Otosclerosis Flashcards
What happens in otosclerosis?
Normal bone is replaced by vascular spongy bone. The stapes footplate becomes thickened and eventually fuses with the oval window causing a progressive conductive deafness.
What is the inheritance pattern?
Autosomal dominant
What age does it typically affect?
Young adults 20-40
What percentage have a family history?
50%
What percentage are affected bilaterally?
85%
What can accelerate the symptoms?
Pregnancy - may be due to higher levels of oestrogen
Otosclerosis may be precipitated by pregnancy in those who are genetically predisposed
What symptoms occur?
Conductive deafness
Hearing often better with background noise
Tinnitus
Mild, transient vertigo
In 10% of people with otosclerosis, what can happen to the tympanic membrane?
Schwartze’s sign = a pink tinge to the TM caused by hyperaemia
How can it be managed?
Hearing aid
Surgery: stapedectomy - replaces stapes with artificial bone made of plastic or metal
Does it tend to affect low frequencies or high?
Equal as disease progresses. Initially lower pitched sounds affected more
Do those with otosclerosis typically speak quieter than those with nerve deafness or louder?
Quieter
Why does it cause hearing loss?
The ossicles (especially stapes) can not pass sound waves into ear ear as efficiently
What virus has been linked to otosclerosis?
Measles
Is it more common in women or men?
Women
What is seen on audiometry?
A dip at 2Hz on masked bone conduction = Cahart’s notch
