hearing loss
TRANSCRIPT
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Hearing Loss
Dr. Utkal MishraPG (ENT)
VSS MEDICAL COLLEGE,BURLA
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CLASSIFICATION
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CONDUCTIVE HEARING LOSS
CAUSESACQUIRED
WAXFOREIGN BODY
FURUNCLEATRESIA OF EAR CANAL
PERFORATION OF TMFLUID IN MIDDLE EARMASS IN MIDDLE EAR
EUSTACHIAN TUBE BLOCKAGEOSSICULAR DISRUPTION
FIXATION OF STAPES
CONGENITALMEATAL ATRESIA
FIXATION OF MALLEUS FIXATION OF STAPES
OSSICULAR DISCONTINUITYCONGENITAL CHOLESTEATOMA
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Characteristics of Conductive hearing loss
Negative Rinnie Test BC > AC Weber Lateralized to poorer ear Normal ABC Low frequencies affected more PTA – BC better than AC with A-B gap Loss is not more than 60 dB Speech discrimination is good.
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Hearing Loss seen in different lesions
Complete Obstruction of ear canal – 30dB TM Perforation – 10 – 40 dB Ossicular disruption with intact TM – 54dB Ossicular disruption with TM Perforation – 38
dB Malleus Fixation – 10-25 dB Closure of Oval Window – 60dB
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Management
Removal of canal obstruct ion Removal of fluid Removal of mass Stapedectomy Tympanoplasty Hear ing A id
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SENSORINEURAL HEARING LOSSCAUSESACQUIRED
WARDENBURG SYNDROMEUSHER SYNDROMEALPORT SYNDROME
PENDRED SYNDROMECROUZON SYNDROME
LABYRINTHITISTEMPORAL BONE FRACTURE
NOISE INDUCED HEARING LOSSOTOTOXIC DRUGS
PRESBYCUSISACOUSTIC NEUROMA
DM, HTN, MS, HYPOTHYROID
CONGENITALSHIEBE DYSPLASIA (cochlea/ saccule)
ALEXANDER DYSPLASIA (basal turn of membranous cochlea)
TORCHES INFECTIONDRUGS
RADIATION
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Characteristics of Sensorineural hearing loss
Positive Rinnie Test AC > BC Weber Lateralized to better ear Reduced ABC & Schwabach High frequencies affected more PTA – AC better than BC with no A-B gap Loss is more than 60 dB Speech discrimination is poor. Difficulty hearing in presence of noise.
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OTOTOXICITY AMINOGLYCOSIDES – VESTIBULOTOXIC (type-1 hair cell) – Strepto /
Genta / Tobra
COCHLEOTOXIC (outer hair cell) – Neo / Kana / Amika
LOOP DIURETICS – (edema of stria vascularis) – Furosemide, Ethacrynic acid
SALICYLATES QUININE – vasospasm of stria vascularis CHLOROQUINE CYTOTOXIC DRUGS (outer hair cells) – Nitrogen Mustard, Cisplatin,
Carboplatin DESFERRIOXAMINE TOPICAL EAR DROPS – Chlorhexidine, Gentamycin, Polymyxin-B
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NOISE TRAUMA2 TYPES
NOISE INDUCED HEARING LOSSTEMPORARY THRESHOLD SHIFT
(Immediate loss of hearing just after exposure to noise which is reversible)
PERMANENT THRESHOLD SHIFT(Permanent hearing loss)
ACOUSTIC TRAUMAPermanent damage to hearing caused by single
brief exposure to sound > 140 Db
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NOISE TRAUMA
Frequency causing more damage – 2000 – 3000 Hz.
Maximum Safe Limit – 90 dB noise, 8h a day, 5 days a week
PTA – Typical Notch at 4kHz both for AC & BC.
Damage to hair cells start at Basal Coil of Cochlea
Outer Hair cells are first to be affected.
Maximum permissible impulse noise – 140dB
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SUDDEN HEARING LOSS
DEFINATION – 30 dB or more SNHL at least 3 contiguous frequencies occuring
within a period of 3 days or less.
Mostly UNILATERAL.
Prognosis – 50 % spontaneous recovery within 15 days.
AETIOLOGY –
1. IDIOPATHIC - Viral, Vascular, Rupture of Cochlear membranes.
2. HEAD INJURY
3. MENIERE’S DISEASE
4. OTOTOXIC DRUGS
5. HEAMORHAGE/ THROMBOSIS OF LABYRINTHINE A.
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SUDDEN HEARING LOSS MANAGEMENT
1. Bed Rest
2. Oral Steroid – Prednisolone 60mg O.D. morning dose for 1wk
3. Carbogen (5% CO2 + 95% O2) Inhalation
4. Vasodilators
5. Low salt diet & Diuretic
6. Intratympanic Steroid Therapy
7. Low molecular weight Dextran
8. Hyperbaric Oxygen Thearpy
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PRESBYCUSIS Physiological SNHL after 65 yrs age.
4 Types –
1. Sensory – Degeneration of Organ of Corti
Speech discrimination good.
2. Neural - Degeneration of cells of Spiral Ganglion
Speech discrimination poor
3. Strial - Atrophy of Stria vascularis
Speech discrimination good.
4. Cochlear Conductive – Stiffening of Basillar membrane
Recruitment Phenomenon – Positive
Difficulty hearing in presence of background noise
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NONORGANIC HEARING LOSS Malingering / Psychogenic
TESTS –
1. PTA - Inconsistent results (>5 dB) on repeatation
Absence of shadow curve of BC
2. SRT – Better than 10 dB than PTA
3. Stenger Test – Negative
4. Stapedial Reflex - Positive
2 vibrating tuning forks of 512 Hz. Placed 25 cm from both ear with patient blindfolded.
Patient will claim to hear it in normal ear
Now bring the deaf side TF closer
Now he will deny hearing anything
True Deafness – still hears on Normal side
No deafness – Hears on closer side
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