This document discusses otosclerosis, a primary disease of the bony labyrinth that causes stapes fixation and conductive deafness. It begins by listing the learning objectives, which include understanding what otosclerosis is and its causes, types, signs and symptoms, differential diagnosis, diagnostic evaluation, and treatment/management. The document then presents a case study of a 29-year-old female with hearing loss and discusses evaluating her diagnosis, differential diagnoses, management plan, and treatment. It provides details on the etiology, types (stapedial, cochlear, histologic), gross and microscopic appearance, symptoms, signs, and differential diagnosis of otosclerosis.

1. OTOSCLEROSIS
PRESENTED BY
DR AWAIS IRSHAD

2. LEARNING OBJECTIVES
• What is otosclerosis & its causes
• Different types of otosclerosis
• Signs & symptoms
• Differential diagnosis
• Diagnostic evaluation
• Treatment & Management
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CBL 7
THEME: OTOSCLEROSIS
A 29 years old female has presented in ENT opd with history
of difficulty in hearing for approximately 10 months. She also
complains of noise in the ear for the past 6 months. According
to her, the hearing loss is progressing in the past two months
when she had conceived.
1. What specific questions will you ask to reach the
diagnosis?
2. Give differential diagnosis?
3. Give management plan of your diagnosis?
4. What are the different types and which one is most
common?
5. Write the treatment of your diagnosis

4. OTOSCLEROSIS
• Otosclerosis (otospongiosis) is a primary
disease of the bony labyrinth in which
endochondrial layer of the bony capsule is
replaced by foci of spongy bone
• causes stapes fixation and conductive
deafness
• Involvement of other areas causes
sensorineural deafness
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5. ETIOLOGY
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6. TYPES OF OTOSCLEROSIS
1. Stapedial otosclerosis.
Stapedial otosclerosis causing stapes fixation.
Conductive deafness is the most common variety.
Lesion starts just in front of the oval window in an
area called “fissula ante fenestram and is the site of
predilection (anterior focus).
Lesion may start behind the oval window (posterior
focus),
Around the margin of the stapes footplate
(circumferential),
In the footplate but annular ligament being free
(biscuit type).
Sometimes, it may completely obliterate the oval
window niche (obliterative type)
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2. Cochlear otosclerosis.
Cochlear otosclerosis involves region of
round window or other areas in the otic
capsule, and may cause sensorineural
hearing loss probably due to liberation of
toxic materials into the inner ear fluid.
3. Histologic otosclerosis.
This type of otosclerosis remains
asymptomatic and causes neither
conductive nor sensorineural hearing loss

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Grossly
Otosclerotic lesion appears chalky white, greyish or yellow
and sometimes, it is red in colour due to increased
vascularity
Microscopically
spongy bone appears in the normally dense enchondral
layer of otic capsule.
. Immature active lesion
numerous marrow and vascular spaces with plenty of
osteoblasts and osteoclasts and a lot of cement substance
which stains blue
. Mature foci
less vascularity, more bone and more of fibrillar substance
than cementum, and is stained red

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SYMPTOMS

10. • (Schwartze sign).
• Normal eustachian tube function
• Tuning fork tests show negative Rinne and
webers lateralized to the ear with greater
conductive loss
• PTA shows loss of air conduction more for lower
frequency
• Bone conduction is normal
• In some cases, there is a dip in bone
conduction curve at 2000 Hz and is called
Carhart’s notch.
• Tympanometry may be normal in early cases
but later shows a curve of ossicular stiffness.
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SIGNS

11. Differntial diagnosis
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