Week 6: Middle Ear Disorders/Diseases (II) Flashcards
What is Otosclerosis?
a disease of the bony labyrinth—bone tissue of the bony labyrinth begins to grow abnormally
Where is the word Otosclerosis derived from, and what does it mean?
derived from Greek, it means abnormal hardening (sclerosis) of the ear (oto)
Describe what happens in the bone in Otosclerosis
the “new” bone that grows is soft (otospongiosis) but with time, the soft areas scar and harden (otosclerosis)
What happens when the “new” bone grows over the footplate of the stapes?
the stapes becomes partially or completely fixed
When the “new” bone grows over the footplate of the stapes and caused the stapes to become partially/completely fixed, what does it limit and what type of hearing loss does it result in?
this limits the movement (vibration) of the ossicular chain (decreasing the transmission of sound to the inner ear) resulting in a Conductive hearing loss
When the “new” bone grows over the stapes and inside the cochlea, what type of hearing loss does it result in?
Mixed hearing loss
When the “new” bone only grows inside the cochlea, what type of hearing loss does it result in? How often does this happen?
Sensorineural hearing loss
less frequently
True or False. Otosclerosis tends to run in families (~50% of cases)
true
Otosclerosis tends to run in families (~50% of cases)
Otosclerosis is inherited in an autosomal dominant pattern with variable penetrance, what does it mean?
this means that there is a 50% chance of getting the gene for otosclerosis if one parent has it (dominant), but not everyone with the gene develops symptoms (variable penetrance)
But why do some people with no family history of otosclerosis develop it?
perhaps, in some cases, an autosomal dominant disorder results from a new (de novo) mutation of the gene
What is the female to male ratio of Otosclerosis?
2:1
Otosclerosis is bilateral in up to what percentage of cases?
75%
Otosclerosis occurs most frequently between what ages?
20 and 50 years of age
Initial awareness of hearing loss or an accelerated progression of an existing hearing loss is a common observation when?
during or following pregancy
True or False. Hormonal changes during pregnancy do not stimulate the new bone formation in otosclerosis disease.
false
hormonal changes during pregnancy may stimulate the new bone formation in otosclerosis disease
Several studies have shown that otosclerosis is most common in?
Caucasians, about half as common in the Oriental population, and very rare among Blacks and American Indians
True or False. Otosclerosis will progress to different degrees and at different rates for different people
true
otosclerosis will progress to different degrees and at different rates for different people (not everyone will develop moderate to severe hearing loss)