Objective: To explore the clinical characteristics and possible pathological mechanisms of vertigo due to enlarged vestibule with lateral semicircular canal dysplasia.
Methods: A retrospective review was conducted for 5 cases of peripheral vertigo due to enlarged vestibule with lateral semicircular canal dysplasia. Their characteristics of medical history, precipitating factors, course of vertigo, auditory tests, vestibular tests and imaging examine results were analyzed.
Results: The clinical characteristics were as follows. (1) Specifics of medical history: 4 cases suffered delays in gross motor development and potential equilibrium dysfunctions. One case failed to recount an earlier medical history, but could maintain normal hearing and vestibular functions for a long time in adulthood. (2) Most cases could identify the precipitating factors of initial attacks, such as head-bumping, nose-blowing and constipation, etc. resulting in sudden rises of intracranial or abdominal pressures. (3) Paroxysmal vertigo and progressive hearing loss were mimicking Meniere disease or large vestibular aqueduct syndrome. But its course of vertigo was different from those of Meniere disease and large vestibular aqueduct syndrome with regards to hearing levels and audiograms. (4) Some cases had positional vertigo. But the results of Dix-Hallpike and Roll tests were different from benign paroxysmal positioning vertigo (BPPV). (5) The inner ear imaging showed enlarged vestibule with lateral semicircular canal dysplasia.
Conclusion: The enlarged vestibule with lateral semicircular canal dysplasia is a rare etiology of peripheral vertigo. The history of delays in gross motor development and potential equilibrium dysfunctions in childhood may offer important diagnostic clues. And audiological and vestibular tests, high-resolution computed tomography and magnetic resonance may help to ascertain the diagnosis.