A 52-year-old man comes to the office for evaluation of hearing loss in the left ear. The patient works in sales and is frequently on the phone. Over the past several months, he has had difficulty hearing phone conversations in the left ear and must move the headset to the right. He has no pain or vertigo but sometimes feels off-balance when walking at night and holds onto walls. Vital signs are within normal limits. Physical examination reveals normal tympanic membranes with no middle ear effusion on either side. A tuning fork placed on the forehead is heard best in the right ear. Air conduction is greater than bone conduction bilaterally. There is decreased sensation to touch on the left side of the face. Bilateral upper and lower extremity strength, deep tendon reflexes, and sensation are normal. Which of the following is the most likely cause of this patient's symptoms?

Question

A 52-year-old man comes to the office for evaluation of hearing loss in the left ear.  The patient works in sales and is frequently on the phone.  Over the past several months, he has had difficulty hearing phone conversations in the left ear and must move the headset to the right.  He has no pain or vertigo but sometimes feels off-balance when walking at night and holds onto walls.  Vital signs are within normal limits.  Physical examination reveals normal tympanic membranes with no middle ear effusion on either side.  A tuning fork placed on the forehead is heard best in the right ear.  Air conduction is greater than bone conduction bilaterally.  There is decreased sensation to touch on the left side of the face.  Bilateral upper and lower extremity strength, deep tendon reflexes, and sensation are normal.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d235_549f_bc81_bd90548be135_MD0003_00 This patient with asymmetric sensorineural hearing loss (air conduction > bone conduction, lateralization to the unaffected ear), imbalance, and facial numbness likely has a vestibular schwannoma (acoustic neuroma), a benign tumor of CN VIII Schwann cells that forms in the internal auditory canal. CN VIII is comprised of both the cochlear nerve and vestibular nerves. Therefore, patients with schwannoma often have unilateral hearing loss due to cochlear nerve compression. Although vertigo would generally be expected with acute vestibular nerve damage, most patients with vestibular schwannoma do not experience vertigo because the tumor's slow growth allows for central compensation of gradual unilateral loss of input; however, imbalance can still manifest when patients are deprived of visual input (eg, walking at night). As the tumor expands from the internal auditory canal into the cerebellopontine angle, it may compress CN V (causing facial numbness) and CN VII (causing facial weakness). cerebellopontine angle Patients require an audiogram and an MRI with contrast of the internal auditory canal. In select patients, observation may be appropriate; otherwise, treatment is with surgical resection or radiation therapy. internal auditory canal (Choice A) A cholesteatoma is an erosive, expansile mass of keratin debris in the middle ear. Although it may present with unilateral hearing loss, the hearing loss is usually conductive (ie, bone conduction > air conduction, lateralization to the affected ear), often with otorrhea and a pearly white mass in the middle ear. (Choice B) Eustachian tube dysfunction may present with asymmetric hearing loss, but it is conductive rather than sensorineural. It also is accompanied by pain, popping sounds, and middle ear effusion. (Choice C) Herpes zoster oticus (reactivation of varicella zoster virus involving CN VIII) can cause hearing loss and imbalance. However, it also presents with severe pain and a vesicular rash. Facial paralysis (CN VII) rather than numbness (CN V) is also characteristic. (Choice D) Although Ménière disease causes asymmetric sensorineural hearing loss, it is characterized by discrete episodes of spinning vertigo, hearing loss, and aural fullness. Subtle imbalance and facial numbness are not typical. (Choice E) Vertebrobasilar insufficiency could cause imbalance. However, isolated hearing loss is rare; other classic symptoms include diplopia, perioral (rather than hemifacial) numbness, dysarthria, and ataxia. Educational objective: Unilateral sensorineural hearing loss with imbalance (CN VIII dysfunction) and decreased facial sensation (CN V dysfunction) are concerning for a vestibular schwannoma, a benign tumor of CN VIII. References: Gait instability in patients with acoustic neuroma. (http://www.ncbi.nlm.nih.gov/pubmed/15224880)

A 52-Year-Old Man Comes to the Office for Evaluation of Hearing