A 34-year-old woman comes to the office due to difficulty hearing, especially in the left ear. The hearing loss has worsened over the past year, and she is now having trouble hearing people at work; however, when the environment is noisy, she can understand speech better than when she is in a quiet room. The patient also hears ringing in the left ear. She has no dizziness, vertigo, or ear pain. She has had no significant noise exposure. The patient has no other medical conditions and takes no medications. Her mother had surgery for hearing loss when she was in her 40s. On examination, the tympanic membranes are clear with a good light reflex, good landmarks, and no middle ear effusion. There is a slight reddish hue behind the left tympanic membrane. Which of the following is the most likely mechanism of this patient's condition?

Question

A 34-year-old woman comes to the office due to difficulty hearing, especially in the left ear.  The hearing loss has worsened over the past year, and she is now having trouble hearing people at work; however, when the environment is noisy, she can understand speech better than when she is in a quiet room.  The patient also hears ringing in the left ear.  She has no dizziness, vertigo, or ear pain.  She has had no significant noise exposure.  The patient has no other medical conditions and takes no medications.  Her mother had surgery for hearing loss when she was in her 40s.  On examination, the tympanic membranes are clear with a good light reflex, good landmarks, and no middle ear effusion.  There is a slight reddish hue behind the left tympanic membrane.  Which of the following is the most likely mechanism of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d8c3_f36f_bc81_4d368c833729_MD0003_00 This patient has hearing loss that paradoxically improves (with regard to speech discrimination) in noisy environments, consistent with conductive hearing loss (CHL). Given her young age and family history of hearing loss at a young age, this presentation suggests otosclerosis. Otosclerosis is inherited in an autosomal dominant pattern with incomplete penetrance. It results from an imbalance of bone resorption and deposition, causing stiffening and fixation of the ossicular chain (malleus, incus, stapes), primarily the stapes. Because the ossicles function as a lever connecting the tympanic membrane to the oval window to amplify sound energy, this stiffening results in CHL. As with other causes of CHL, patients with otosclerosis can have paradoxical improvement of speech understanding in a noisy environment (a phenomenon called the paracusis of Willis), possibly because CHL dampens the competing background noise, thereby allowing speech to be heard more clearly. ossicular chain Ear examination is generally unremarkable, although excessive bony resorption can expose underlying blood vessels, leading to a reddish hue sometimes seen behind the tympanic membrane. Management involves hearing amplification or surgical reconstruction of the stapes. (Choice B) Degeneration of neuronal cell bodies (which can occur in presbycusis) is seen in older individuals and presents with bilateral, symmetric sensorineural hearing loss (SNHL). Unlike CHL, SNHL is characterized by worse speech understanding with increasing background noise. (Choice C) Increased fluid in the cochlea (which is thought to occur in Ménière disease) can cause a unilateral hearing loss in young adults that sometimes runs in families. However, it presents with episodic vertigo, hearing loss, and aural fullness. (Choice D) A lamellated basement membrane is characteristic of Alport syndrome, which can cause hereditary SNHL (not CHL) due to damage of the basement membrane in the cochlea. It typically presents with recurrent hematuria in childhood. (Choice E) A neoplastic growth involving CN VIII (vestibular schwannoma) would also cause a unilateral hearing loss and is sometimes hereditary (eg, neurofibromatosis, type 2). However, it would present with SNHL and a normal otoscopic examination (no reddish hue). Educational objective: A conductive hearing loss (CHL) may show improved speech understanding in background noise. CHL in a young woman with a positive family history of hearing loss likely represents otosclerosis, which is characterized by bony overgrowth of the stapes that causes stiffening of the ossicular chain. References: Schwartze sign. (http://www.ncbi.nlm.nih.gov/pubmed/30422516) Controversies in the evaluation and management of otosclerosis. (http://www.ncbi.nlm.nih.gov/pubmed/29502731)

A 34-Year-Old Woman Comes to the Office Due to Difficulty