Vestibular neuritis

Vestibular neuritis, also known as acute unilateral vestibulopathy (AUVP) or vestibular neuronitis, refers to presumed inflammation of the vestibular nerve/vestibulocochlear nerve. It can be associated with labyrinthitis.

The vestibular nerve is a large division of cranial nerve eight (CN VIII) that transfers the equilibrium information from the inner ear to the central nervous system. The cochlear nerve is the other large branch of the vestibulocochlear nerve that transports the sounds findings to the central nervous system. Inflammation of the vestibular branch of CN VIII (vestibulitis) is associated with the vertigo symptoms.

On the other hand, swelling of both vestibular and cochlear nerve bundles (labyrinthitis) produce tinnitus and/or hearing problems moreover to vertigo.

Epidemiology

Some consider this being the third most common cause of peripheral vestibular vertigo. It has an estimated annual incidence of 3.5 per 100,000 population and may account for 7% of patients at outpatient clinics specializing in the treatment of vertigo ⁷. Vestibular neuritis is common between men and women aged 30-60 years old ^1,2.

Clinical presentation

Some patients may give a history of a prodromal gastrointestinal or upper respiratory tract infection, especially in men and women aged 30-60 years old ^1,2.

Otherwise, the syndrome presents typically ²:

• vertigo, sudden and severe

• spontaneous horizontal nystagmus, whereby the fast phase beats away from the affected side (Alexander's law)

• balance/gait difficulty

• nausea and vomiting

• concentration problems

After recovery of the symptoms, balance and dizziness disorders can last for several months in some patients.

Pathology

Preferentially, the superior division of the vestibular nerve is affected, which leads to involvement of the superior and horizontal semicircular canals, however, both divisions can also be affected concurrently ⁷. Viral infections are thought to be the commonest causes of the vestibular neuritis, with bacterial infections being much less common. Most common viral causes of vestibular neuritis include herpes simplex virus (HSV-1) (considered the most common viral etiology ²), measles, rubella, mumps, Epstein-Barr virus, influenza, and varicella/herpes zoster.

Radiographic features

MRI

MRI with contrast is sometimes requested in order to exclude other causes of sudden onset dizziness and vertigo such as stroke (especially AICA territory strokes) and brain tumors, especially in the elderly. However, typically the MRI is normal in vestibular neuritis.

• T1 C+ (Gd): can show enhancement of the vestibular nerve fibers within the internal auditory canal with the labyrinth of the inner ear often intact

Treatment and prognosis

Corticosteroids, antiemetics and vestibular physiotherapy are standard supportive measures of care ². No antiviral or antibacterial therapy is usually necessary. Recurrence is rare and most patients will show full recovery.

Differential diagnosis

• AICA territory ischemic stroke

• isolated nodular ischemic stroke ³

• anti-GQ1b antibody syndrome ⁸