Bilateral Sudden Deafness as a Prodrome of Anterior Inferior Cerebellar Artery Infarction

Abstract

Background Acute ischemic stroke in the distribution of the anterior inferior cerebellar artery is known to be associated with hearing loss, facial weakness, ataxia, nystagmus, and hypalgesia. There have been few reports on bilateral deafness and vertebrobasilar occlusive disease. Furthermore, previous reports have not emphasized the inner ear as a localization of bilateral deafness.

Objective To describe the presentation of acute ischemic stroke in the distribution of the anterior inferior cerebellar artery as sudden bilateral hearing loss with minimal associated signs.

Design and Setting Case report and tertiary care hospital.

Patient A 66-year-old man with diabetes mellitus developed sudden bilateral deafness, unilateral tinnitus, and vertigo 7 days before the onset of dysarthria, facial weakness, and ataxia. T2-weighted magnetic resonance imaging scans showed hyperintensities in the right lateral pons and right middle cerebral peduncle and a possible abnormality of the left middle cerebellar peduncle. A magnetic resonance angiogram showed moderately severe stenosis of the distal vertebral artery and middle third of the basilar artery. The patient's right limb coordination and gait improved steadily over several weeks, but there was no improvement in hearing in his right ear.

Conclusions The relatively isolated onset of deafness as well as the severity and persistence of the hearing loss led us to conclude that the hearing loss in this case was likely due to prominent hypoperfusion of the internal auditory artery, with labyrinthine infarction as the earliest event. Vertebrobasilar occlusive disease should be considered in the differential diagnosis of sudden bilateral deafness.

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SUDDEN DEAFNESS may be defined as more than 20 dB of sensorineural hearing loss occurring over minutes to hours.1 Sudden deafness occurs unilaterally in most cases, and bilateral, simultaneous, sudden deafness is a rare condition, accounting for 0.44% to 3.4%2,3 of cases of sudden deafness. Unilateral, sudden deafness in a young patient is usually idiopathic and is often thought to be viral4,5or autoimmune6 in origin. On the other hand, sudden deafness in an older patient with known cerebrovascular occlusive disease suggests the likelihood of ischemia in the distribution of the internal auditory artery, ordinarily a branch of the anterior inferior cerebellar artery (AICA).7- 10 Characteristically, sudden bilateral deafness due to AICA ischemia is associated with multiple brainstem signs.11,12 The AICA supplies the dorsolateral pons, middle cerebellar peduncle, inner ear, and anterior inferior cerebellum, including the flocculus.13,14 Infrequently, infarction of the AICA territory is preceded by isolated episodes of vertigo or unilateral hearing loss.7- 10 There have been few reports on bilateral deafness and vertebrobasilar occlusive disease.11,12,15,16 Furthermore, previous reports have not emphasized the inner ear as a localization of bilateral deafness.11,12,15,16 We describe a patient with AICA infarction who presented with isolated sudden bilateral deafness as the initial symptom.