2.
Definition
A primary disease of the bony otic capsule
characterized by abnormal removal of mature bone
by osteoclasts and replacement with woven bone of
greater thickness, cellularity and vascularity.
Clinical Otosclerosis refers to a lesion that involves
the stapes bone or stapidovestibular joint.
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3.
Most common site is fissula ante fenestram (anterior
to the stapes foot plate) and also seen in the fossula
post fenestram (area in front and behind oval
window)
The bone of otic capsule is unique that it exhibits
very low remodeling and contains small regions of
immature cartilaginous tissue called GLOBULI
INTEROSSEI.
Blue Mantles, an earliest histological alterations of
otic capsule that stain more basophilic.
6.
Epidemiology
Gender
Histologic otosclerosis – 1:1 ratio
Clinical otosclerosis – 2:1 (W:M)
• Increase progression during pregnancy (10%-17%)
• Bilaterality more common (89% vs. 65%)
7.
Epidemiology
Age
• 15-45 most common age range of presentation
• Youngest presentation7 years
• Oldest presentation 50s
• 0.6% of individuals <5 years old have foci of
otosclerosis
8.
Etiology
The exact cause is unknown but many factors have
been proposed such as:
• Genetic
• Autoimmune
• Infections
• Endocrine (pregnancy)
• Trauma
• Vascular
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9.
• Hereditary(Autosomal Dominant)
• More common in whites than blacks
• Uncommon in Asian
• Sporadic cases were reported.
• Defects in COL1A1 Gene
• defects in expression of the COLlAl gene has revealed a
significant association between both familial and
sporadic cases
Genetic
10.
Type 1 osteogenesis imperfecta shares both clinical
and histologic similarities with otosclerosis.
Half of all patients with type 1 osteogenesis
imperfecta develop hearing loss that is clinically
indistinguishable from clinical otosclerosis.
Patients with clinical otosclerosis have blue sclera, a
feature that is found in all patients with type 1
osteogenesis imperfecta.
Osteogenesis Imperfecta
11.
Infectious (Measles)
Measles RNA was found in footplate specimens
Elevated levels of anti measles antibody found in
perilymph from patent undergoing stapedectomy.
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12.
a form of autoimmune disease with humoral
autoimmunity to Type II collagen.
Elevated circulating antibodies to type II collagen are
found in patients of otosclerosis
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Autoimmune
14. Affects the Otic and labyrinth
Capsule
Enlargement of the Perivascular
Space
Bone Absorption by osteoclast
activity
New Bone deposition by osteocytes
Containing vascular space in center
Lamellar Bone
With time mucoperiostium of
middle ear increases in thickness
and becomes vascular
Reddish Hue through the TM and
disease advances
Involvement of Bony
labyrinth
Involvement of
foot plate.
Cochlear
Otosclerosis
Stapedial
Otosclerosis
15.
Histologically
Lesion can be divided into
Active-Spongy structure immature osseous tissue
with numerous dilated vascular channels with
osteoclastic giant cells
Inactive/Mature
• End stage of bone transformation ,characterized by
solid compact lamellar tissue.
Siebenmann – first to describe the microscopic appearance
16. 16
The foci demonstrates two phases:
Early spongiotic phase (otospongiosis)
Osteocytes, histiocytes, osteoclasts
Active reabsorption of bone
Stains blue (blue mantles) on using H&E stain
Dilated vessels (Schwartze’s sign)
Late or Sclerotic phase
Formation of new bone in resorption areas
New bone is dense and sclerotic
Stains red on using H&E stain
Starts in endochondral bone then involves endosteal &
periosteal layers and membranous labyrinth as disease
progress
17.
Anterior Focus
Most common, at fissula ante fenestram
Posterior Focus
Lesion spreading from posterior oval window to annular
ligament
Circumferential
Lesion flows across the ligament totally obliterating the
annular ligament
Biscuit type
Lesion replacing entire footplate, but no involvement of
annular ligament leading to a solid footplate
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Types of Stapedial fixation
18.
Obliterative
Completely obliterates the oval window
Other areas are:
Round window, the apex of the cochlea, the cochlear
aqueduct, the semicircular canals, and the stapes
footplate itself
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Types of Stapedial fixation
20.
Gradual onset of hearing loss progressing slowly
In 70% cases hearing loss is bilateral
Usually becomes apparent around the age of 30
Loss noticeable when it reaches 25 to 30 dB
Unilateral loss noticed even later, problem with
localization of sound
Positive family history
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History
21.
SYMPTOMS
Low modulated voice (BC is more ,patients hears their
own voice.
Deafness-Mainly Conductive hearing loss,
Paracussis Willisi-Patient will hear better in noisy
surroundings.
Tinnitus
Vertigo
Clinical Features
22.
Hearing Loss
Conducting Hearing Loss (CHL)
• Stapedial fixation
• Hearing impairment ranging from 5dB to 60dB.
• Caused primarily by narrowing and impairment of the
annular ligament, at the posterior stapediovestibular joint
space.
Sensorineural Hearing Loss (SNHL)
• Cochlear otosclerosis
• the sensory and neural elements of the cochlea, such as
hair cells, spiral ganglion cells and stria vascularis, are
intact or their impairment is insufficient to account for the
observed sensorineural hearing impairment.
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23.
OTOSCOPY
• SCHWARTZE SIGN:- red blush color occasionally
seen over promontory or anterior to oval window
• Pneumo-otoscopy used to rule out other causes of
CHL such as middle ear serous fluid or small
perforation
TUNING FORK TEST
• Hearing loss progresses form low frequencies to high frequencies
• Rinne Test-Negative
• Weber Test-Laterlized to worst ear.
• ABC-Normal
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Physical Examination
24.
Pure Tone Audiometry
CARHART’S NOTCH
Proposed theory
Stapes fixation disrupts the normal ossicular resonance (2000
Hz)
Normal compressional mode of bone conduction is disturbed
because of relative perilymph immobility
Mechanical artifact
Reverses with stapes mobilization
Speech Audiometry
Normal except in those with cochlear involvement.
27.
High resolution CT scan
Shows subtle areas of demineralization
In case of cochlear involvement it shows “double ring
sign”
MRI
Done for patients with unusual presentation
Detects congenital anomalies of cochlea
Excludes retrocochlear pathology eg. Acoustic
neuroma
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Radiological Investigations
30.
Treatment Options
Hearing aid
Medical management
Surgical management-The ‘Gold’ reference standard
of Diagnosis is Surgery
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31.
Hearing Aid
Very effective in early stage of disease
But can be used in advance stage, if:
Surgery is contraindicated
Patient refuses the surgery
In far-advance cases it is required, even after
stapedotomy
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32.
Medical Management
Aim is to Stabilize the disease by
reduction of the osteoclastic bone resorption
increase osteoblastic bone formation
Inhibits proteolytic enzymes that are cytotoxic to
cochlea.
Slows the progression of sensorineural hearing loss
Not commonly used
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33.
Tab. Sodium fluoride
Dose : 50 – 75 mg/day OD
Duration : 3 months – 2 years
Function
helps to hasten the maturity of active focus and arrest
further progression of cochlear loss
It has antienzymatic action on proteolytic enzymes
which are cytotoxic to cochlea.
Indications:
Cochlear otosclerosis
Active stapedial otosclerosis
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Sodium Fluoride Therapy
34.
Side effects :
Fracture of long bones and spine due to fluorosis.
Nephritis.
Gastritis
Contraindications:
Pregnancy & lactation
Patient with kidney stones / nephritis
Patient with RA
Sodium Fluoride Therapy
35.
Surgical Management
Poorer ear always chosen for surgery
Done preferably under local anesthesia so patient can
notify surgeon if vertigo occurs during procedure
Options are:
Stapedotomy
Stapedectomy
Lasers -Lesser complications
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Hinweis der Redaktion
Otic capsule
The embryonic cartilage capsule that surrounds the inner ear mechanism and develops into bony tissue.
In very advance cases whole foot plate +oval window round and cochlear bony labrynth –Malignant otosclerosis.
Schwartze’s sign not usually visible at otoscopy. TM will be normal in most cases 90%+
Tinnitus indicates SNHL
Patients are soft speakers as they hear themselves thru bone conduction
Resistance given by TM.
Only for complex presentations when we need to exclude differentials.
Pagets---excessive bone resorption followed by an increase in bone formation. This osteoclastic overactivity followed by compensatory osteoblastic activity leads to a structurally disorganized mosaic of bone (woven bone), which is mechanically weaker, larger, less compact, more vascular, and more susceptible to fracture than normal adult lamellar bone.
Obervation: is an option. Only during early stage of disease when the CHL is minimum