Acute Vestibular Syndrome Following Anterior Inferior Cerebellar Artery (AICA) Occlusion

An ischemic posterior circulation stroke in the territory of the anterior inferior cerebellar artery (AICA) is the leading cause of acute audiovestibular loss. Approximately 10% of ischaemic strokes in the territory of AICA show audio-vestibular symptoms in isolation and patients may have normal brain imaging on initial presentation. Up to 30% of these might be a prodromal event in the previous 10 days. This is due to the blood supply to the labyrinth depending on the Internal Auditory Artery (IAA), a branch of the AICA. These symptoms are more commonly associated with benign peripheral (inner ear) pathology. Strokes that present in this way, particularly the ischaemic strokes in the territory of AICA, might be missed, which represents a diagnostic pitfall. Herein, we report the case of a 73-year-old man presenting with abrupt-onset vertigo and hearing loss due to AICA occlusion. We subsequently discuss the salient clinical characteristics of AICA strokes and its anatomo-functional basis. Brain imaging is often unhelpful in demonstrating early ischemic changes in the posterior fossa and/or selective ischemia of the labyrinth. Audiovestibular investigations may show a peripheral origin. Thus, diagnosis usually relies on key clinical findings in abrupt stroke-like onset in a patient with vascular risk factors, subtle signs of CNS involvement, and the presence of both vestibular and cochlear symptoms.