A 45-year-old man complains of decreased hearing on the right side for the last 2 months. He also has occasional ringing in the right ear. He has a remote history of early-stage melanoma treated with surgical excision. The patient's medications include metformin for type 2 diabetes mellitus, lansoprazole for gastroesophageal reflux disease, meclizine for intermittent vertigo, and naproxen for occasional low back pain. He is a lifetime nonsmoker.
His blood pressure is 135/85 mm Hg and pulse is 80/min and regular. His body mass index is 30 kg/m². Weber test shows the sound from the tuning fork placed on the patient's forehead localizing to the left side. Rinne test shows air conduction better than bone conduction on both sides.
Which of the following is the most likely diagnosis in this patient?

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Quizplus · Accepted Answer

11ec193a_988e_8f8e_853d_f1b3e63257cb_MD0002_00 This patient's normal Rinne test and Weber test lateralizing to the left ear suggest right sensorineural hearing loss. Causes of sensorineural hearing loss include vestibular schwannoma (acoustic neuroma), presbycusis, Meniere's disease, and ototoxic drugs. Vestibular schwannoma is the most common tumor causing sensorineural hearing loss. It is a benign extra-axial tumor originating from the Schwann cells surrounding the vestibulocochlear nerve. Patients typically present with chronic ipsilateral tinnitus, ipsilateral sensorineural hearing loss, vertigo, nausea/vomiting, horizontal nystagmus, and problems with balance. Diagnosis is confirmed by audiometry documenting hearing loss and visualizing the tumor on brain imaging (eg, magnetic resonance imaging with gadolinium) with detailed views of the vestibulocochlear nerve. Treatment is usually surgical, with favorable long-term outcomes in patients who have complete excision of the lesion. (Choice A) Acute labyrinthitis typically presents with abrupt onset of severe peripheral-type vertigo, nausea, vomiting, gait instability, and unilateral hearing loss. However, symptoms usually peak within 1-2 days, with gradual improvement over the next few days. This patient's chronic symptoms make labyrinthitis unlikely. (Choice B) Cerebellar stroke usually presents with acute-onset vertigo, nausea, vomiting, and/or ataxia. Patients also can have nystagmus toward the side of the lesion. However, hearing is generally preserved. (Choice C) Conversion disorders can present with neurologic symptoms (eg, weakness, abnormal movements, seizure-like movements) that are not consistent with a specific neurologic disease. Conversion disorders are usually considered after other medical or neurologic etiologies are excluded. This patient's objective findings are consistent with a vestibular nerve lesion, making conversion disorder less likely. (Choice D) Otosclerosis is due to bony overgrowth involving the auditory ossicles of the middle ear. Patients typically present with conductive pattern hearing loss (not sensorineural as seen in this patient). Educational objective: Vestibular schwannoma originates from the Schwann cells surrounding the vestibulocochlear nerve and is the most common tumor causing sensorineural hearing loss. Patients typically present with chronic ipsilateral tinnitus, ipsilateral sensorineural hearing loss, vertigo, nausea/vomiting, and problems with balance. __________ References: Diagnosis and therapy of vestibular schwannoma. (http://www.ncbi.nlm.nih.gov/pubmed/19673609)

A 45-Year-Old Man Complains of Decreased Hearing on the Right