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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_4455_Библиотеки_им_академика_М_И_Перельмана
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130 Disorders of the Auditory System
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aerodigestive tract is indicated to identify
associated diseases and/or the etiologic
causes for otitis media. In addition, the palate must be examined if an adenoidectomy
is being considered. Performing an adenoidectomy on a patient with a cleft palate
or a submucous cleft can lead to velopharyngeal insufficiency and nasal reflux.
Due to the low incidence of otitis
media in the adult population, the presence of unilateral effusion, without a clear
precipitating event, is a concerning finding. A thorough evaluation of the nasopharynx in these cases must be performed
to rule out a neoplasm. Appendixes 4A
through 4D provide examples of a normal
tympanic membrane, as well as eardrums
with a variety of otologic conditions.
Audiologic Management
Audiologic management is reserved for
cases in which hearing loss is present
and traditional medical management
is unsuccessful. Hearing loss typically
ranges from mild to moderate depending
on the stage of the disease. In such cases,
either traditional hearing aids, softband
bone-anchored aids, or osseointegrated
devices are highly successful. However,
long-term complications can develop if
the underlying medical condition is not
resolved, and patients should be made
aware of this possibility (Hobson et al.,
2010). Most patients with purely conductive hearing losses present with excellent
word recognition abilities (90% to 100%);
therefore, amplification will provide the
additional gain needed for everyday
functioning for patients for whom medical intervention is unsuccessful or contraindicated. These patients typically do
well with and receive benefit from their
hearing aids or devices. It should be kept
in mind that long-standing, untreated
conductive hearing loss is a form of auditory deprivation, which in some cases can
affect higher-order auditory processes. If
central auditory dysfunction secondary
to auditory deprivation is suspected, then
a central auditory processing assessment
should be completed and appropriate
management procedures implemented
(see Chapter 7, “Disorders of the Central
Auditory Nervous System”).
Medical Management
Acute otitis media can resolve spontaneously; however, the use of oral antibiotics
helps to shorten the duration of symptoms
and prevent complications. Compared
with simple observation, treatment of
acute otitis media with antibiotics results
in a 25% decrease in pain in children less
than 2 years of age (Rovers et al., 2006).
Treatment of acute otitis media with anti-
biotics — such as amoxicillin, cephalosporins, and macrolides — are directed at the
most common organisms found in the
middle ear. However, there is some concern regarding the frequent usage of antimicrobial drugs and the bacterial resistance that can result (Goossens, Ferech,
Vander Stichele, & Elseviers, 2005).
Recurrent acute otitis media is often
surgically treated with myringotomy
and PE tube placement. The 2016 American Academy of Otolaryngology-Head
and Neck Surgery (AAO-HNS) Clinical
Practice Guidelines on otitis media with
effusion have provided specific guidelines with respect to the recommendations of PE tube placement for children
with chronic bilateral otitis media. The
guidelines recommend that children
with otitis media should be monitored
in 3 to 6 months intervals until effusion
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has resolved, structural abnormalities
are identified or suspected, or a hearing
loss is diagnosed. With respect to PE tube
insertion, the guidelines recommend that
children ≥3 months of age with chronic
otitis media and documented hearing difficulties be offered the option of PE tubes.
The reader is referred to the AAO-HNS
guidelines mentioned previously for a full
review of the recommended guidelines.
The placement of the PE tube allows
for adequate aeration of the middle ear
space, preventing the accumulation of an
effusion. Tympanostomy tubes also alleviate many of the symptoms of acute otitis media when it occurs. A great variety
of tubes are available commercially that
differ in size, duration of effectiveness,
and composition. Tubes that remain in
place longer have a higher risk of leaving a tympanic membrane perforation.
Adenoidectomy can also be a key component of the treatment of otitis media. This
procedure has been shown to decrease the
morbidity of otitis media in some patients
(Gates, Avery, Prihoda, & Cooper, 1987).
This surgical procedure is typically performed in cases of persistent or recurrent
otitis media following an initial trial with
tympanostomy tubes. However, in general, adenoidectomy is not performed in
children under the age of 2 years.
Audiology
Pure-tone testing was completed using
conditioned play audiometric procedures.
Test results documented a mild conductive
hearing loss in both ears (Figure 4–3A).
Tympanometry revealed little or no compliance with normal ear canal volume
measures bilaterally and word recognition was excellent for both ears.
Medical Examination
The patient presented with normal appearing mastoids, pinnae, and ear canals;
however, evaluation of the tympanic membranes with a microscope revealed excessive purulent fluid in both middle ears.
Impression
Recurrent otitis media with effusion in
both ears.
Audiologic Recommendations
and Management
Reevaluation following medical intervention.
Medical Recommendations
and Management
Case 4–3: Otitis Media
History
This 3-year-old female was seen for an
audiologic evaluation following a failed
preschool hearing screening test. The patient’s parents reported that their daughter had a history of occasional otitis media
and a speech and language delay with no
other significant audiologic, developmental, or neurologic symptoms reported.
It was recommended that the patient
undergo bilateral PE tube placement.
Additional Comments
A postoperative audiogram revealed normal peripheral hearing bilaterally (Figure 4–3B). Ear canal volume measures
were larger in both ears than expected for
a child of this age, indicating that the PE
tubes were in place and were patent.
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A
Figure 4 –3. Pure-tone air- and bone-conduction thresholds, speech audiometry, and tympanom-
etry results for a 3-year-old with bilateral otitis media (Case 4–3). Results are shown for both preoperative testing (A) and postoperative testing (B). continues
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B
Figure 4–3. continued
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Case 4–4: Otitis Media
History
An 83-year-old male with a history of agerelated hearing loss was evaluated due to
a decrease in his hearing sensitivity and
the report of a right-sided aural fullness
following an upper respiratory infection
lasting 6 months.
Audiology
Test results indicated a mild sloping to
severe sensorineural hearing loss in the
left ear and a moderate to moderatelysevere mixed hearing loss in the right ear
(Figure 4–4A). Tympanometry revealed
normal pressure, volume, and compliance
for the left ear and reduced compliance
and negative pressure with normal volume for the right ear. Word recognition
was fair bilaterally.
Medical Recommendations
and Management
It was recommended that the patient
undergo unilateral PE tube placement
in the right ear under local anesthesia in
the office.
Additional Comments
One month following PE tube placement,
the patient’s postoperative audiogram
revealed a symmetric sensorineural hearing loss with recovery of the conductive
component in the right ear. Tympanometric testing for the right ear showed a large
volume consistent with a patent PE tube
(Figure 4–4B).
cholesteatoma
Introduction
Medical Examination
The patient presented with a normally
appearing mastoid, pinna, and ear canal
bilaterally. Otoscopic examination of the
tympanic membrane under the microscope revealed dullness with excessive
fluid for the right side, and a normal tympanic membrane on the left side.
Impression
Otitis media with effusion in the right
ear.
Audiologic Recommendations
and Management
Reevaluation following medical intervention.
Chronic otitis media is a distinct entity
from other forms of otitis media. This disease may manifest itself in the following
conditions: persistent perforation of the
tympanic membrane, erosion of the ossicles, the presence of granulation tissue in
the middle ear, and cholesteatoma. The
term, cholesteatoma, is used to describe
a collection of keratin-producing squamous epithelial cells within the middle
ear or mastoid. The term, however, is a
misnomer in that a cholesteatoma is not
a neoplasm. Johannes Müller first de-
scribed this condition in the 19th century
as “a pearly tumor” (Müller, 1838) and
presumably this label led to the coining
of the term, cholesteatoma, which continues to be the term used for this middle
ear pathology. A cholesteatoma contains
viable and nonviable squamous epithelial
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A
Figure 4–4. Pure-tone air- and bone-conduction thresholds, speech audiometry, and tympanom-
etry results for an 83-year-old male with otitis media in the right ear (Case 4–4). Results are shown
for both preoperative testing (A) and postoperative testing (B). continues
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B
Figure 4–4. continued
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cells with a blend of osteolytic enzymes,
cholesterol crystals, and keratin debris.
The middle ear is lined primarily by respiratory cuboidal epithelium,
whereas the external auditory canal is
lined by squamous epithelial cells, and
the tympanic membrane serves as a barrier between the two regions. Cholesteatomas can be either acquired or congenital.
An acquired cholesteatoma refers to the
collection of squamous epithelial cells
that collect either adjacent to or through
a compromised tympanic membrane to
affect middle ear structure and function.
There are two types of acquired cholesteatomas: primary acquired cholesteatoma,
which involves a squamous collection
within a retracted tympanic membrane
pocket, and secondary acquired cholesteatoma, which is characterized by squamous cell migration through a tympanic
membrane perforation into the middle
ear. A congenital cholesteatoma refers to
the presence of squamous cells within the
middle ear with no history of tympanic
membrane perforation, otitis media, or
Eustachian tube dysfunction (Canalis &
Lambert, 2000). Acquired cholesteatomas
are much more common than congenital
cholesteatomas.
Symptoms
Primary cholesteatomas are frequently
clinically silent until they reach a size large
enough to impinge on the ossicles, causing a conductive hearing loss. A secondary
cholesteatoma with bacterial colonization
leads to persistent foul-smelling otorrhea
due to the presence of chronic inflammation and infection. As a retraction pocket
with cholesteatomatous debris deepens in
the middle ear space and extends into the
mastoid, pain may be experienced and the
ossicles may be eroded causing conductive hearing loss. Erosion of bone adjacent
to the middle ear can lead to significant
complications. An expanding cholesteatoma may damage the facial nerve along
its course within the temporal bone, leading to facial paralysis. In addition, a fistula
of the labyrinth, specifically in the horizontal semicircular canal, may occur with
resulting vertigo or dizziness. Finally,
erosion of tegmen bone or an intravascular spread of colonized bacteria may lead
to meningitis, brain abscess, or subdural empyema. These conditions may be
heralded by neurologic symptoms, such
as mental status changes, headache, and
fever (Penido Nde et al., 2005).
Incidence and Prevalence
Otitis media is a ubiquitous disease;
however, chronic otitis media with cholesteatoma is significantly less common.
Congenital cholesteatoma occurs at an
incidence rate of 0.12 per 100,000 (Tos,
2000). The annual incidence of acquired
cholesteatoma in Caucasians has been
found to be about 3 per 100,000 in children
and 9.2 per 100,000 for people of all ages
with a male predominance (Olszewska
et al., 2004). Regarding the type of cholesteatoma, the mean age of diagnosis for
children with congenital cholesteatoma is
5.6 years, and those with acquired cholesteatoma is 9.7 years (Nelson et al., 2002).
Etiology and Pathology
A congenital cholesteatoma is believed to
be a remnant of embryonic epithelial cell
nests trapped in the middle ear during
development. Chronic otitis media with
secondary cholesteatoma is a result of
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long-term Eustachian tube dysfunction.
Recurrent infections of the middle ear
space can irreversibly change the middle
ear mucosa (Tos & Bak-Pedersen, 1972).
This can change the nature of mucosa
from a cuboidal respiratory epithelium
to a squamous epithelium, which can
deposit keratin debris in the middle ear,
according to a metaplasia theory of cholesteatoma development (Sadé, Babiacki,
& Pinkus, 1983).
Another mechanism of cholesteatoma
formation is invagination of squamous
epithelium within a retracted tympanic
membrane. Chronic inflammation in the
middle ear can lead to weakening of the
fibrous layer of the tympanic membrane
(Abramson & Huang, 1977). This weakened membrane can be easily retracted by
negative middle ear pressure. The superior region of the tympanic membrane,
referred to as the pars flaccida, contains a
higher proportion of elastin and is the most
frequently retracted area. Squamous epithelium of the external layer of a healthy
tympanic membrane typically migrates
outward in a medial-to-lateral direction
and sloughs in the external auditory canal,
but when a membrane retraction develops, this sloughing epithelium, keratin
debris, and a host of bacteria are trapped
in this pocket. This matrix of debris leads
to further inflammation and may cause
the formation of granulation tissue.
The bacteria in a cholesteatoma are
diverse and recalcitrant to medical management. The primary organism of chronic
otitis media is Pseudomonas aeruginosa.
Pathogens such as Staphylococcus aureus,
Escherichia coli, Streptococcus epidermidis,
as well as a mix of anaerobes also may
be found within a cholesteatoma. Moisture within the pocket and the external
ear create an ideal environment for bacterial growth. This pocket has a tendency
to expand and tunnel into the middle ear
and erode the bone that it comes into contact with by several different mechanisms,
including mechanical pressure destruction, biochemical degradation from bacterial toxins or granulation tissue, and
cellular absorption of bone by osteoclasts
(Canalis & Lambert, 2000). The ossicles
are frequently eroded by an expanding
cholesteatoma. Other sites of bony erosion
include the bone covering the horizontal
portion of the facial nerve and the tegmen tympani and/or the tegmen mastoideum, which separate the middle ear and
mastoid, respectively, from dura (Amar,
Wishahi, & Zakhary, 1996).
Chronic marginal perforations of
the tympanic membrane can result in
squamous cell migration into the middle
ear and the development of a secondary
acquired cholesteatoma. In addition, traumatic perforation of the tympanic membrane, such as a blast injury or temporal
bone fracture, may deposit keratin-forming squamous cells within the middle ear
that may result in a secondary acquired
cholesteatoma (Canalis & Lambert, 2000).
Site of Lesion
Cholesteatomas tend to develop in predictable locations in the middle ear and
temporal bone. Embryonic cell nests may
pathologically remain in the middle ear
during development leading to a congenital cholesteatoma. Within the middle ear,
this usually occurs in the anterior mesotympanum or the protympanum. A congenital cholesteatoma may also occur
within the petrous apex of the temporal
bone and usually is referred to as an epidermoid cyst.
The most common location of a primary acquired cholesteatoma is the pos-
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terior epitympanic space, also known as
Prussak’s space (Palva, Ramsay, & Böhling, 1996). A cholesteatoma in this region
extends posteriorly into the mastoid by
way of the antrum. In this confined space,
the head of the malleus and the short process of the incus can easily be eroded by
the disease process. The anterior aspect
of the epitympanic space can also be
involved by a cholesteatoma, which typically invades the mesotympanum anterior
to the handle of the malleus. The posterior
aspect of the pars tensa also may become
retracted and result in a primary acquired
cholesteatoma that extends into the posterior mesotympanum. In the same region,
perforation of the tympanic membrane
may be the site of development of a secondary acquired cholesteatoma. Cholesteatomas can also extend into the petrous
portion of the temporal bone. Appendix 4E presents an example of tympanic
membrane with a cholesteatoma.
Audiology
The audiologic examination for a patient
with a cholesteatoma should involve routine tympanometry to evaluate middle ear
function and comprehensive audiometry
to determine hearing sensitivity. There
is significant variability with respect to
tympanometric results in patients with
cholesteatoma, with this variability dependent on the degree of ossicular chain
involvement. For cases with very little
ossicular chain involvement, normal
pressure, volume, and compliance may
be observed. However, once the ossicular chain becomes involved, compliance
is significantly reduced. Patients with no
underlying sensorineural involvement
generally present with a purely conductive hearing loss on the affected side. In
rare cases, patients will present with normal peripheral hearing sensitivity (see
Jerger & Jerger, 1981).
Medical Examination
A vital aspect of successful diagnosis
and treatment of cholesteatoma involves
obtaining a detailed otologic history.
Documentation must be made of the history of otitis media as well as tympanostomy tube placement, which may indicate a long history of Eustachian tube
dysfunction. The duration and character
of otorrhea is also an important aspect of
the otologic history. Due to the chronic
nature and high recurrence rate of cholesteatomas, these patients may have
had multiple operations. Previous surgical reports can provide vital clues to the
initial presentation of the disease, as well
as to the extent of bone erosion caused by
the disease processes. Inquiries should be
made regarding a history of hearing loss,
otalgia, tinnitus, and vertigo.
A thorough head and neck examination should accompany a careful otologic
examination. Otomicroscopy is used to
thoroughly clean the external canal of
drainage and debris. In early stages of
chronic otitis media, the epitympanic area
of the tympanic membrane may have a
shallow retraction pocket. Determination
of the depth of the pocket and the presence of keratin debris should be made.
As this pocket expands, the depth of the
pocket cannot be visualized and successful removal of all of the debris is uncertain. The debris within the pocket may
be of differing consistencies and color;
however, classically, a cholesteatoma
looks like white cake icing. Granulation
tissue may be present in this region. If it
is present, it is beefy red in color and has
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