Multiple Sclerosis Presenting as an Anterior Semicircular Canal Benign Paroxysmal Positional Vertigo: Case Report.

We present the case of a 31-year-old woman with isolated symptomatology accusing positional vertigo. The videonystagmography (VNG) including Dix-Hallpike testing we have performed, highlighted atypical eye movements. We have observed a positional downbeating nystagmus with characteristics that could be accounted for anterior semicircular canal benign paroxysmal positional vertigo. Furthermore, examining the atypical nystagmus at the measurements performed during VNG recordings, we suspicioned a central positional vertigo. The abnormalities observed at the positional nystagmus were the lack of latency period, the downbeating component not limited in time, and the atypical torsional component. The magnetic resonance imaging examination recommended showed multiple white matter lesions characteristic for multiple sclerosis. The patient was referred to the neurology department for further evaluation and treatment. The diagnosis was unexpected because the patient did not have any other symptom that could have been linked to multiple sclerosis.