Hearing disorders of the middle earHearing disorders of the middle ear

Tympanic membrane: Tympanic membrane:

1.1. Perforations Perforations

2.2. Tympanosclerosis: Thickening/ScarringTympanosclerosis: Thickening/Scarring

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

http://www.bestforhearing.com/images/normal-ed.jpg

http://www.hmc.psu.edu/ume/fcmonline/case32/images/normal-ear.jpg

TM PerforationTM Perforation

http://www.ghorayeb.com/files/TYMPANIC_PERFORATION_LEFT_LABELED.jpg

TM PerforationTM Perforation

http://texasearcenter.com/userfiles/Image/tmp-1.jpg

ConsequencesConsequences

Mild hearing lossMild hearing loss

TreatmentTreatment

In some cases, spontaneous recovery (depends In some cases, spontaneous recovery (depends on location)on location)

Myringoplasty: Surgical reconstructionMyringoplasty: Surgical reconstruction

Middle ear cavityMiddle ear cavity Otitis media: Very common (~70% of children in the U.S.)Otitis media: Very common (~70% of children in the U.S.)

Infection of the mucous membrane lining the middle earInfection of the mucous membrane lining the middle ear

Predisposing factors:Predisposing factors:

Poorly functioning Eustachian tubesPoorly functioning Eustachian tubesBarotraumaBarotraumaAbnormal functioning of mucous membrane ciliaAbnormal functioning of mucous membrane ciliaAnatomical deformitiesAnatomical deformitiesGender and demographic factorsGender and demographic factorsExposure to toxic fumesExposure to toxic fumes

TM RetractionTM Retraction

http://img.medscape.com/pi/emed/ckb/otolaryngology/834279-858557-860080-860208.jpg

Acute OMAcute OM

http://www.mdconsult.com/das/book/body/161330440-2/0/1608/f4-u1.0-B978-1-4160-2450-7..50641-1..gr3.jpg

Acute OMAcute OM

http://upload.wikimedia.org/wikipedia/commons/5/58/Otitis_media_entdifferenziert2.jpg

Acute OMAcute OM

http://knol.google.com/k/-/-/Y0fzk46N/nxV32A/AOM.jpg

Possible mechanismsPossible mechanisms

Through ruptured tympanic membraneThrough ruptured tympanic membrane

Through Eustachian tube Through Eustachian tube

Through bloodThrough blood

Characteristics of otitis media infectionCharacteristics of otitis media infection Two types: Acute and chronicTwo types: Acute and chronic

Rapidly progressiveRapidly progressive

Negative pressure in middle ear because of ET malfunctionNegative pressure in middle ear because of ET malfunction

TM is retracted and appears redTM is retracted and appears red

Pain, high temperature, pus accumulates in middle ear Pain, high temperature, pus accumulates in middle ear mucosamucosa

In severe cases, TM ruptures due to pressure.In severe cases, TM ruptures due to pressure.

If left untreated, can progress to mastoid air cells and cause If left untreated, can progress to mastoid air cells and cause mastoiditis.mastoiditis.http://www.ent-usa.com/eardrum_and_middle_ear.htm

ConsequencesConsequences

Flat conductive hearing loss (degree Flat conductive hearing loss (degree depends on the amount of fluid)depends on the amount of fluid)

Low static complianceLow static compliance Type B tympanogramType B tympanogram Absent reflexesAbsent reflexes Absent OAEsAbsent OAEs High latencies for all ABR peaksHigh latencies for all ABR peaks

Treatment Treatment

AntibioticsAntibiotics

SurgerySurgery

Myringotomy and suctionMyringotomy and suction

Mastoidectomy (if infection has spread to Mastoidectomy (if infection has spread to mastoid region)mastoid region)

TympanoplastyTympanoplasty

PE TubesPE Tubes

http://www.pedisurg.com/PtEducENT/tube_in_TM.jpg

Complications of otitis mediaComplications of otitis media Cholesteotoma: Sac-like growth due to presence of skin in Cholesteotoma: Sac-like growth due to presence of skin in

the middle ear.the middle ear.

Dangerous, progressive, highly erosiveDangerous, progressive, highly erosive

Foul-smelling discharge (otorrhea)Foul-smelling discharge (otorrhea)

Treatment: Surgical removalTreatment: Surgical removal

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

CholesteatomaCholesteatoma

http://chicagoear.com/med_info/images_med_info/cholesteatoma.jpg

CholesteatomaCholesteatoma

http://www.earsurgery.org/images/Photo-31%20copy.jpg

CholesteatomaCholesteatoma

http://my.clevelandclinic.org/PublishingImages/Head_Neck/cholesteatoma.jpg

Facial palsyFacial palsy If erosion of bone occurs, facial nerve may be exposed. If erosion of bone occurs, facial nerve may be exposed.

Partial/Full paralysis of one side of the face.Partial/Full paralysis of one side of the face.

Treatment: SurgeryTreatment: Surgery

Eustachian tube problems Eustachian tube problems

Cause: Infections, allergies, blockage due to Cause: Infections, allergies, blockage due to overgrown adenoids, structural problems.overgrown adenoids, structural problems.

Consequences: Negative middle ear Consequences: Negative middle ear pressure, retracted TM.pressure, retracted TM.

Audiometric findings: Mild conductive Audiometric findings: Mild conductive hearing loss, normal static compliance, hearing loss, normal static compliance, type C tympanogram.type C tympanogram.

Methods to open ETMethods to open ET

Valsalva: Close nostrils and cheek and blow Valsalva: Close nostrils and cheek and blow out.out.

Toynbee: Close nostrils and swallowToynbee: Close nostrils and swallow

Complications of ET malfunction:Complications of ET malfunction:

Serous effusionSerous effusion

Mucous otitis media Mucous otitis media

OtosclerosisOtosclerosis

Causes: Hereditary in 70% of cases.Causes: Hereditary in 70% of cases.

Progressive in natureProgressive in nature

Higher incidence in women, adults.Higher incidence in women, adults.

Clinical manifestation: Spongy bone Clinical manifestation: Spongy bone formation over the stapes footplate. formation over the stapes footplate. Footplate becomes fixed in the oval window.Footplate becomes fixed in the oval window.

Other clinical signsOther clinical signs Progressive hearing lossProgressive hearing loss

TinnitusTinnitus

Difficulty hearing while chewingDifficulty hearing while chewing

Very vascular promontory, rosy glow through TM Very vascular promontory, rosy glow through TM (Schwartze sign)(Schwartze sign)

Paracusis willisii: Speech Paracusis willisii: Speech easiereasier to understand in to understand in the presence of background noise.the presence of background noise.

Audiometric findingsAudiometric findings

Low frequency conductive hearing loss Low frequency conductive hearing loss with air-bone gap.with air-bone gap.

As disease progresses, hearing loss As disease progresses, hearing loss spreads to high frequencies.spreads to high frequencies.

Bone conduction is affected, primarily at Bone conduction is affected, primarily at 2000 Hz (called Carhart’s notch).2000 Hz (called Carhart’s notch).

Type AType As s tympanogram, absent reflexestympanogram, absent reflexes

TreatmentTreatment Earlier: Surgery to free immobilized stapes footplate. Not very Earlier: Surgery to free immobilized stapes footplate. Not very

successful.successful.

Fenestration (new window created in lateral semicircular canal).Fenestration (new window created in lateral semicircular canal).

Effects of fenestration: ~ 25 dB hearing loss to total hearing loss, Effects of fenestration: ~ 25 dB hearing loss to total hearing loss, vertigo, tinnitus, poor word recognition scores, facial paralysis, vertigo, tinnitus, poor word recognition scores, facial paralysis, repeated infections of cavityrepeated infections of cavity

Stapes mobilization: Middle ear cavity exposed through incision in TM. Stapes mobilization: Middle ear cavity exposed through incision in TM.

Effects: Immediate improvement in hearing, however, refixation of Effects: Immediate improvement in hearing, however, refixation of stapes often occurred.stapes often occurred.

Most successful treatment: Stapedectomy. Replaced with prosthesisMost successful treatment: Stapedectomy. Replaced with prosthesis

Modification: StapedotomyModification: Stapedotomy

Inner earInner ear Series of interconnecting canals Series of interconnecting canals

or ‘labyrinths’ in the temporal or ‘labyrinths’ in the temporal bonebone

Two types:Two types:

Osseous Osseous

BonyBony Bigger cross-sectional areaBigger cross-sectional area Contains fluid called Contains fluid called

perilymphperilymph

MembraneousMembraneous

Soft tissueSoft tissue Situated within the bony Situated within the bony

labyrinthlabyrinth Contains fluid called Contains fluid called

endolymphendolymphhttp://research.meei.harvard.edu/Otopathology/3dmodels/download.html