• Clinical science

Otosclerosis

Abstract

Otosclerosis refers to abnormal bone growth of the bony labyrinth, which contains the structures of the inner ear. It manifests primarily at the stapes, which becomes increasingly fixated to the oval window. This process leads to progressive conductive hearing loss because the ossicle's ability to vibrate becomes increasingly limited. Frequently, the other ear is also affected. Left untreated, the disease can progress to deafness. Audiometry reveals decreased air conduction and a characteristic Carhart's notch in the bone conduction curve. Replacement of the upper part of the stapes with a prosthesis (stapedotomy) is the treatment of choice.

Epidemiology

  • Sex: > (2:1)
  • Age of onset: 20–40 years
  • Ethnicity: primarily affects whites

References:[1][2]

Epidemiological data refers to the US, unless otherwise specified.

Etiology

References:[1]

Pathophysiology

References:[3]

Clinical features

Symptoms may increase during pregnancy or following menopause because of hormonal changes!

References:[1][2]

Diagnostics

  • Pure tone audiometry
    • ↓ Air conduction (especially for lower frequencies)
    • Carhart's notch: an increase in the bone conduction threshold at 2,000 Hz (which is seen as a dip in the bone conduction curve)
  • Impedance audiometry: absent stapedius reflex

References:[1][2][4]

Treatment

  • The progression of otosclerosis cannot be significantly influenced by conservative therapy.
  • Surgical procedures
    • The stapes is partly (stapedotomy; ) or completely (stapedectomy) replaced by a prosthesis.[2]
    • Cochlear implant: in the case of bilateral deafness
last updated 12/01/2017
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