11. Otosclerosis, tympanosclerosis

  • Otosclerosis
    • Abnormal bone growth of the bony labyrinth
    • The stapes becomes increasingly fixated to the oval window -> progressive conductive HL
    • Can also affect cochlea
    • Epidemiology
      • Whites
      • Females
      • Adults
    • 50% autosomal dominant, 50% sporadically
    • Diagnosis
      • Decreased air conduction on pure tone
      • Carhart notch on audiogram
      • Normal otoscopy
    • Treatment
      • Stapes replaced by prosthesis – stapedotomy


  • Tympanosclerosis
    • Scarring of tympanic membrane and cavity due to recurrent otitis externa or media
    • Asymptomatic or conductive hearing loss due to fixation of ossicles
    • White calcified plaques on otoscopy
    • Myringosclerosis – only tympanic membrane
      • Rarely symptoms
    • Treatment
      • Surgical removal of sclerosis
        • Usually recurs