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4 Medical Management of Hearing Loss in Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
4 Medical Management of Hearing Loss in Children
Brian A. Walker, David L. Horn, and Jay T. Rubinstein
Summary
This chapter contains a basic outline of the management of
pediatric hearing loss from the perspective of physicians. The
benefit of a team approach to pediatric hearing loss is discussed.
Common medical etiologies of hearing loss are described.
Diagnostic testing methods, including genetic testing, laboratory
testing, and medical imaging, are presented within the context
of each diagnosis. A general overview of medical and surgical
treatment for hearing loss is introduced, with special emphasis
on cochlear implantation.
Keywords
medicine, history, physical exam, treatment, etiologies, imaging,
computed tomography, magnetic resonance imaging, cochlear
implant
Key Points
Accurate classication of the type of a child’s hearing loss is
•
essential to the medical workup and treatment of the auditory system.
A thorough medical history is a critical component of the
•
medical management of childhood hearing loss.
Middle ear dysfunction and disorders are common in child-
•
hood, and expeditious and eective medical assessment and
management are essential in order to support the child’s
speech-language and auditory development.
Medical assessment may include screening for congenital
•
infections, diagnostic imaging, genetic assessment, etc.
Many pediatric auditory disorders can be managed through
•
pharmacologic and surgical intervention.
Implantable hearing technologies, such as osseointegrated
•
auditory implants and cochlear implants, are benecial for
many children with hearing loss.
4.1 Medicine and Pediatric
risk to experience psychosocial diculties, limitations of daily
functioning, and diminished employment opportunities in adult
6, 7,8
However, studies have shown that if identified and treated
life.
early, such disadvantages are preventable; this finding led to the
implementation of universal newborn hearing screening in the
early 1990s.
With earlier identification of pediatric HL came an increased
emphasis on its prompt diagnosis and treatment. Accordingly,
the Joint Committee on Infant Hearing (JCIH) developed
guidelines on the implementation of “medical homes” to
manage the care of such patients.10 The medical home is led
by the child’s primary care provider (a pediatrician), who
manages the patient’s basic health needs and provides referrals
to other health care professionals (audiologists, speech and
language pathologists, otolaryngologists, genetic counselors,
etc.) depending on the needs of the child. Most importantly,
the pediatrician pays close attention to the concerns of the
caregivers while routinely monitoring the global development
of the child over the first few years of life for any signs of speech
or language delay, which may indicate the need for referral for
audiology evaluation.
The care for children with HL requires a multidisciplinary team
of healthcare professionals. Medicine’s role on this team is primarily that of pinpointing the diagnosis, identifying the appropriate
medical intervention, determining whether medical intervention
is necessary, and intervening when appropriate. Of necessity, these
steps involve input from all other members of the child’s health
care team, the child’s parents, and, whenever possible, the child.
In addition to the pediatrician, the otolaryngologist is a physician
who has received specific training in the diagnosis and treatment of
pediatric ear disease and disability and whose responsibility it is to
evaluate for otologic treatment and intervention.
This chapter represents a brief introduction to the medical
approach and management of pediatric HL. The first section deals
primarily with the physician’s approach to the diagnosis and
treatment of pediatric HL, and references are made to specific
etiologies as they pertain to this approach. The second section
expounds on the treatments mentioned, with special emphasis
on the surgical management of pediatric HL, and ends in a brief
summary.
3,9
10
Hearing Loss
Congenital hearing loss (HL) occurs in 2 to 3 per 1,000 births,
making it the most common sensory birth defect.
alence increases throughout childhood, reaching 2.7 per 1,000
and 3.5 per 1,000 by 5 years and adolescence, respectively.3 In
addition to congenital HL, 80% of children experience a tem-
porary conductive hearing loss (CHL) at some time as a result
of middle ear infection by 4 years of age.4 If left untreated,
prolonged HL results in striking speech, language, and cognitive
developmental delays.5 As a result, these children are at greater
1,2
This prev-
4.2 Medical Diagnosis of Pediatric
Hearing Loss
4.2.1 Classication of Hearing Loss
Accurate classification of the type of HL is essential to its medical
workup and treatment. Conductive, sensorineural, mixed, and
retrocochlear are all possible forms of HL, and each represents
the eects of disease or injury on a particular part of the auditory
system. This well-known classification scheme is useful not only
41
I Hearing Loss: Essential Information
Autosomal dominant
X-Linked
recessive
X-Linked
dominant
50% Affected
50% Affected
Affected daughters
Unaffected sons
50% Affected daughters
& 50% Affected sons
50% Carriers
50% Carriers
25%
Affected
25%
"Free"
"Skipped generation":
Carrier daughters
Unaffected sons
Autosomal recessive
CC
CC
C
CC
C
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
to guide the physician’s investigation to the anatomic location
where the etiology may reside but also to dictate which medical
and surgical treatments are available to help restore or improve
the child’s hearing. (For more information regarding auditory
neuropathy spectrum disorder and central auditory processing
disorder see Chapters 16 and 33.)
4.2.2 General Approach to Pediatric
History
A thorough medical history is essential when a child is brought
in with concerns of HL and should ideally include the following:
Histor y of current HL: When did the loss begin? Progressive,
•
transient, or chronic? Bilateral or unilateral? Complaints of tinnitus/vertigo? Noise exposure? Recent trauma? When possible,
results of newborn hearing screening should be confirmed.
Medical history: Previous medical diagnoses or surgeries?
•
Previous issues with the child’s vision, heart, kidneys, thyroid?
Exposure to ototoxic medications? Recurrent ear infections?
History of meningitis? Concurrent vestibular symptoms?
Perform full review of systems.
Birth history: Prematurity or intrauterine growth restriction?
•
Hyperbilirubinemia necessitating therapy? Maternal history
of cytomegalovirus (CMV), syphilis, rubella, or toxoplasmosis?
Maternal vaccination status? Maternal illicit drug usage?
Required stay in the neonatal intensive care unit?
Family history: Any member of either parent’s family with HL?
•
Any history of syndromic diagnoses? Any history of sudden
death at an early age? Congenital cardiac, renal, or craniofacial anomalies? Progressive blindness? Preferably obtain
three-generation pedigree chart (Fig . 4.1).
Developmental history: Does the child startle in response to
•
loud sounds? Does the child respond to his/her name? Did the
child walk at the expected age? Does the child babble or speak
as appropriate for age?
These questions aid the physician in developing a dierential
diagnosis, guiding diagnostic testing, and helping to identify
etiologies that may not be identifiable at presentation via physical
exam, lab tests, or imaging. Such etiologies include hyperbilirubinemia at birth requiring exchange transfusion; prematurity or
int
rauterine growth restriction; excessive noise exposure; heavy
metal exposure; ototoxic medication exposure; prior episode of
meningitis; and maternal exposure to infectious etiologies.
While it is currently unknown why preterm birth is associated
with HL, studies have shown that the prevalence of HL increases
with decreasing gestation and decreasing birth weight.
Neonatal hyperbilirubinemia (which manifests as jaundice) is a
relatively common occurrence in newborns, and the risk of sensorineural HL (SNHL) from hyperbilirubinemia is greatest in those
infants who require exchange transfusion.13 Because HL due to
these etiologies is the result of previous exposure, these patients
may still benefit from cochlear implants (CIs) if insucient benefit
is obtained with hearing aids.
Hearing Loss Diagnosis
Fig. 4.1 Example pedigree diagrams for autosomal dominant,
autosomal recessive, X-linked recessive, and X-linked dominant inheritance. Circles = females; squares = males; open symbols = free from
bnormal gene; lled symbol = aected carriers of abnormal gene; C
a
= unaected carriers of abnormal gene. (Used with permission from
Gelfand SA. Essentials of Audiology, 4th ed. New York, NY: Thieme
Publishers; 2016.)
Bacterial meningitis is the most common cause of acquired HL
14
in childhood.
The type of bacteria causing the infection depends
on the age, health status, vaccination and exposure history of the
child but the most common causes are Group B Streptococcus,
Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus
inuenzae, Listeria monocytogenes, and Escherichia coli.
loss from bacterial meningitis results from inammation or direct
infection of the inner ear or cochlear nerve (branch of cranial
nerve VIII), resulting in permanent damage.16 In order to prevent
bacterial meningitis, children are routinely vaccinated with the
PCV13 and Hib vaccines (which work against S. pneumoniae and
H. inuenzae Type B, respectively). If the child is at increased risk
of bacterial meningitis (such as those with CI or inner ear anomaly
11,12
that communicates with the cerebrospinal uid of the central nervous system), they are also advised to receive the PPSV23 vaccine,
whic
h adds additional pneumococcal coverage.17 While helping to
prevent many cases of bacterial meningitis, these vaccines do not
prevent it entirely. When HL does occur, hearing aids or CI may
be utilized to provide access to sound. CI surgery is occasionally
done urgently in the case of bacterial meningitis because cochlear
ossification may occur soon after meningitis, after which it can be
15
Hearing
42
4 Medical Management of Hearing Loss in Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
extremely dicult to place an implant’s electrode in a position
that would provide benefit to the patient.
Exposures to various ototoxic substances and stimuli may also
result in SNHL. The most common sources are excessive noise and
medications. The most commonly implicated medications that
can cause HL include aminoglycoside antibiotics, intravenous
loop diuretics, and chemotherapeutics. These medications can
also have vestibulotoxic eects; thus, any vestibular complaints
should also be elicited. Other medications, such as salicylates
(aspirin), can cause HL when taken in high doses, yet the loss is
reversed when the medication is discontinued. The treatment for
both of these types of HL is to cease exposure.
18,19
Pitfall
Children undergoing CI should receive appropriate vaccinations
to protect against bacterial meningitis.
Pearl
Routine vaccinations are essential to preventing bacterial meningitis and concomitant HL.
Physical Examination
In addition to a thorough medical history, all children presenting
with HL should receive both a general and an otologic physical
exam. The general exam has the utility of identifying syndromic
etiologies, which often (but not always) manifest themselves
as external phenotypes. One study showed that etiology was
identified via physical exam in 43% of 114 referred patients
with HL.20 Examples include the white forelock of hair, heterochromia, and dystopia canthorum (pseudohypertelorism) of
Waardenburg syndrome; the enlarged thyroid found in Pendred
syndrome; the congenital neck and auricular anomalies found
in branchio-oto-renal (BOR) syndrome; the atypical facies seen
in trisomy 21 (Down syndrome); or cleft palate, micrognathia,
facial hypoplasia, and hypermobility of joints in Stickler syndrome. If general evaluation raises concerns for a syndromic
diagnosis, it is important to refer the patient to other services
(such as a medical geneticist), in addition to discussing genetic
testing and addressing the HL. (See Chapter 3 for genetic causes
of pediatric HL.)
The otologic exam includes examination of the external and
middle ear and auditory testing. A proper ear exam includes investigation of the auricle, external auditory canal (EAC), and tympanic membrane, both generally and via otoscope. The auricle’s
, position, and regularity are all essential to note in addition
shape
to evidence of preauricular pits or tags. These are commonly the
result of embryonic developmental abnormalities that may or may
not be associated with a syndromic diagnosis.21 Malformations
at this level of the ear can be indicative of not only internal ear
malformations that may result in HL, but also malformations of
other organ systems such as the kidneys, eyes, and skeleton. As
with other diagnoses previously discussed, patients with malformations of the ear may require referral to medical genetics and
genetic testing to identify the etiology properly (Fig. 4.2).
The EAC is evaluated both grossly via direct visual inspection
and more finely via otoscope. During this part of the exam it is
important to note the presence of the canal, its caliber, its contents,
any evidence of inammation or discharge, and any irregularities.
Etiologies of HL identified by this portion of the exam are due to
obstruction and generally result in conductive hearing loss. Such
obstructions include EAC atresia, otitis externa, osteomas, exostoses, cerumen impaction, webs or pits, and foreign bodies (see
Chapter 2 for detailed discussion). These etiologies are diverse in
their pathogenesis and onset and, as such, merit dierent workups and treatment. For example, surgical intervention for children
with certain unilateral causes of CHL might be delayed longer than
for children with bilateral involvement, particularly if speech and
language development are proceeding well with amplification
and assistive listening devices such as school FM systems.
EAC atresia and developmental webs or pits of the EAC may
require computed tomography (CT) imaging prior to surgery to
establish the extent of the malformation and the presence of a
Pearl
The history and physical examination are essential to avoiding
unnecessary tests and imaging while maximizing their diagnostic
yield.
Fig. 4.2 Microtia. (Used with permission from Pensak ML, Choo DI.
Clinical Otology, 4th ed. New York, NY: Thieme Publishers; 2015.)
43
I Hearing Loss: Essential Information
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
normal inner ear. If the anatomy is found to be favorable, reconstruction is routinely performed. Atresia repair typically involves
creation of an EAC and tympanic membrane with middle ear
ossiculoplasty and results in postoperative speech perception
thresholds of ≤ 35 dB in 45 to 89% of patients.22 In the case of
unilateral atresia with a normal hearing contralateral ear, reconstruction may be postponed until desired by the patient/family or
until compliance with postoperative care is likely. In these cases,
it is sucient to augment hearing via conventional hearing aids
or bone conduction devices, with close follow-up of hearing and
spoken language development by audiologists and speech-language pathologists/auditory verbal practitioners.
23,24
Surgical
intervention to create a new EAC in a child with aural atresia is
typically delayed until early school-age while the child uses a
bone-conduction hearing aid in the interim.
The other causes of HL that may be revealed during the exam
include exostoses, osteomas, cerumen impaction, and foreign
body. Cerumen impaction and foreign body are both fairly frequent
among the pediatric population and can both be reliably treated in
the clinic via manual extraction. Exostoses or osteomas have been
shown to be amenable to surgical removal if symptomatic but can
otherwise be closely monitored and removed only in the event
they do become symptomatic.
25,26
Lastly, otitis externa can cause HL via the buildup of infectious
debris in the ear in combination with EAC inammation and
swelling. Given that this represents an infectious process of the
EAC, it is commonly treated with débridement and various combinations of topical antibiotics, antiseptics, glucocorticoids, and
acidifying solutions, with the combination being dictated by the
severity of the infection and choice of the physician.
After evaluation of the EAC, it is necessary to evaluate the
tympanic membrane because it can be used as an indication of the
status of the middle ear. Important aspects to note are its position,
translucency, color, and the visibility of the ossicles through the
membrane. Etiologies of HL that are identifiable via inspection of
the tympanic membrane include perforation, otitis media, and
middle ear eusion. In fact, otitis media with eusion represents
the most common cause of acquired childhood HL.27 The risk of such
eusions is that serial or chronic eusions can erode the auditory
ossicles, resulting in permanent CHL. It is imperative that children
with eusions be closely monitored until the eusion resolves
completely. This monitoring is to ensure that erosion of the ossicles
does not occur but also to prove that no other etiology may be
underlying the child’s HL and that the HL was not falsely attributed
to the eusion. Inversely, if a child presents with complaints of HL
and has evidence of middle ear eusion, it is essential to charac-
terize the type of HL properly (in case the child is presenting with
mixed hearing loss) and exclude other possible etiologies so as not
to delay the treatment of more serious causes of HL. Otitis media
and its associated eusion are associated with tympanic membrane
visual changes such as an overall change in color or translucency,
hypervascularity, erythema, or bulging. To verify the suspicion that
there is increased pressure in the middle ear cavity, pneumatic
otoscopy can be used to view whether the tympanic membrane
deects normally in response to pneumatic compression.
For young children without a history of recurrent or chronic
otitis media and mild symptoms for less than 72 hours, it is
permissible to observe and follow up if the symptoms worsen,
because much of acute otitis media represents a viral etiology
that is not amenable to antibiotic therapy and will resolve spontaneously. In the case that the child does have an extensive history
of such infections, an infection that lasts longer than 72 hours, or
an SNHL, antibiotic therapy is initiated without delay.
Middle ear eusion is a common sequela of a middle ear infec-
tion but can also occur spontaneously in some children. While 90%
of eusions are thought to resolve spontaneously over the course
of 3 months, the remaining 10% are at risk of longer-standing HL.28
A proven surgical solution for these children is tympanostomy
tube placement, which relieves the buildup of uid via communication between the EAC and middle ear (Fig. 4.3).
Tympanic membrane perforation can occur when a child is
exposed to loud noises or via direct trauma. The severity of HL
associated with a perforated tympanic membrane correlates with
the size and location of the perforation.
29,30,31
One subsequent risk
of tympanic membrane perforation, particularly for marginal
perforations involving the annulus, is the eventual development
of an acquired cholesteatoma that can itself cause conductive
hearing loss. An acquired cholesteatoma is an overgrowth of
a b c
Fig. 4.3 Various tympanostomy tubes after placement into tympanic membrane. (Used with permission from Pensak ML, Choo DI. Clinical Otology,
4th ed. New York, NY: Thieme Publishers; 2015.)
44
4 Medical Management of Hearing Loss in Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
keratinizing squamous epithelium from the tympanic membrane
that enlarges and impinges on various middle ear structures
such as the eustachian tube (causing middle ear eusion) or the
ossicles (causing disruption), resulting in HL.32 When identified,
these must be treated surgically to prevent erosion of the ossicles,
inner ear damage, facial paralysis, and intracranial infection.
Cholesteatoma management in children may require multiple
surgical procedures to avoid recurrent disease.
Pearl
Children with tympanic membrane perforation should be closely
monitored for potential cholesteatoma development.
The last portion of the otologic exam consists of a brief hearing
test performed by the provider at the bedside. (This is not a substitute for a complete audiologic evaluation but instead serves as a
omplement.) The Weber and Rinne tests are complementary and
c
are administered together (Table 4.1). The Weber test is administered by placing the base of a vibrating tuning fork over the midline
of the face or skull and asking the patient to indicate to which ear
the sound localizes. This ear may represent CHL in the ipsilateral
ear or SNHL in the opposite ear. The Rinne test is then performed
by placing a vibrating tuning fork next to the patient’s ear until the
patient can no longer hear the vibration and then transitioning
the fork’s base to the mastoid of the ipsilateral skull. If the sound
is louder when the fork is in contact with the mastoid, suspicion
is raised for ipsilateral CHL (because air conduction is better than
bone conduction in a normal-hearing individual). These tests are
useful and easy to administer during an oce exam in children
old enough to understand the instructions (typically by 5 years
of age) and help with the preliminary identification of etiology.
Additionally, these tuning fork tests can be administered at vari-
ous frequencies to complement audiometric findings (Table 4.1).
that up to 70% of children with profound SNHL simultaneously
have vestibular dysfunction.33 Common tests of vestibular function include the head-thrust test and gait observance. Because the
vestibular system is responsible for balance, any abnormality may
result in an uncoordinated or ataxic gait that is easily identified
simply by instructing the patient to walk in a straight line from
one location to another and observing the gait. The head-thrust
test is performed by instructing the patient to focus attention
on a central location while the provider turns the patient’s head
briskly to one side. Abnormal results occur when the patient is
unable to maintain visual contact with the previously designated
point as the head rotates, and as a result, the patient’s eyes must
saccade to refocus on the predetermined focal point. Etiologies
of HL that may also aect the vestibular system include genetic,
infectious, and traumatic. Usher and Pendred syndromes, which
were previously mentioned, both require further genetic testing
and referral to a medical geneticist, while trauma requires imaging to rule out labyrinthine fracture.
Additionally, all children who present with SNHL or mixed HL
should also receive at least one thorough eye exam by an ophthalmologist. Although the ophthalmology exam has been shown
to have a low diagnostic yield for ocular sequelae associated with
syndromic causes of HL, the prevalence of all eye abnormalities
is higher among infants with SNHL, and in one study 39% of
those referred were diagnosed with an eye abnormality.
ophthalmic exams can also help identify progressive syndromes
that aect vision and hearing, such as Usher syndrome, that may
present in later childhood or adulthood.
36
34,35
Serial
Pearl
All children who present with SNHL or mixed HL should be
referred for ophthalmologic examination.
Diagnostic and Etiological Testing
Table 4.1 Weber and Rinne tests and outcomes
Test Outcome Diagnostic implications
Weber Sound lateralized to midline
or both ears equally
Better ear Sensorineural loss
Poorer ear Conductive loss
Rinne Positive (air > bone) Normal or sensorineural loss
Negative (bone > air) Conductive loss
The vestibular exam commonly accompanies the general otologic exam because of the anatomic interrelation of the cochlea
and the vestibular system. In fact, some etiologies of HL are associated with a particular malfunction of the vestibular system. These
etiologies include Usher syndrome type 1 (which results in vestib-
ular areexia) and Pendred syndrome (which may be associated
with episodic vestibular dysfunction). Even with nonsyndromic
HL, vestibular issues are common, as studies have demonstrated
Normal (or sensorineural loss)
Hearing loss should be considered a clinical finding rather than
a diagnosis in itself. After medical history, physical examination,
and formal audiometric testing have been completed, the potential etiologies will commonly have been narrowed. The results of
these exams dictate the types of tests that may be required for
diagnosis. For example, a child with moderate CHL and middle
ear eusion on physical exam can forgo further testing and
be initially treated conservatively with observation and close
follow-up. However, if the CHL is persistent, speech-language
evaluation is critical to be sure that language and literacy are not
being delayed. Conversely, the newborn with bilateral profound
SNHL identified via newborn hearing screening may require labs,
genetic tests, and imaging for proper characterization as well as
both audiologic and speech-language follow-up. In general, CHL
is far more commonly diagnosed via history and physical examination alone, since the etiologies are routinely located in the
external or middle ear, whereas pathologies causing SNHL are
generally hidden. Accordingly, much of the following discussion
is particularly applicable to SNHL.
45
I Hearing Loss: Essential Information
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Pitfall
Coexisting CHL can make the evaluation and management of
SNHL more complex. Likewise, sensorineural impairment can
complicate management of CHL.
Historically, physicians have used a one-size-fits-all approach
to the laboratory diagnosis of HL, using a battery of common medical tests at once in an attempt to identify the underlying etiology.
ecent studies suggest, however, that the diagnostic yield of such
R
an approach to testing is < 2%, and testing should instead be guided
by the results of the history and physical examination.37 Tests that
can be used as suggested by the history and physical exam include
testing for congenital infections (CMV, syphilis, rubella), renal
anatomy and function, electrocardiogram, thyroid function, complete blood count, vestibular testing, ophthalmologic evaluation
and electroretinography, and temporal bone imaging (Table 4.2).
Pitfall
CMV testing in congenitally deaf infants must be done promptly
after birth in order to properly rule out postnatal CMV infection,
which does not cause HL.
recent decades, CMV has become the most common nongenetic
cause of SNHL in developed nations.38 CMV is estimated to be
the cause of congenital SNHL in approximately 10% of cases and
may be more prevalent than any single genetic etiology.39 CMV
can be insidious given that the HL can develop at any time during
childhood and the infection is very often otherwise asymptom-
atic. Thus, infants identified with congenital CMV require close
audiological follow-up regardless of the outcome of the newborn
hearing screening.
birth, it is important to initiate antiviral treatment, as studies
have shown greater hearing preservation in neonates treated with
antivirals than in those who were not.42 For infants who are not
tested in the first few weeks of life, diagnosis via polymerase chain
reaction (PCR) of the blood spot obtained during the neonatal
period (if it is available) can be done to dierentiate congenital
CMV from postnatal CMV, because the latter is not associated with
an increased risk of HL.
40,41
For those infants who are symptomatic at
37
Pitfall
Although infants with congenital CMV may appear asymptomatic, they should be closely monitored via audiology for the
development of HL.
Perhaps the most pervasive testing done in congenitally deaf
infants is screening for congenital infections that cause pediatric
HL. These infectious etiologies include cytomegalovirus (CMV),
toxoplasmosis, rubella, and syphilis. While the prevalences of
congenital rubella, toxoplasmosis, and syphilis have declined over
Table 4.2 Laboratory tests used to evaluate children with sensorineural hearing loss and their approximate diagnostic yield*
Test Finding Disease/Syndrome Approximate yield (%)
Complete blood count Abnormalities may signal leukemias
Platelet count Macrothrombocytopenia Fechtner syndrome < 1
Antinuclear antibody Elevated Lupus/other autoimmune disorders associated
Erythrocyte sedimentation
rate
Rheumatoid factor Elevated Lupus/other autoimmune disorders associated
Thyroid-stimulating hormone Hypothyroidism Pendred syndrome 2
Blood urea nitrogen Elevated Alport syndrome < 1
Creatinine Elevated Alport syndrome < 1
Urinalysis Proteinuria Alport syndrome < 1
Blood glucose Elevated Alstrom syndrome/diabetes < 1
Fluorescent treponemal
antibody—absorbed
Rapid plasma reagent Positive Syphilis < 1
Lipids Elevated Hyperlipidemia associated with hearing loss < 1
Source: Used with permission from Prosser JD, Cohen AP, Greinwald JH. Diagnostic evaluation of children with sensorineural hearing loss. Otolaryngol Clin N Am.
2015:48;975–982.
associated with hearing loss
Elevated Lupus/other autoimmune disorders associated
Positive Syphilis < 1
Pearl
Intrauterine infection with CMV is associated with HL, whereas
postnatal infection with CMV is not.
Leukemia < 1
< 1
with hearing loss
< 1
with hearing loss
< 1
with hearing loss
46
4 Medical Management of Hearing Loss in Children
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Children presenting with bilateral severe to profound HL who
have a personal history of fainting or a family history of sudden
infant death syndrome (SIDS), or sudden death at any age, along
with HL should be evaluated via electrocardiogram, which tests
the electrical conductivity of the heart. The concern is that such
individuals are at greater risk of Jervell and Lange-Nielsen syn-
drome, which aects the body’s ability to regulate key ions that
are used by cardiac myocytes to generate the regular heart rate
and rhythm. As such, these individuals are at higher risk of sudden
death; therefore, testing should be pursued promptly.
Many of the other tests that may be pursued in a patient with
pediatric HL are to help identify syndromic diagnoses, including
thyroid function tests (Pendred), kidney imaging and function
testing (BOR, Alport), vestibular testing (Usher type 1), electrocardiogram (Jervell and Lange-Nielsen), and electroretinography
(Usher). These tests are used when physical exam or history is
suggestive of such diagnoses and commonly will be used in conjunction with further genetic testing.
Over recent decades, the genetic causes of pediatric HL have been
intensely studied. Genetic etiologies must be seriously considered
in pediatric patients with HL, because it is estimated that more
than 50% of congenital HL is due to a genetic cause.
syndromes have been associated with HL, and more than 100 genes
have been implicated in genetic SNHL.
one test for all of the genes known to be associated with HL, there
are genetic panels available to clinicians that identify the most
common mutations.
discussed within the context of the physical exam and laboratory
testing, such syndromes represent approximately 30% of genetic
causes of HL, whereas 70% of genetic causes are nonsyndromic.43
For the physician, it is important to consider genetic testing or a
referral to a medical geneticist for pediatric HL patients. As the
costs of genetic panels have approached the cost of single-gene
testing, the use of these less specific tools has increased. Given the
ramifications of genetic testing in children who cannot provide
direct consent, it is important to discuss this option thoroughly
with the patient’s caregivers and preferably include a genetic
counselor consultation whenever possible. (See Chapter 3 for more
information regarding the genetics of pediatric HL.)
45,46
While various genetic diagnoses have been
37,43
Although there is no
43,44
Over 400
management depending on the suspected etiology. Advantages of
CT include its lower cost, superior resolution of bony structures,
and tolerability without sedation in pediatric patients, yet these are
counterbalanced by the child’s exposure to ionizing radiation and
poor resolution of soft tissue structures. Advantages of MRI include
its superior soft tissue resolution, including nerve and brain structures, while drawbacks include its higher cost and lower tolerance
in unsedated children. Some of these risks can be mitigated, such
as via sedation during MRI in young children or utilizing dierent
CT modalities (such as cone-beam CT instead of multislice CT) that
may involve less radiation.
which type of imaging is preferential for each etiology. To a large
degree, preferences of each institution, the radiologist, and the
otolaryngologist are used to determine which modality is used.
47,48
Additionally, controversy exists over
49
Pearl
Both CT and MRI play an important role in the diagnosis of pediatric HL, and their use depends on suspected etiology, provider,
and institution.
Uses of CT include delineating the anatomy and bony structures
of the EAC and middle ear, evaluating trauma of the temporal
bone, and identifying congenital and acquired anomalies includ-
ing cholesteatoma. It is additionally useful for de
omy in planning surgical intervention, particularly for children
with craniofacial anomalies. A recent systematic review of CT in
pediatric HL found its diagnostic yield to be approximately 30%
(Fig. 4.4).
50
fining bony anat-
Pearl
The majority of genetic HL is nonsyndromic.
Diagnostic Imaging
Imaging plays an essential role in the diagnosis of pediatric HL.
This is because the vast majority of the auditory system (the
cochlea, cochlear nerve, and brain) is beyond visualization at the
traditional otologic exam. By utilizing modern imaging modali-
ties, the physician is able to verify suspected findings or search
for possible causes of pediatric HL.
Two types of imaging are most commonly used in patients with
HL: CT and magnetic resonance imaging (MRI). Both tests can be
used either in conjunction or independently to guide diagnosis and
Fig. 4.4 Temporal bone fractures, visualized by CT. (Used with
permission from Behrbohm H, Kaschke O, Nawka T, Swift A. Ear, Nose
and Throat Diseases, 3rd ed. New York, NY: Thieme Publishers; 2010.)
47
I Hearing Loss: Essential Information
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Etiologies that are commonly identified via CT of the temporal
bone include trauma, ossicular chain disruption, cholesteatoma,
and otosclerosis. Sequelae of temporal bone trauma in children are
slightly dierent from those in adult populations, given the relative immaturity of the bony structure of the pediatric population,
and can result in CHL, usually secondary to blood in the middle ear
space, tympanic membrane perforation, or ossicle disruption.51
Treatment of such temporal bone trauma depends on the severity,
with severe cases necessitating emergent stabilization and urgent
reconstruction, while less severe cases may be closely monitored
as the trauma naturally heals. Cholesteatomas (discussed previously in relation to tympanic membrane perforation) can also
occur congenitally. Because these benign growths are confined
to the structures of the middle ear and may not be visible on
physical exam, CT has proven an eective method for diagnosis
and quantification of size and location. Otosclerosis is rare among
pediatric populations but lends itself to a radiologic diagnosis
because the hypodensity of bone, pathognomonic of this etiology,
will sometimes be readily visible on CT imaging. Once identified,
otosclerosis may be managed with a hearing aid or stapedotomy.
MRI is useful for children with suspected cochlear nerve pathology including nerve hypoplasia, tumors, or associated neurologic
findings. Except on bony anatomy, MRI oers similar or better
resolution of inner ear structures compared to CT. The diagnostic
utility of MRI is similar to that of CT, identifying etiology in 24% of
patients, compared to 18% for CT in a recent study of 270 children
with SNHL (Fig. 4.5).
34
MRI is mainly used when fine detail is needed or soft tissue is
believed to be involved with the cause of the HL. Etiologies that may
be apparent on MRI evaluation include cochlear malformations
(Michel, Mondini, Scheibe, Alexander), enlarged vestibular aque-
duct (EVA), cochlear nerve deficiency, and vestibular schwannomas.
The types of cochlear malformations vary and represent
malformation of the inner ear’s meticulous anatomy, rendering
it incapable of transducing the signal from the middle ear to the
cochlear nerve. The Michel malformation occurs when the inner
ear simply does not form. Mondini occurs when the cochlea does
not fully develop and commonly contains only 1.5 turns instead
of the expected 2.5. Scheibe malformations represent defects of
the membranous portion of the inner ear, while the bony exterior
forms normally. Lastly, Alexander malformations occur when
only a portion of the cochlear duct malforms. The treatment for
these malformations depends on the severity of their audiometric
manifestations rather than their anatomic severity. Those patients
who do not receive adequate benefit from a conventional hearing
aid may potentially benefit from CI (Fig. 4.6 and Fig. 4.7).
EVA is the most common radiographically identified cause
of congenital sensorineural hearing loss.52 It is estimated that
approximately 15% of pediatric SNHL is caused by this malformation.53 Patients with EVA can vary in the onset and severity
of HL, and even minor head trauma can induce the HL or cause
acute worsening of the HL. Although controversial, anecdotal
experience has suggested that patients with EVA may be at risk
for progression of hearing loss from mild head trauma, and as a
result, they should consider avoidance of contact sports (Fig. 4.8).
Cochlear nerve deficiency (CND), defined as either an abnormally thin or a completely absent cochlear nerve, is another
diagnosis made via imaging and can be identified via CT or MRI.
Fig. 4.5 Bilateral vestibulocochlear nerves (CN VIII), revealed on
MRI. (Used with permission from Moeller TB, Reif E. Pocket Atlas of
Sectional Anatomy: Computed Tomography and Magnetic Resonance
Imaging. Vol. 1: Head and Neck, 3rd edition. New York, NY: Thieme
Publishers; 2007.)
Fig. 4.6 Cochlear embryology. (Used with permission from Probst R,
Grevers G, Iro H. Basic Otorhinolaryngology, 1st edition. New York, NY:
Thieme Publishers; 2006.)
48
Fig. 4.7 CT showing inner ear dysplasia and dysplastic cochlea. (Used
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
with permission from Moedder U, Cohnen M, Andersen K, Engelbrecht
V, Fritz B. Direct Diagnosis in Radiology: Head and Neck, 1st ed. New
York: NY: Thieme Publishers; 2008.)
4 Medical Management of Hearing Loss in Children
surgical exploration. Treatments for perilymphatic fistula include
observation and bed rest or surgical intervention to prevent further leakage, depending on the severity.
While it is uncommon for neoplastic disease to cause HL in
children, it is important to consider vestibular schwannomas in a
pediatric patient with progressive SNHL. These benign neoplasms
are commonly located on the vestibular portion of the eighth cranial nerve, but they impinge on the function of the cochlear nerve
and must be visualized with contrast-enhanced MRI for diagnosis.
Although they are commonly associated with the genetic syn-
drome of neurofibromatosis type 2, they can occur sporadically.60
Symptoms include subtle onset of HL, tinnitus, disequilibrium,
dizziness, and sometimes facial nerve dysfunction. The treatment
options for vestibular schwannomas include observation, surgical
resection, and radiotherapy. If the cochlear nerve is preserved after
these interventions, some hearing may be restored via CI (Fig. 4.9).
61
4.3 Surgical Intervention in
Pediatric Hearing Loss
With MRI one can precisely calculate the diameter of the cochlear
nerve, while CT can also be used to measure an abnormally small
internal auditory canal.54 CND may be as prevalent as EVA: in one
recent study 18% of ears with SNHL were found to have CND.55
Treatment for CND varies depending on the degree of deficiency.
Patients with small, yet present cochlear nerves can benefit from
CI, while those with absent cochlear nerves may not. It should also
be noted that outcomes vary among patients who receive CI for
CND, and studies suggest that such patients will have less speech
understanding and environmental awareness than those with
normal cochlear nerves.
Other notable anomalies of the cochlea include perilymphatic
fistulae. These abnormal communications between the inner and
middle ear allow drainage of the perilymph, causing inner ear
malfunction.58 While most commonly associated with trauma or
congenital malformation, they have been reported to occur spontaneously.59 Symptoms vary yet commonly include uctuating
SNHL, disequilibrium, and aural fullness. Diagnosis depends on
56,57
Eective treatment of pediatric HL involves speech-language
therapy, hearing aids, bone conduction devices, CI, hearing assistive technology, pharmacologic, and surgical interventions. No
matter one’s role in the hearing healthcare team, it is important
to have a firm understanding of all interventions, their indications, and their potential benefits and risks in order to counsel
patients properly. This section will expound on the treatments
for pediatric HL discussed in the previous section, with particular emphasis on medical and surgical treatments, namely tympanotomy, stapedotomy, ossicular chain reconstruction (OCR),
osseointegrated auditory implant (OAI), and CI.
Pearl
It is essential to consider the expectations and desires of the
patient and caregivers when planning surgical intervention in
pediatric HL.
a b c
Fig. 4.8 Enlarged vestibular aqueducts (EVA). (a, b) CT scans and (c) MRI scan of bilateral EVAs (arrows). (Used with permission from Peters BR.
Case 20. Enlarged vestibular aqueduct: uctuating, mixed hearing loss. In: Madell J, Flexer C. Pediatric Audiology Casebook. New York, NY: Thieme
Publishers; 2011.)
49
I Hearing Loss: Essential Information
Madell et al., Pediatric Audiology: Diagnosis, Technology, and Management, 3rd Ed. (ISBN 978-1-62623-401-7),
copyright © 2019 Thieme Medical Publishers. All rights reserved. Usage subject to terms and conditions of license.
Fig. 4.9 MRI showing bilateral (L > R) vestibular schwannomas (arrows). (Used with permission from Holbert SO, Cevette MJ, Barrs D, Scheibler L,
Follett K. Clinical management of a patient with bilateral vestibular schwannomas. In: Valente M, Valente LM. Adult Audiology Casebook. New York,
NY: Thieme Publishers; 2015:27–31.)
4.3.1 Pharmacology
Pharmacology currently plays a specific yet important role in
the management of pediatric HL by way of antibiotic and steroid medications. Antibiotics are integral to the treatment of
infections that cause HL, including otitis externa, otitis media,
congenital infections, and bacterial meningitis. In addition to
antibiotics, corticosteroids are useful to preserve hearing in
inammatory disorders that would otherwise cause HL, such
as bacterial meningitis or idiopathic sudden SNHL. An extensive
review of corticosteroids in bacterial meningitis found that
patients with bacterial meningitis who received corticosteroids
had lower rates of any type of HL (13.8% vs 19%) and neurologic
sequelae (17.9% vs 21.6%).62 Over the past few decades, research
into novel medications that could potentially halt or reverse
deterioration of the auditory system has increased but has not
yet produced medications approved for clinical use.
Pitfall
Since middle ear infection can be the result of viral or bacterial
infection, antibiotics are not always indicated.
4.3.2 Hearing Technology
Hearing aids are essential to the treatment of pediatric HL and,
when appropriate, should be provided as early as possible to
maximize speech-language and communication development.
Air conduction hearing aids are commonly used by children who
63
have mild to severe hearing loss. Some children may be better
candidates for a bone conduction hearing device. The decision
of whether a child is best served by air conduction hearing aid
technology or a bone conduction device is based on both the etiology and the clinical presentation of the child. Bone conduction
ould be more appropriate than air conduction when the child
w
has chronic otorrhea or an atretic ear canal that cannot support
a traditional air conduction hearing aid.64 For more information
regarding hearing technology see Section III.
4.3.3 Myringotomy with Tympanostomy
Tube Placement
Myringotomy with tympanostomy tube placement is the most
common ambulatory procedure in children. In 2006 alone,
667,000 children underwent tympanostomy tube placement
in the United States.65 Indications for this procedure include
prolonged otitis media with eusion or eusion that results in
HL, recurrent or persistent acute otitis media, and antibiotic-resistant otitis media.66 Tympanostomy tube placement is a minor
procedure wherein the surgeon makes small incisions at the base
of the tympanic membrane (myringotomy) and places a tube that
allows open communication between the EAC and middle ear. One
review of the literature found that tympanostomy tube placement
in otitis media with eusion shortened the time to HL resolution
but ultimately did not provide a dierence in the level of hearing
recovery.67 Benefits also include reduced incidence of acute otitis
media in those with tympanostomy tubes.68 Complications from
this minor procedure include tympanostomy tube obstruction,
tube extrusion, persistent tympanic membrane perforation or
atrophy, tympanosclerosis, and cholesteatoma.
69,70
50
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