A 30 years woman presents with progressive conductive deafness bilaterally. The most common cause is –
**Core Concept**
Conductive deafness is a type of hearing loss characterized by a problem with the transmission of sound waves through the middle ear. It is often caused by a dysfunction in the middle ear apparatus, including the ossicles (malleus, incus, and stapes), the eardrum (tympanic membrane), or the middle ear muscles.
**Why the Correct Answer is Right**
The most common cause of progressive conductive deafness is otosclerosis, a condition where abnormal bone growth in the middle ear causes fixation of the stapes bone. This fixation prevents the stapes from vibrating in response to sound waves, leading to a conductive hearing loss. Otosclerosis typically affects young women and often presents bilaterally. The pathophysiology involves abnormal bone remodeling in the otic capsule, leading to stapes fixation and subsequent hearing loss.
**Why Each Wrong Option is Incorrect**
**Option A:** Otitis media with effusion is a common cause of conductive hearing loss, but it typically presents acutely and resolves with treatment, rather than being progressive.
**Option B:** Ototoxicity is a common cause of sensorineural hearing loss, not conductive hearing loss.
**Option C:** Perforated eardrum can cause conductive hearing loss, but it is typically sudden in onset and not progressive.
**Clinical Pearl / High-Yield Fact**
Otosclerosis is a classic example of a condition where the pathophysiology is closely linked to the patient's age and sex. It is essential to consider this when evaluating a young woman with progressive conductive hearing loss.
**Correct Answer: B. Ototoxicity is a common cause of sensorineural hearing loss, not conductive hearing loss.