EN4.13 | Otosclerosis — Summary & Reflection

KEY TAKEAWAYS

Otosclerosis is a disease of abnormal otic capsule bone remodelling causing stapes footplate fixation and progressive conductive hearing loss. Key points:

• Presentation: young adult (typically female), bilateral progressive CHL, normal-appearing TMs, paracusis Willisii, positive family history, worsening with pregnancy.
• Pathophysiology: fenestral (stapes fixation, CHL) or cochlear (mixed/SNHL); Schwartze sign = active vascular disease; Carhart's notch = mechanical BC dip at 2000 Hz — NOT cochlear loss.
• Investigations: PTA (air-bone gap, Carhart's notch), type As tympanogram (reduced compliance), absent stapedial reflex, HRCT (halo sign for cochlear disease).
• Tuning forks: Rinne negative (BC>AC); Weber to the MORE affected (worse) ear — opposite to SNHL.
• Management: sodium fluoride (arrests active disease; does not restore hearing); stapedotomy (gold standard — small fenestra piston, >90% air-bone gap closure); hearing aid (if surgery declined/unfit).
• Surgical note: Carhart's notch disappears after successful stapedotomy, confirming its mechanical origin.

REFLECT

Recall the woman in the opening scenario who heard better in noise — a puzzling symptom that makes more sense now that you understand the mechanics of conductive hearing loss and paracusis Willisii. Reflect on how you would explain to this patient what otosclerosis is, why she hears better in noise, why her mother also has it, and what surgery involves — in language a non-medical person can understand. Consider also what you would say to her about surgery during a future pregnancy, and how you would weigh the risks of a 1–2% chance of total deafness in that ear against the benefit of restored hearing.