Pedi Otology and Facial Nerve Disorders Flashcards
Discuss the embryology of the external auditory
canal and middle ear structures.
● External auditory canal: First branchial groove
● ET, middle ear, mastoid air cells: First branchial pouch
● Malleus head, incus short process, and body: First
branchial arch
● Malleus manubrium, incus long process, stapes supra-
structure: Second branchial arch
● Stapes footplate: Otic capsule
What syndromes are most commonly associated
with auricular deformities?
● BOR syndrome ● Nager syndrome ● Treacher Collins syndrome ● DiGeorge syndrome ● CHARGE association
Discuss the causes of microtia.
● Unilateral:bilateral = 4:1
● Right ear:left ear = 3:2
● Male > female
● 55 to 93% are associated with external auditory canal
atresia or stenosis.
● 50% are associated with a congenital syndrome.
Describe the Marx classification system for
microtia.
Marx classification
● Grade I: Smaller than normal auricle with mild deformity,
but all parts can be distinguished
● Grade II: Abnormally small auricle with only partial helical
structure preserved
● Grade III: Severe deformity with mostly skin-only lobular
remnant
● Grade IV: Anotia
Describe the Weerda classification system for
microtia.
Takes into account surgery required for repair.
● First-degree dysplasia: Most structures of a normal auricle
are present. Reconstruction normally does not require
the use of additional skin or cartilage.
● Second-degree dysplasia: All major structures are present
to some degree, but there is enough deficiency of tissue
that surgical correction requires the addition of cartilage
and skin.
● Third-degree dysplasia: Few or no recognizable landmarks,
although the lobule usually is present and positioned
anteriorly. Total reconstruction requires the use of skin
and large amounts of cartilage.
What are the three types of cup ear deformities?
● Type I: Upper portion of the helix cupped, hypertrophic
concha, reduced auricular height
● Type II: More severe lopping of the upper pole of the ear
● Type III: Severe cup ear deformity, malformed in all
dimensions
Types I and II are considered first-degree dysplasia, and type
III is classified as third-degree dysplasia.
Describe the traditional stages of rib cartilage
graft microtia repair.
Separated by 2 to 3 months, starting around 6 years of age
● Stage I: Auricular reconstruction (creation of a cartilagi-
nous framework with autogenous rib cartilage)
● Stage II: Lobule transposition
● Stage III: Atresia repair
● Stage IV: Construction of tragus
● Stage V: Auricular elevation
What complications have been associated with
microtia repair?
● Pulmonary complications from rib harvest: atelectasis,
pneumothorax, pneumomediastinum, pneumonia
● Skin necrosis overlying the cartilage framework
● Chondritis
● Reabsorption
● Malposition of auricular implant
● Tissue breakdown of skin graft or of posterior aspect of
ear
● Keloiding of donor incision site or skin-graft areas
What are common otoplasty techniques?
Most common: ● Mustardé technique ● Furnas technique Less common: ● Farrior technique ● Converse technique ● Pitanguay technique
What complication of otoplasty can be caused by
too much flexion of the antihelix at a level equal
to the midportion of the ear and inadequate
flexion at the superior and inferior poles?
Telephone ear deformity. Can be prevented by repeatedly
checking the tension on all sutures during surgery
Describe the Weerda classification for external auditory canal (EAC) malformations.
Weerda Classification for EAC stenosis
● Type A: Marked narrowing of the EAC with an intact skin
layer
● Type B: Partial development of the EAC with a medial
atretic plate
● Type C: Complete bony EAC atresia
What are the minor and major malformations in
congenital aural atresia?
De La Cruz classification system Minor malformations: ● Normal mastoid pneumatization ● Normal oval window footplate ● Favorable facial nerve–footplate relationship ● Normal inner ear Major malformations: ● Poor mastoid pneumatization ● Abnormality or absence of oval window/footplate ● Abnormal course of the facial nerve ● Abnormalities of the inner ear
What is the grading system used to predict
prognosis for hearing improvement after repair
of aural atresia?
Jahrsdoerfer grading system
What is involved in the preoperative planning for
repair of congenital aural atresia?
Audiometric evidence of cochlear function: Ideally, auditory
brainstem response (ABR) testing should be performed
within first few days of life in patients with bilateral atresia,
preferably with unilateral atresia as well.
Radiographic three-dimensional evaluation of the temporal
bone can be deferred until age 5 or 6 years.
You are reviewing the temporal bone CT scan in
a 6-year-old child with bilateral aural atresia. The
scan demonstrates a gray mass in the middle ear
cleft on the left with associated bony erosion.
What is the most likely diagnosis?
Congenital cholesteatoma (present in 15% of cases of congenital atresia)
What are the critical elements to review on a
temporal bone CT scan that will predict hearing
prognosis in congenital aural atresia repair?
● Status of the inner ear
● Extent of temporal bone pneumatization
● Course of the facial nerve
● Presence of the oval window and stapes footplate
What are the two basic approaches for repair of
congenital aural atresia?
● Anterior approach: Drilling area is defined by the
temporomandibular joint (TMJ) anteriorly, the middle
cranial fossa dura superiorly, and the mastoid air cells
posteriorly.
● Mastoid approach: Sinodural angle is first identified and
followed to the antrum. The facial recess is opened and
the incudostapedial joint separated. The atretic bone is
then removed.
Which congenital syndrome has a wide range of
clinical manifestations with the typical presentation
involving epibulbar dermoids or lipodermoids, mi-
crotia, mandibular hypoplasia, coloboma, hemifacial
microsomia and vertebral anomalies?
Goldenhar syndrome, also known as oculoauriculovertebral
dysplasia
What external ear anomalies are associated with
Goldenhar syndrome?
● Preauricular appendages and fistulae
● Anomalies of the auricle
● Atresia of the external auditory canal
● Microtia or anotia
What are the TORCH organisms?
● Toxoplasmosis
● Other infections: Syphilis, Coxsackievirus, varicella-zoster virus, HIV, and parvovirus B19, syphilis ● Rubella ● CMV (CMV, the most common) ● Herpes
Discuss the type of hearing loss associated with
congenital CMV infections.
Congenital CMV infections can cause SNHL in as many as
50% of children with symptomatic infections and as many as
12% of infants with asymptomatic infections. As many as
50% of cases of SNHL due to congenital CMV may have a
late onset during preschool or early school years.
What inner ear structures are affected by CMV
infection?
The exact pathophysiology of CMV-induced SNHL is not
well understood: however, infants who have died of
cytomegalic inclusion disease have temporal bones with
characteristic cytomegalic inclusion bodies in the superficial
cells of the stria vascularis, Reissner membrane, limbus
spiralis, saccule, utricle, and semicircular canals.
What is the difference between symptomatic con-
genital rubella infections and asymptomatic congen-
ital rubella infection?
● Symptomatic infection (rubella syndrome) occurs in the
first trimester of pregnancy producing hearing loss in
approximately 50% of patients. Other findings include
cardiac malformations, visual loss (e.g., cataracts, glau-
coma, retinitis, microphthalmia), osteitis, motor deficits,
thrombocytopenic purpura, hepatosplenomegaly, icter-
us, anemia, low birth weight, and cerebral damage and
mental retardation.
● Asymptomatic infection results from infection during the
second or third trimesters of pregnancy and is silent at
birth. It is associated with hearing loss in 10 to 20% of
patients. Hearing loss is most commonly seen audio-
metrically as a cookie-bite pattern.
What are the inner ear anomalies most commonly
seen in congenital rubella infection?
● Cochleosaccular degeneration (Scheibe dysplasia)
● Strial atrophy
How are early and late congenital syphilis infections
defined, and how do they influence hearing loss?
● Early infection: Initial symptoms present from birth to 2
years of age. SNHL is bilateral, flat, and usually without
vertigo.
● Late infection: Initial symptoms can be seen anytime after
2 years of age and into the sixth decade of life. SNHL can
be sudden, asymmetric, fluctuating, and progressive,
accompanied often by episodic tinnitus and vertigo.
What are the major features of congenital syphilis
infection?
● Sensorineural hearing loss
● Interstitial keratitis
● Hutchinson teeth (notched incisors)
● Mulberry molars
● Clutton joints (bilateral painless knee effusions)
● Nasal septal perforation and saddle deformity
● Frontal bossing
● Skeletal findings: Osteochondritis and periostitis of long
bones leading to “saber shin” deformity
What are the clinical findings in congenital toxoplas-
mosis infection?
At birth, 90% of infants with congenital toxoplasmosis have
no signs or symptoms. A subclinically infected infant may
later develop progressive lesions, most commonly chorio-
retinitis. Other findings include progressive CNS involve-
ment with decreased intellectual function, SNHL commonly
associated with calcified scars in the stria vascularis, and
precocious puberty.
When do the most common congenital cochlear
malformations occur during development?
● Complete labyrinthine aplasia (Michel aplasia): Arrest at
week 3 of gestation
● Common cavity: Arrest at week 4 or 5 of gestation
● Cochlear hypoplasia: Arrest at week 5 of gestation
● Cochlear aplasia: Arrest at week 6 of gestation
● Incomplete partition (Mondini malformation, most com-
mon): Arrest at week 7 of gestation
What congenital anomaly results in the complete
absence of differentiated inner ear structures and
may be associated with stapes aplasia or malforma-
tion, anomalous facial nerve course, and vestibulo-
cochlear nerve aplasia?
Michel aplasia
What is the pathophysiology of Michel aplasia?
Developmental arrest of the otic placode before gestational
week 3. It has also been associated with thalidomide
exposure.
What congenital ear anomaly results from develop-
mental arrest of cochlear formation at week 7
of gestation, causing a failure in cochlear
partitioning, an absent interscalar septum, a
modiolus that is poorly formed or deficient, and a
cochlea with only 1 to 1.5 turns?
Mondini malformation
Mondini malformation is commonly seen in what
congenital syndrome?
Pendred syndrome
What additional inner ear anomalies are commonly
seen in the evaluation of a child with Mondini
malformation?
● Enlarged vestibular aqueduct
● Semicircular canal deformities
● Communication with subarachnoid space (increased risk
for meningitis)
Patients with a Mondini malformation are at risk of
what complication during cochlear implantation?
Perilymphatic (CSF) gusher. This complication is not a
contraindication to implantation, as good hearing out-
comes have been demonstrated despite significant peri-
lymphatic gusher noted intraoperatively, but patients
should be counseled appropriately regarding the increased
risk (although low) of a dead ear or bacterial meningitis.
Arrested development of the pars inferior of the
otocyst causes dysplasia of the cochlea and saccule,
but it does not impact the semicircular canals and
utricle, which results in what congenital ear dysmor-
phology?
Scheibe dysplasia (cochleosaccular dysplasia)
What congenital anomaly results from aplasia of
the cochlear duct and subsequent dysfunction of
the organ of Corti, particularly the basal turn of
the cochlea and adjacent ganglion cells, and how
does it impact hearing?
Alexander aplasia. High-frequency hearing loss is most
prominent, whereas low frequency is relatively preserved.
What is enlarged vestibular aqueduct syndrome?
It is a combination of SNHL, inner ear abnormalities (wide
range), and enlarged vestibular aqueduct that can be
associated with Pendred syndrome, distal renal tubular
acidosis, Waardenburg syndrome, X-linked congenital
mixed deafness, BOR syndrome, otofaciocervical deafness,
and Noonan syndrome.
What is the radiographic definition of an enlarged
vestibular aqueduct?
On CT, the vestibular aqueduct is diagnosed as enlarged
when the aqueduct is greater than 1.5 mm wide at the
midpoint between the common crus and its external
aperture. This is roughly the diameter of the posterior
semicircular canal. However, this is controversial, and
diagnostic thresholds have been reported from 0.9 to 2 mm
at the midpoint and 1.9 to 4 mm at the operculum.
What percentage of congenital SNHL is genetic?
Approximately 60% of cases of congenital SNHL can be
linked to a genetic cause, with roughly 30% of these
considered syndromic (most commonly Pendred) and the
remaining 70% nonsyndromic.
Discuss the genetics of nonsyndromic hearing loss.
● 80% of cases are autosomal recessive.
● 20% of cases are autosomal dominant.
● < 2% of cases are due to X-linked and mitochondrial
mutations.
What disorder is characterized by hearing loss,
vestibular dysfunction, and visual loss resulting
from retinitis pigmentosa?
Usher syndrome. The subtypes are distinguished by the
severity and progression of hearing loss and the presence or
absence of vestibular dysfunction, with visual loss due to
retinitis pigmentosa being common to all three subtypes.
What are the clinical manifestations of each type
of Usher syndrome subtype?
● Type 1: Profound congenital deafness and absent
vestibular function (vestibular ataxia), onset of retinitis
pigmentosa before puberty (around the age of 10 years).
Autosomal recessive
● Type 2: Hearing loss is moderate to severe at birth.
Normal vestibular function. Onset of retinitis pigmentosa
is in late teens. Autosomal recessive; most common
● Type 3: Progressive hearing loss. Variable vestibular
function. Retinitis pigmentosa begins at puberty. Auto-
somal recessive
● Type 4: Clinically similar to type 2 but with X-linked
recessive inheritance
What are the pathologic temporal bone findings
in patients with Usher syndrome?
Marked atrophy of the organ of Corti in the basal turn
associated with spiral ganglion degeneration. These coch-
lear changes are similar to Scheibe inner ear dysplasia.
SNHL, which may be profound at birth or
progressive, and abnormal iodine metabolism typi-
cally resulting in a euthyroid goiter are the classic
manifestations of which congenital disorder?
Pendred syndrome
What inner ear abnormalities are found in patients
with Pendred syndrome?
● Modiolar deficiency and vestibular enlargement (100%)
● Absence of the interscalar septum between the upper
and middle cochlear turns (75%)
● Enlargement of the vestibular aqueduct (80%)
What is the most likely diagnosis for a child with
congenital bilateral severe to profound SNHL, pro-
longed Q-T interval, and a history of syncopal events?
Jervell and Lange-Nielson syndrome (autosomal recessive)
What is the pathophysiology of the hearing loss in
patients with Jervell and Lange-Nielson syndrome?
Two genes, KVLQT1 and KCNE1, have been linked to Jervell
and Lange-Nielsen syndrome. These genes encode for
subunits of a potassium channel expressed in the heart and
inner ear. Hearing impairment is due to changes in endolymph
homeostasis caused by malfunction of this channel. Patients
may suffer syncopal events, seizures, and life-threatening
cardiac arrhythmias resulting in sudden death.
What are the criteria required for diagnosis of
Waardenburg syndrome type 1?
Criteria published by the Waardenburg Consortium in 1992:
Patient must have two major criteria or one major plus two
minor criteria for diagnosis of Waardenburg syndrome type I:
Major Criteria:
● Congenital SNHL (up to 60%)
● Iris pigmentary abnormality (two eyes of different colors,
heterochromia iridis; one eye of different colors; segmental
heterochromia; brilliant blue/sapphire iris)
● Hair hypopigmentation (white forelock or white body hair)
● Distopia canthorum (lateral displacement of the inner
canthi, decreased visible sclera medially)
● First-degree relative previously diagnosed with Waar-
denburg syndrome
Minor Criteria:
● Congenital leukodermia (several areas of hypopigmented
skin)
● Synophrys or medial eyebrow flare
● Broad, high, nasal root
● Hypoplastic alae nasi
● Premature graying of hair (white scalp hair before age 30,
generally occurring midline instead of at the temples)
Rare: Hirschsprung disease, Sprengel anomaly, spina bifida,
cleft lip and/or palate, limb defects, congenital heart
anomalies, abnormal vestibular function, broad square jaw,
low anterior hairline.
How are Waardenburg syndrome types 2, 3, and
4 classified?
All are based on type 1 requiring two major or one major
and two minor criteria
● Type 2: Type 1 without the dystopia canthorum
● Type 3 (or Klein-Waardenburg syndrome): Type 1 with
hypoplasia or contracture of the upper limbs
● Type 4 (or Waardenburg-Shah syndrome): autosomal
recessive or dominant; type 1 with Hirschsprung disease
or other neurologic disorders
