Isolated vestibulocochlear dysfunction of central or peripheral vascular origin

Sudden deafness related to posterior circulation infarction in the territory of the nonanterior inferior cerebellar artery: frequency, origin, and vascular topographical pattern

AIMS

To investigate the frequency and origin of sudden deafness (SD) associated with the nonanterior inferior cerebellar artery (non-AICA) territory posterior circulation infarct(s), and the vascular topographical patterns of ischemic lesion associated with SD.

METHODS

A total of 685 consecutive cases of vertebrobasilar ischemic stroke diagnosed by brain MRI from acute stroke registry were studied.

RESULTS

Seven consecutive patients (1.0%) were identified as having SD as a symptom of non-AICA territory vertebrobasilar ischemic stroke. Audiological testing confirmed sensorineural hearing loss, predominantly cochlear in 4 patients and combined on the affected side cochlear and retrocochlear in 3 patients. Five patients had an isolated cerebellar infarct in the territory of the medial branch of the posterior inferior cerebellar artery and other 2 had infarct in the brainstem. In all, SD was on the side of infarct, as shown on brain MRI. Six patients had accompanied canal paresis to caloric stimulation on the side of SD.

CONCLUSIONS

SD due to non-AICA territory infarction was mostly associated with infarct in the territory of the posterior inferior cerebellar artery. From the known variation of the anatomy of the internal auditory artery and results of audiovestibular evaluations, SD due to non-AICA territory infarct probably results from the damage to the inner ear.

Neuro-otological emergencies

PURPOSE OF THE REVIEW

Physicians find acute vertigo a diagnostic challenge. This article review recent evidence outlining the clinical presentation of acute central and peripheral dizzy syndromes and suggest when clinicians may consider acute neuro-imaging.

RECENT FINDINGS

Recent evidence highlights the difficulty that acute vertigo may sometimes pose to the clinician. For example, migrainous vertigo may have oculomotor abnormalities suggestive of either central neurological or peripheral vestibular dysfunction. Furthermore, vertebrobasilar stroke syndromes may mimic peripheral disorders such as vestibular neuritis, or when there is hearing involvement may be misdiagnosed as Meniere's disease. In addition to the need for identifying serious conditions in acute vertigo, recent evidence suggests that early steroid treatment in vestibular neuritis may improve long term outcome. Further trials regarding symptomatic outcome are required, however, before routine use of steroids can be recommended in this condition.

SUMMARY

Recent findings have not made the assessment of acute vertigo any easier for the nonspecialist. Although the commonest vertigo syndromes are benign, serious conditions such as stroke may masquerade as a peripheral labyrinthine disorder and conversely benign conditions such as migrainous vertigo may have clinical characteristics of central disorders. These findings re-emphasize the need for a thorough clinical evaluation of the acutely dizzy patient.

Sudden deafness in vertebrobasilar ischemia: clinical features, vascular topographical patterns and long-term outcome

BACKGROUND AND PURPOSE

The aim of this study is to document the clinical features and natural history of sudden deafness associated with vertebrobasilar ischemia (VBI) and to describe the vascular topographic patterns of ischemic lesions on brain MRI associated with sudden deafness based on data collected from a prospective acute stroke registry.

METHODS

From 364 consecutive cases of VBI diagnosed by clinical features and brain MRI between January 2000 and September 2003, 29 patients were identified as having sudden deafness as a symptom of VBI.

RESULTS

In our series, the incidence of sudden deafness following VBI is 8.0% (29/364). Hearing loss occurred unilaterally (n=27) or bilaterally (n=2). All but one had vertigo as an associated symptom. Nine patients (31%) presented with an isolated audiovestibular loss initially and subsequently had delayed neurological deficits. Nearly a half of patients (14/29: 48%) showed cochlear features of hearing loss. Seventeen (81%) of 21 patients who were followed for at least 1 year after onset of sudden deafness had a recovery of hearing partially (n=10) or completely (n=7). The improvement rate of hearing loss in patients with profound hearing loss was significantly lower than that in patients with less than profound hearing loss (40% vs. 89%, P<0.01). In addition to infarction in the territory of anterior inferior cerebellar artery (n=23), cerebellar infarction in the territory of the medial branch of posterior inferior cerebellar artery (n=4) or an isolated brainstem infarction (n=2) was also associated with sudden deafness.

CONCLUSION

An isolated sudden deafness with cochlear audiometric features can be the initial presentation of VBI. Sudden deafness due to VBI often has a good outcome. There is topographic heterogeneity of ischemic lesions on brain MRI in patients with sudden deafness due to VBI.