarachnoid haemorrhage.
• Tumours of the brain or acoustic neuroma.
• Cervical spondylosis.

Management^2,3

• If the patient has marked vertigo with vomiting, an antiemetic is useful and it may suppress the vertigo too. Nausea will retard gastric emptying and it may reverse and so an injection may be required.
• A vestibular suppressant such as prochlorperazine may be useful but should be stopped within a few days of onset as prolonged use may impede the process of central vestibular compensation.
• If the patient has recurrent attacks and needs self-administered medication, buccal prochlorperazine may be appropriate.
• Promethazine and domperidone may be useful.
• The speed of recovery can be improved by use of steroids but a recent trial of prednisone failed to demonstrate any effect on long-term prognosis.^6,7 It is reasonable to treat otherwise healthy individuals within three days of onset but withhold steroids from patients who are more likely to suffer from the risks than gain from the benefits.¹
• Antiviral agents do not appear to help, either alone or with steroids.⁸
• Early activity should be encouraged to promote vestibular compensation.
• A Cochrane review found low-quality evidence that vestibular rehabilitation (exercises to promote central nervous system compensation) was effective in reducing dizziness in vestibular neuritis.⁹

Prognosis

One study found that recovery rate of peripheral vestibular function lies between 40-63% depending on early-onset treatment with corticosteroids; the recurrence rate within 10 years was 2%.¹⁰ Another study found a persistence of dizziness related to anxiety in one third of patients one year after the initial episode.¹¹

Document references

1. Walker MF; Treatment of vestibular neuritis. Curr Treat Options Neurol. 2009 Jan;11(1):41-5. [abstract]
2. Marill K; Vestibular neuronitis, eMedicine, Nov 2009
3. Samy H; Dizziness, Vertigo, and Imbalance, eMedicine, Jan 2010
4. Shaia W, Inner Ear, Evaluation of Dizziness, eMedicine, May 2010
5. Labuguen R; Initial Evaluation of Vertigo American Family Physician 2006, January:244
6. Strupp M, Brand T; Pharmacological advances in the treatment of neuro-otological and eye movement disorders. Curr Opin Neurol. 2006 Feb;19(1):33-40.
7. Shupak A, Issa A, Golz A, et al; Prednisone Treatment for Vestibular Neuritis. Otol Neurotol. 2008 Feb 28;. [abstract]
8. Sullivan FM, Swan IR, Donnan PT, et al; Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med. 2007 Oct 18;357(16):1598-607. [abstract]
9. Vertigo, Clinical Knowledge Summaries (April 2010)
10. Brandt T, Huppert T, Hufner K, et al; Long-term course and relapses of vestibular and balance disorders. Restor Neurol Neurosci. 2010;28(1):69-82. [abstract]
11. Neuhauser HK; Epidemiology of vertigo. Curr Opin Neurol. 2007 Feb;20(1):40-6. [abstract]

Acknowledgements