Vestibular schwannoma presenting with Valsalva maneuver-induced nystagmus

Excerpt

A 45-year-old male presented with a 1-year history of progressive right ear hearing loss and intermittent tinnitus provoked by exertion or loud noise. He also reported feeling fullness in his right ear and imbalance in the past month. Episodes of vertigo and presyncope following the Valsalva maneuver or ejaculation were reported in the previous year, but he never lost consciousness. On examination, right hypoacusia was present and the rest of the neurological examination was normal. There was no spontaneous, gaze-evoked, positional or hyperventilation-induced nystagmus and the head shaking and head impulse tests were normal. Audiometry verified right sensorineural hearing loss. Caloric testing showed a decreased response of the right labyrinth. Brainstem auditory evoked potentials showed absent response on the right ear with normal waveform responses on the left ear. Vestibular-evoked myogenic potentials (VEMP) revealed the normal cervical and absent ocular VEMPs. A computed tomography scan of the right labyrinth showed no sign of semicircular canal dehiscence. Magnetic resonance imaging of the brain revealed a 10-mm wide vestibular schwannoma, located in the lateral part of the right internal acoustic meatus, pressed into the basal turn of the cochlea (Fig. 1). Testing of cardiovascular autonomic reflexes and head-up tilt table test were normal. Right horizontal nystagmus with a torsional component following the Valsalva maneuver was documented (Video 1).

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