Isolated labyrinthine infarction as a harbinger of anterior inferior cerebellar artery territory infarction with normal diffusion-weighted brain MRI

Objectives: This paper aims to determine the frequency of isolated labyrinthine infarction as an initial manifestation of anterior inferior cerebellar artery (AICA) territory infarction and discuss its clinical implication. Methods: We studied 54 consecutive patients with AICA infarction diagnosed by brain MRI from the acute stroke registry. Results: We identified 4 patients (7.4%) with AICA territory infarction who initially presented with vertigo and hearing loss mimicking acute labyrinthitis and subsequently suffered from delayed neurological deficits. All patients had normal brain MRIs including diffusion-weighted images at the time of isolated audiovestibular loss, but all subsequently exhibited acute infarct(s) in the AICA territory on follow-up brain MRIs when they developed additional neurological deficits. Conclusion: Labyrinthine infarction may be a warning sign of impending pontocerebellar infarction in the AICA territory. Our results indicate that even a classical peripheral presentation, e.g., acute hearing loss, and acute vertigo with unidirectional nystagmus, may be a manifestation of ischemic stroke in the posterior circulation.