Clinical Reasoning: Sudden hearing loss with vertigo in a 42-year-old woman

A 42-year-old previously healthy woman developed sudden right hearing loss, vertigo, and nausea. She had a dull and compressing sensation in the right ear but denied any significant headache or neck pain. She had no medical history including vascular risk factors and neuro-otologic disorders and denied a recent history of head and neck trauma. Review of systems was unremarkable. Neurologic examination showed a small spontaneous downbeat nystagmus only in darkness without visual fixation. The downbeat nystagmus increased after horizontal head-shaking and in the straight-head hanging position. There was neither gaze-evoked nystagmus nor skew deviation. Bedside horizontal head impulse tests (HITs) and other neurologic examinations were also normal. Pure tone audiometry documented a profound sensorineural hearing loss (SNHL) in the right ear with a pure tone average at 100 dB (figure, A). Video-HITs showed normal head impulse gains for all 6 semicircular canals (SCCs) but small covert saccades for right posterior SCC. The results of bithermal caloric tests, cervical and ocular vestibular-evoked myogenic potentials, and measurements of subjective visual vertical were normal. © American Academy of Neurology.