otosclerosis

Otosclerosis is a condition characterized by abnormal remodeling of the temporal bone around the otic capsule, most often affecting the stapes footplate. This leads to a progressive conductive hearing loss, typically presenting in young to middle adulthood. There is a familial component with autosomal dominant inheritance and variable expression; environmental factors, including pregnancy, may influence disease activity. The disease begins with bone remodeling around the oval window (fenestral otosclerosis) and can extend into the cochlear portion (retrofenestral or cochlear otosclerosis), potentially causing sensorineural hearing loss.

Symptoms commonly include gradual hearing loss, especially for low-frequency sounds, a sensation of fullness in the ear, and tinnitus. A noticeable, though not universal, sign is a reddish-bluish blush on the promontory known as Schwartze sign.

Diagnosis relies on audiometry showing conductive hearing loss with a normal tympanic membrane. In the Weber test, hearing usually localizes to the affected ear, while the Rinne test is negative on the affected side (bone conduction greater than air conduction). Tympanometry is typically normal. High-resolution CT of the temporal bone can reveal stapes footplate fixation and lucency around the fissula antefenestram.

Treatment focuses on hearing rehabilitation. Hearing aids are first-line for many patients. If conductive loss persists, surgical management with stapedectomy or stapedotomy and placement of a prosthesis yields substantial improvement in most cases. Cochlear involvement may necessitate a cochlear implant in selected patients. Otosclerosis may progress in some individuals, requiring ongoing follow-up.