Transcript Document
TOPIC
2
CAUSES OF HEARING
IMPAIRMENT
Outer and Middle Ear Disorders
Structural defects due to embryologic
malformations
Structural changes secondary to
infection or trauma
Outer Ear Disorders
Microtia and atresia
Microtia
“an abnormal smallness of the auricle”
Atresia
“the absence of
an opening of
the external
canal”
Outer Ear Disorders
Microtia and atresia
Impacted cerumen
Perforation of the tympanic membrane
Perforation of the TM
n
An example of the audiogram illustrating the flat,
mild, conductive hearing loss that can occur with a
perforated tympanic membrane
Outer Ear Disorders
Microtia and atresia
Impacted cerumen
Perforation of the tympanic membrane
Other
Middle Ear Disorders
Otitis Media
Most common
cause of transient
conductive hearing
loss in children
Inflamation of the
middle ear
Caused by
eustachian tube
failure
Otitis Media
n
Three examples of
the usual
characteristics of a
conductive hearing
loss arising from
otitis media
Ways to Classify Otitis Media
With or without effusion
Fluid type
Serous
Suppurative
Mucoid
Ways to Classify Otitis Media
With or without effusion
Fluid type
Duration
Acute
Chronic
Subacute
Persistent
Recurrent
Otitis Media Facts
76-95% of all kids will have one episode of OM by
age 6
Prevalence is highest during the first two years of life
50% of all kids with one episode before their first
birthday will have 6 or more bouts within two years
Most episodes occur in winter and spring
Risk factors
Cleft palate
Down syndrome
Native Americans
Urban poor
Day care
Secondhand smoke
Middle Ear Disorders
Otitis media
Otosclerosis
Otosclerosis
“a bone disorder that affects the stapes
and the bony labyrinth of the inner ear.
The disease process is characterized by
resorption of bone and new spongy
formation around the stapes and oval
window”
Otosclerosis
Facts:
Hereditary
Women are more likely
to develop the disorder
Usually bilateral
progressive
Middle Ear Disorders
Otitis media
Otosclerosis
Cholesteatoma
Cholesteatoma
“an epithelial pocket that forms on the
tympanic membrane. Once the pocket
forms, the normal shedding of
epithelium results in growth of the
tumor”
Middle Ear Disorders
Otitis media
Otosclerosis
Cholesteatoma
Other
Physical trauma
Physical Trauma of the Middle
Ear
Here’s an example of
an audiogram
resulting from
disarticulation of the
ossicular chain
Middle Ear Disorders
Otitis media
Otosclerosis
Cholesteatoma
Other
Physical trauma
Barotrauma
Middle ear tumors
Glomus tumor
Cochlear Disorders
Syndromes and inherited disorders
Syndromic disorders
Nonsyndromal disorders
Syndromes and Inherited Disorders Resulting in
Sensorineural Hearing Loss
Types of Nonsyndromic
Disorders
Dominant
Dominant progressive
Dominant progressive with adult onset
Recessive hereditary SNHL
X-linked
Cochlear Disorders
Syndromes and inherited disorders
Noise induced hearing loss
Noise Induced Hearing Loss
The degree of SNHL depends on
The intensity of the noise
The spectral composition of the noise
The duration of exposure
Individual susceptibility
OSHA Damage Risk Criteria
Noise Induced SNHL
Noise notch
Cummulative
Progressive
Cochlear Disorders
Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Infections
Congenital
Cytomegalovirus
HIV
Rubella
Syphilis
Toxoplasmosis
Infections
Acquired
Herpes Zooster Oticus (Chicken Pox)
Mumps
Syphilis
Cochlear Disorders
Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Ototoxicity
Some antibiotics that are often ototoxic:
Amikacin
Dihydrostreptomycin
Garamycin
Gentamicin
Kanamycin
Neomycin
Netilmicin
Streptomycin
Tobramycin
Viomycin
Ototoxicity
Chemotherapy
Carboplatin
Cisplatin
Drugs that cause reversible hearing loss
Quinine
Salicylates (aspirin)
Loop diuretics
Drugs that may be harmful during pregnancy
Accutane
Dilantin
Quinine
Thalidomide
Cochlear Disorders
Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Meniere’s Disease
Meniere’s Disease
Symptoms
Tinnitus
Vertigo
Unilateral
sensorineural
hearing loss
Cochlear Disorders
Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Meniere’s Disease
Presbycusis
Presbycusis
Central Auditory Disorders
VIII Nerve tumors
Other diseases of the VIII Nerve
Neural disorders
Brain Stem disorders
Cochlear neuritis
Diabetes mellitus
Infarcts
Gliomas
Multiple sclerosis
Temporal Lobe disorders