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Hearing disorders of the middle ear

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Presentation on theme: "Hearing disorders of the middle ear"— Presentation transcript:

1 Hearing disorders of the middle ear
Tympanic membrane: Perforations Tympanosclerosis: Thickening/Scarring 1 1


3 TM Perforation

4 TM Perforation

5 In some cases, spontaneous recovery (depends on location)
Consequences Mild hearing loss Treatment In some cases, spontaneous recovery (depends on location) Myringoplasty: Surgical reconstruction 5 5

6 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 6 6

7 TM Retraction

8 Acute OM

9 Acute OM

10 Acute OM

11 Possible mechanisms Through ruptured tympanic membrane
Through Eustachian tube Through blood 11 11

12 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. 12 12 12

13 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 13 13 13

14 Treatment Antibiotics Surgery Myringotomy and suction
Mastoidectomy (if infection has spread to mastoid region) Tympanoplasty 14 14 14

15 PE Tubes

16 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 16 16 16

17 Cholesteatoma

18 Cholesteatoma

19 Cholesteatoma

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

21 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. 21 21

22 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 22 22

23 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. 23 23

24 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. 24 24

25 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 Carhart’s notch). Type As tympanogram, absent reflexes 25 25

26 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 26 26

27 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

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