Background
- A disorder limited to the temporal bone, causing breakdown and poor reformation of the ossicles (mainly stapes footplate) causing profound conductive and sensorineural hearing loss.
- There is usually a family history (50%- autosomal dominant- variable penetrance) and is often associated with osteogenesis imperfecta (a triad of hearing loss, spontaneous bone fractures and blue sclera).
- Common cause of hearing loss in young adults; slightly more common in females
Presentation
- Hearing loss- progressive and conductive; often bilateral
- Hearing is often better in loud environments (e.g. crowded rooms) (paracusis)
- Loss of deep-pitch is lost first
- Hearing is often better in loud environments (e.g. crowded rooms) (paracusis)
- 75% will also have tinnitus (progresses with hearing loss) and some will have mild transient vertigo
- Dizziness is uncommon but occasionally vestibular involvement can cause severe nystagmus and vertigo (rotational)
- More common to present in pregnancy, with menstruation (exacerbates) or at menopause
- Otoscopy is usually normal but around 10% show a reddish-blue discolouration over the promontory (Schwarte’s sign)
Investigations
- Audiometry – (usually conductive but occasionally mixed hearing loss)
- Tympanometry- stiffness curve (low tympanic compliance)
- Fine-slice CT- ‘halo’ sign in the temporal bone (abnormal deposition)
Management
- Hearing aids
- Occasionally sodium fluoride or bisphosphonates can be used but surgery (stapedectomy/stapedotomy) is the mainstay of ‘definitive’ treatment
Prognosis/Complications
- Severe hearing loss (rarely complete deafness)
- Stapedectomy
- Risk of total hearing loss, facial nerve injury, eardrum perforation (correctable), taste disruption (transient in most cases); worsening tinnitus
- In general, however, results are good