Hearing disorders of the middle ear

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Hearing disorders of the middle ear

• Tympanic membrane
• Perforations
• Tympanosclerosis Thickening/Scarring

http//www.ent-usa.com/eardrum_and_middle_ear.htm
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http//www.bestforhearing.com/images/normal-ed.jpg
http//www.hmc.psu.edu/ume/fcmonline/case32/images
/normal-ear.jpg
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TM Perforation
http//www.ghorayeb.com/files/TYMPANIC_PERFORATION
_LEFT_LABELED.jpg
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TM Perforation
http//texasearcenter.com/userfiles/Image/tmp-1.jp
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• Consequences
• Mild hearing loss
• Treatment
• In some cases, spontaneous recovery (depends on
  location)
• Myringoplasty Surgical reconstruction

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Middle ear cavity

• Otitis media Very common (70 of children in
  the U.S.)
• Infection of the mucous membrane lining the
  middle ear
• Predisposing factors
• Poorly functioning Eustachian tubes
• Barotrauma
• Abnormal functioning of mucous membrane cilia
• Anatomical deformities
• Gender and demographic factors
• Exposure to toxic fumes

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TM Retraction
http//img.medscape.com/pi/emed/ckb/otolaryngology
/834279-858557-860080-860208.jpg
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Acute OM
http//www.mdconsult.com/das/book/body/161330440-2
/0/1608/f4-u1.0-B978-1-4160-2450-7..50641-1..gr3.j
pg
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Acute OM
http//upload.wikimedia.org/wikipedia/commons/5/58
/Otitis_media_entdifferenziert2.jpg
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Acute OM
http//knol.google.com/k/-/-/Y0fzk46N/nxV32A/AOM.j
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Possible mechanisms

• Through ruptured tympanic membrane
• Through Eustachian tube
• Through blood

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Characteristics of otitis media infection

• Two types Acute and chronic
• Rapidly progressive
• Negative pressure in middle ear because of ET
  malfunction
• TM is retracted and appears red
• Pain, high temperature, pus accumulates in middle
  ear mucosa
• In severe cases, TM ruptures due to pressure.
• If left untreated, can progress to mastoid air
  cells and cause mastoiditis.

http//www.ent-usa.com/eardrum_and_middle_ear.htm
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Consequences

• Flat conductive hearing loss (degree depends on
  the amount of fluid)
• Low static compliance
• Type B tympanogram
• Absent reflexes
• Absent OAEs
• High latencies for all ABR peaks

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Treatment

• Antibiotics
• Surgery
• Myringotomy and suction
• Mastoidectomy (if infection has spread to mastoid
  region)
• Tympanoplasty

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PE Tubes
http//www.pedisurg.com/PtEducENT/tube_in_TM.jpg
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Complications of otitis media

• Cholesteotoma Sac-like growth due to presence of
  skin in the middle ear.
• Dangerous, progressive, highly erosive
• Foul-smelling discharge (otorrhea)
• Treatment Surgical removal
• http//www.ent-usa.com/eardrum_and_middle_ear.htm
  

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Cholesteatoma
http//chicagoear.com/med_info/images_med_info/cho
lesteatoma.jpg
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Cholesteatoma
http//www.earsurgery.org/images/Photo-3120copy.j
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Cholesteatoma
http//my.clevelandclinic.org/PublishingImages/Hea
d_Neck/cholesteatoma.jpg
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Facial palsy

• If erosion of bone occurs, facial nerve may be
  exposed.
• Partial/Full paralysis of one side of the face.
• Treatment Surgery

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Eustachian tube problems

• Cause Infections, allergies, blockage due to
  overgrown adenoids, structural problems.
• Consequences Negative middle ear pressure,
  retracted TM.
• Audiometric findings Mild conductive hearing
  loss, normal static compliance, type C
  tympanogram.

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Methods to open ET

• Valsalva Close nostrils and cheek and blow out.
• Toynbee Close nostrils and swallow
• Complications of ET malfunction
• Serous effusion
• Mucous otitis media

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Otosclerosis

• Causes Hereditary in 70 of cases.
• Progressive in nature
• Higher incidence in women, adults.
• Clinical manifestation Spongy bone formation
  over the stapes footplate. Footplate becomes
  fixed in the oval window.

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Other clinical signs

• Progressive hearing loss
• Tinnitus
• Difficulty hearing while chewing
• Very vascular promontory, rosy glow through TM
  (Schwartze sign)
• Paracusis willisii Speech easier to understand
  in the presence of background noise.

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Audiometric findings

• Low frequency conductive hearing loss with
  air-bone gap.
• As disease progresses, hearing loss spreads to
  high frequencies.
• Bone conduction is affected, primarily at 2000 Hz
  (called Carharts notch).
• Type As tympanogram, absent reflexes

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Treatment

• Earlier Surgery to free immobilized stapes
  footplate. Not very successful.
• Fenestration (new window created in lateral
  semicircular canal).
• Effects of fenestration 25 dB hearing loss
  to total hearing loss, vertigo, tinnitus, poor
  word recognition scores, facial paralysis,
  repeated infections of cavity
• Stapes mobilization Middle ear cavity exposed
  through incision in TM.
• Effects Immediate improvement in hearing,
  however, refixation of stapes often occurred.
• Most successful treatment Stapedectomy. Replaced
  with prosthesis
• Modification Stapedotomy

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Inner ear

• Series of interconnecting canals or labyrinths
  in the temporal bone
• Two types
• Osseous
• Bony
• Bigger cross-sectional area
• Contains fluid called perilymph
• Membraneous
• Soft tissue
• Situated within the bony labyrinth
• Contains fluid called endolymph

http//research.meei.harvard.edu/Otopathology/3dmo
dels/download.html