This patient has vestibular neuronitis, which is manifested by acute, severe, and persistent nonpositional peripheral vertigo. Vestibular neuronitis may follow a viral upper respiratory tract infection and is thought to be caused by postviral inflammation of the vestibular portion of cranial nerve VIII. Symptoms may be severe and prolonged. Nausea and vomiting are common. When the Dix-Hallpike maneuver is performed on this patient, the results are consistent with peripheral vertigo, with nystagmus that is provoked after a brief latency period and is relatively severe and short in duration (<1 minute).

Benign paroxysmal positional vertigo (BPPV), the most common cause of vertigo, is classically precipitated by head movement and is caused by otoliths that perturb the labyrinthian sensory receptors. In a patient with BPPV, episodes of vertigo generally last less than 1 minute.

Brainstem infarction or hemorrhage as well as cerebellar infarction or hemorrhage cause vertigo of central origin. In central vertigo, there is no latency in the occurrence of nystagmus with the Dix-Hallpike maneuver. Compared with the findings in a patient with peripheral vertigo, the nystagmus generally lasts longer than 1 minute and symptoms are less severe. Based on the history and physical examination, this patient's presentation is inconsistent with brainstem infarction.

Labyrinthitis is similar to vestibular neuronitis in etiology and presentation except that in labyrinthitis patients exhibit hearing loss. Hearing is preserved in this patient, making labyrinthitis an unlikely diagnosis.