Otosclerosis

A progressive disease with a marked familial tendency that affects the bony otic capsule

Slowly progressive hearing loss that is usually bilateral and asymmetric, although unilateral disease may occur in up to 30% of patients

Normal tympanic membrane on otoscopic examination

Lesions involving the footplate of the stapes result in increased impedance to the passage of sound through the ossicular chain, producing conductive hearing loss

When otosclerotic lesions involve the cochlea ('cochlear otosclerosis'), permanent sensory hearing loss occurs

Otoscopic examination is to exclude other causes of chronic hearing loss such as cholesteatoma and middle ear effusion

Audiogram to document conductive hearing loss

Weber test should lateralize to the ear with the greater conductive deficit

The conductive hearing loss may be treated either through the use of a hearing aid or surgical replacement of the stapes with a prosthesis (stapedectomy)