Introduction

Otosclerosis describes the replacement of normal bone by vascular spongy bone. It causes a progressive conductive deafness due to fixation of the stapes at the oval window. Otosclerosis is autosomal dominant and typically affects young adults.

Epidemiology

  • Incidence: 30.00 cases per 100,000 person-years
  • Peak incidence: 30-40 years
  • Sex ratio: more common in females 2:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Onset is usually at 20-40 years - features include:
  • conductive deafness
  • tinnitus
  • normal tympanic membrane in most patients
    • 10% of patients may have a 'flamingo tinge', caused by hyperaemia
  • positive family history