Abstract
Vestibular neuritis is the most common cause of acute spontaneous vertigo. Vestibular
neuritis is ascribed to acute unilateral loss of vestibular function, probably due
to reactivation of herpes simplex virus in the vestibular ganglia. The diagnostic
hallmarks of vestibular neuritis are spontaneous horizontal-torsional nystagmus beating
away from the lesion side, abnormal head impulse test for the involved semicircular
canals, ipsilesional caloric paresis, decreased responses of vestibular-evoked myogenic
potentials during stimulation of the affected ear, and unsteadiness with a falling
tendency toward the lesion side. Vestibular neuritis preferentially involves the superior
vestibular labyrinth and its afferents. Accordingly, the function of the posterior
semicircular canal and saccule, which constitute the inferior vestibular labyrinth,
is mostly spared in vestibular neuritis. However, because the rare subtype of inferior
vestibular neuritis lacks the typical features of vestibular neuritis, it may be misdiagnosed
as a central vestibular disorder. Even in the patient with the typical pattern of
spontaneous nystagmus observed in vestibular neuritis, brain imaging is indicated
when the patient has unprecedented headache, negative head impulse test, severe unsteadiness,
or no recovery within 1 to 2 days. Symptomatic medication is indicated only during
the acute phase to relieve the vertigo and nausea/vomiting. Vestibular rehabilitation
hastens the recovery. The efficacy of topical and systemic steroids requires further
validation.
Keywords
vestibular neuritis - vertigo - nystagmus - head impulse test - vestibular evoked
myogenic potential
