9/30/2013

9/30/2013

Answers:

The most common cause of CHL in adults is ---, but the most common cause in children is---.
A) Cerumen Impaction; Otitis Media 
B) TM Perforation; Otitis Media 
C) Otitis Media; Cerumen Impaction 
D) Otitis Media; TM Perforation 
E)Cerumen Impaction; TM Perforation

In adults cerumen impaction is the most common cause, TM perf is the second most common cause.  In children Otitis media is the most common cause.

What is the greatest possible hearing loss, in terms of dB, a CHL can cause?

60 dB.  Hearing loss greater than 60 dB should be considered to have at least some SNL component.  Be suspicious of ossicular discontinuity for loss >50dB.

MC Questions:
What is cochlear otosclerosis?
A) When otosclerosis causes CHL 
B) When otosclerosis causes SNHL 
C) Stiffening of cochlear basal membrane
D) Stiffening of the stapes footplate 
E) None of the above

Free Response Question:
What amount of hearing loss is expected when the canal is impacted with cerumen?

Quick Facts:
Otosclerosis
-abnormalities of bone metabolism affecting labyrinthine bone of inner ear.
-leads to stiffening/fixation of stapes to oval window.
-decreased movement = CHL
-treat with Stapedectomy, 90-95% success rate.
-can cause SNHL aka cohclear otosclerosis