Chapter 40 - Otosclerosis Flashcards Preview

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Flashcards in Chapter 40 - Otosclerosis Deck (22)
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1
Q

Does otosclerosis involve the cochlea?

A

Rarely

2
Q

Pathogenesis of otosclerosis

A

altered bony metabolism in otic capsule
ongoing resorption and deposition of disorganized bone
Results in fixation of ossicles
Normally, endochondral Ca complete by 1 yo in otic capsule
Bone becomes metabolically active, well-vascularized bone (spongiotic) or densely mineralized (sclerotic)

3
Q

Contributing factors to otosclerosis

A

measles, autoimmunity, multiple endocrine abnormalities, low fluoride consumption

4
Q

Can otosclerosis present with SNHL?

A

Rarely

5
Q

Epidemiology otosclerosis

A

White female 10-40 yo (2:1 F-M)

6
Q

How many patients have bilateral otosclerosis

A

80%

7
Q

How many otosclerosis patients develop SNHL?

A

20-30%

8
Q

Where does otosclerosis begin fixating the ossicles?

A

Anterior stapes footplate

9
Q

Presentation of otosclerosis

A

Most common: adult-onset progressive CHL uni or bilat
Second most common sx: tinnitus
Hearing may improve in noisy environments (Paracusis of Willis)
Rarely have vestibular sx

10
Q

Genetics of otosclerosis

A

AD, incomplete penetrance

11
Q

How many cases of otosclerosis have a FHx?

A

50%

12
Q

Schwartze sign

A

reddish hue seen through TM
Increased vascularity of bone over promontory
May be seen early, not always present

13
Q

Otosclerosis audiogram

A

Worse at low frequencies
Carhart notch where bone conduction dips at 2000 Hz looking like a SNHL
Caused by inertia of ossicular chain

14
Q

Acoustic immitance testing in otosclerosis

A

As tympanometry
Stapedial reflex present early but may be biphasic
As disease progresses, lose stapedial reflex

15
Q

Which image is good at detecting otosclerosis

A

High Res CT

16
Q

Non-surgical treatment of otosclerosis

A

hearing aid

can target osteoclasts with bisphosphonates, sodium fluoride, but neither are consistently recommended

17
Q

Which ear to operate on if bilateral otosclerosis

A

poorer hearing ear first

If successful, the other ear 6 months later

18
Q

Risks of stapes surgery

A

SNHL, vertigo, CN VII, taste, continued CHL, prosthesis extrusion/displacement, TM perf

19
Q

Sx that often require revision stapes surgery

A

CHL, vertigo, SNHL, distorsion of sound

Do CT T bones prior to considering revision

20
Q

How does revision surgery differ from initial stapes surgery in terms of success?

A

Decreased success, increased risk of SNHL

21
Q

Lasers used for stapedotomy

A

CO2 (best at closing ABG)

Argon, KTP, Er-YAG

22
Q

Two anatomical abnormalities making stapes surgery difficult

A

persistent stapedial artery- may ligate if necessary
overriding CN VII- retract gently
Can still do the operation

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