A 52-year-old man with a 10-year history of progressive bilateral hearing loss undergoes audiometry showing air-bone gaps of 35 dB bilaterally, normal speech discrimination, and normal middle ear pressure on tympanometry. All of the following are consistent with his diagnosis EXCEPT:

Explanation

## Clinical Case: Bilateral Conductive Hearing Loss with Normal Middle Ear Pressure ### Case Analysis **Key Clinical Features:** - Progressive bilateral hearing loss over 10 years - Air-bone gap of 35 dB bilaterally (diagnostic of conductive loss) - Normal speech discrimination (rules out sensorineural component) - Normal middle ear pressure on tympanometry (rules out otitis media) - Age 52 (adult-onset) **Diagnosis: Otosclerosis** — the most common cause of progressive conductive hearing loss in adults. ### Otosclerosis: Pathophysiology and Clinical Features **High-Yield:** Otosclerosis is abnormal bone remodeling at the oval window, causing stapes fixation. It typically presents in the 3rd–5th decade with progressive conductive or mixed hearing loss. | Feature | Finding | |---------|----------| | Pathology | Stapes footplate fixation at oval window | | Audiometry | Air-bone gap (conductive or mixed pattern) | | Speech discrimination | Normal (cochlea intact initially) | | Tympanometry | Normal (middle ear pressure normal) | | Bilateral involvement | 70% of cases | | Progression | Slow, over years to decades | ### Evaluation of Each Option **Option 0 — Correct:** Otosclerosis is the most common cause of progressive conductive hearing loss in adults, particularly in this age group and with bilateral presentation. **Option 1 — Correct:** Stapes fixation (stapes footplate ankylosed to oval window) is the pathological hallmark of otosclerosis and the expected finding at surgery (stapedectomy/stapedotomy). **Option 3 — Correct:** By definition, conductive loss shows air conduction thresholds elevated (worse) compared to bone conduction thresholds, creating the air-bone gap. **Option 2 — INCORRECT:** While sodium fluoride was historically proposed for otosclerosis, **there is no strong evidence that it halts disease progression**. Multiple randomized controlled trials have failed to demonstrate significant benefit. Fluoride is not standard therapy and is not recommended in current guidelines. **Clinical Pearl:** The only definitive treatment for otosclerosis is surgery (stapedectomy or stapedotomy), which has >90% success rate in improving hearing. Medical management is supportive; hearing aids are often used. **Warning:** Do not confuse otosclerosis with otospongiosis (the histological term). Otosclerosis is the clinical diagnosis; the underlying bone disease is otospongiosis. **Mnemonic for Otosclerosis — STAPES:** - **S**tapes fixation - **T**hird to fifth decade - **A**dult onset - **P**rogressive - **E**xtra-osseous bone remodeling - **S**urgery is definitive treatment