Otosclerosis

Question 1

Pathophysiology of otosclerosis

Answer 1

Remodelling of the small bones in the middle ear, leading to conductive hearing loss

Question 2

Inheritance of otosclerosis

Answer 2

Autosomal dominant

Question 3

Which bone is normally affected in otosclerosis

Answer 3

Base of the stapes where it attaches to the oval window

Causes stiffening and fixation and prevents it from transmitting sound effectively

Question 4

Presentation of otosclerosis

Answer 4

Patient < 40 yo presenting with unilateral or bilateral hearing loss or tinnitus

Affects lower-pitched sounds more

Patient can experience their voice as being loud compared to the environment - therefore talk quietly

Question 5

Examination of otosclerosis

Answer 5

Otoscopy - normal

Weber’s test - normal if bilateral otosclerosis

• If unilateral, sound louder on affected side

Rinne’s test - BC > AC
Sound easily heard when on mastoid process but not when near ear canal

Question 6

Investigations for otosclerosis

Answer 6

Audiometry - conductive hearing loss pattern.

Hearing loss at lower frequencies

Tympanometry -reduced admittance of sound as the tympanic membrane is stiff and non-compliant and does not absorb sound reflecting most of it back

High-resolution CT scans - detect bony changes associated with otosclerosis,
(not required)

Question 7

Management of otosclerosis

Answer 7

Conservative - use of hearing aids

Surgical -stapedectomy or stapedotomy