Embolic internal auditory artery infarction from vertebral artery dissection.

A 51-year-old man developed sudden vertigo, right hearing loss and dysphagia. Examination revealed right Horner syndrome, spontaneous torsional-horizontal nystagmus, right central type facial palsy, dysarthria, reduced soft palate elevation without gag reflex, left hypesthesia, right dysmetria and imbalance. Audiometry and bithermal caloric tests documented right sensorineural hearing loss and canal paresis. Brain MRI and cerebral angiography documented right lateral medullary infarction from vertebral artery dissection, without involvement of other parts of the brainstem supplied by the anterior inferior cerebellar artery (AICA). This case suggests artery-to-artery embolism as a possible mechanism of isolated vertigo or hearing loss from labyrinthine infarction.