Isolated Labyrinthine Infarction as a Harbinger of Anterior Inferior Cerebellar Artery Territory Infarction
When vertigo or hearing loss is associated with other brainstem or cerebellar signs, the diagnosis of anterior inferior cerebellar artery infarction is easily made. However, partial ischemia of the anterior inferior cerebellar artery may give rise to isolated vertigo or hearing loss because the internal auditory artery is an end artery with minimal collaterals from other major arterial branches, and the cochlea and vestibular apparatus are supplied by different branches of the internal auditory artery.[4–6]
There have been several case reports indicating that labyrinthine infarction may be an impending sign of anterior inferior cerebellar artery territory infarction.[9,10,31,32] In one recent study, 8% (4/43) of patients with documented anterior inferior cerebellar artery territory infarction on brain MRI initially experienced an isolated audiovestibular symptom (i.e., sudden onset of vertigo and/or hearing loss) with a normal MRI. Clinicians should consider a posterior circulation stroke when caring for a patient with an acute peripheral-type audiovestibular syndrome, especially if the patient has vascular risk factors and vertebrobasilar compromise on brain magnetic resonance angiography (MRA).
Vestibular function testing interpreted as "peripheral—no signs of central nervous system involvement" does not rule out vertebrobasilar ischemic stroke. On the other hand, a normal MRI does not rule out a vascular (i.e., labyrinthine infarction) etiology.
Fig. 5 illustrates the MRI findings in a patient with acute audiovestibular loss as a prodromal sign of anterior inferior cerebellar artery territory infarction. The diffusion-weighted MRI was normal at the time of acute isolated audiovestibular loss. The site of injury responsible for isolated audiovestibular loss was probably localized to the inner ear or vestibular nerve.
Magnetic resonance imaging (MRI) findings in a patient with acute audiovestibular loss as a prodromal sign of anterior inferior cerebellar artery territory infarction. (A,B) Axial diffusion-weighted brain MRI performed one day after the onset of sudden hearing loss and vertigo was normal. Two days later, (C,D) axial diffusion-weighted MRI scans demonstrated hyperintense foci involving the left middle cerebellar peduncle, left dorsolateral pons, and the left anterior cerebellum.
Semin Neurol. 2009;29(5):534-540. © 2009 Thieme Medical Publishers
Cite this: Inner Ear Dysfunction Due to Vertebrobasilar Ischemic Stroke - Medscape - Nov 01, 2009.