oto pediatric hearing loss

Question 1

Which intrauterine infections are associated with

the development of congenital hearing loss?

Answer 1

T Toxoplasmosis
O Other, including syphilis, varicella, and parvovirus B19
R Rubella
C Cytomegalovirus
H Herpes simplex virus

Question 2

What factors place a pediatric patient at particularly high risk for early SNHL?

Answer 2

● History of intrauterine infection
● Family history of congenital hearing loss
● Low birth weight (< 1,500 g)
● Hyperbilirubinemia
● Prolonged neonatal intensive care unit stay or prolonged
mechanical ventilation
● Concurrent craniofacial anomalies
● Exposure to ototoxic medications
● < 5 Apgar score at 1 minute, < 7 Apgar score at 5 minutes
● Bacterial meningitis

Question 3

What percentage of congenital hearing loss is

genetic?

Answer 3

Approximately 50%

Question 4

What percentage of patients with genetic hearing

loss will have associated syndromes?

Answer 4

About 70% of genetic hearing loss is nonsyndromic, and

30% is syndromic.

Question 5

What percentage of genetic hearing loss is

inherited in an autosomal dominant pattern?

Answer 5

80% autosomal recessive, 20% autosomal dominant

Question 6

What is the most common form of autosomal

dominant hearing loss?

Answer 6

Waardenburg syndrome

Question 7

Describe the four subtypes of Waardenburg

syndrome.

Answer 7

● WS1: Autosomal dominant, dystopia canthorum, SNHL,
iris pigmentary disorder, hair hypopigmentation
● WS2: Autosomal dominant, no dystopia canthorum,
SNHL, iris pigmentary disorder, hair hypopigmentation
● WS3: Autosomal dominant, dystopia canthorum, upper
limb abnormalities, iris pigmentation disorder, hair
hypopigmentation
● WS4: Autosomal recessive, no dystopia canthorum,
Hirschprung disease, SNHL, iris pigmentary disorder, hair
hypopigmentation

Question 8

What are the three most common causes of

autosomal recessive syndromic SNHL?

Answer 8

Usher, Pendred, Jervell and Lange-Nielsen

Question 9

Describe the three subtypes of Usher syndrome.

Answer 9

● Type 1: Bilateral profound deafness and vestibulopathy at
birth; “night blindness,” from retinitis pigmentosa, before
teens (most severe form)
● Type 2: Moderate to severe hearing loss at birth,
worsening vision in young adulthood, and normal
vestibular function
● Type 3: Normal hearing at birth with progressive hearing loss and retinopathy by teens, variable vestibular involvement (mild form)

Question 10

What is the most common cause of deaf-blindness

in the United States?

Answer 10

Usher syndrome

Question 11

Alport syndrome involves faulty synthesis of what

protein(s)?

Answer 11

Type IV collagen

Question 12

Describe the clinical manifestations of Norrie disease.

Answer 12

X-linked recessive syndrome that results in early rapidly progressive blindness. Progressive SNHL occurs in approximately a third of patients and usually ensues in the second to third decades of life.

Question 13

Describe the classic head and neck manifestations

of Pendred syndrome.

Answer 13

SNHL (often associated with enlarged vestibular aqueducts

and mondini malformations) and euthyroid goiter

Question 14

Describe the thyroid pathology typically seen in

Pendred syndrome.

Answer 14

Patients often develop a multinodular goiter in the second
decade of life but are usually euthyroid and rarely require
intervention.

Question 15

What specific precaution should patients diag-

nosed with enlarged vestibular aqueduct syndrome take to prevent further hearing loss?

Answer 15

Stepwise progression of hearing loss can be seen after
minor head trauma. Participation in contact sports or
activities associated with “minor head trauma” should
generally be avoided.

Question 16

Describe the typical presentation of enlarged

vestibular aqueduct syndrome.

Answer 16

SNHL generally begins in childhood and often progresses in a stepwise manner. Vestibular symptoms and mixed hearing loss may also develop.

Question 17

What gene mutation is responsible for approximately 50% of all cases of genetic hearing loss?

Answer 17

GJB2 encodes connexin 26, located on chromosome 13,

autosomal recessive inheritance pattern

Question 18

What does the GJB2 gene code for?

Answer 18

Gap junction β-2, responsible for potassium ion exchange of the inner ear

Question 19

Describe the clinical manifestations of Jervell and

Lange-Nielsen syndrome.

Answer 19

● An autosomal recessive syndrome characterized by
congenital profound bilateral SNHL and arrhythmia
● Patients may have syncopal episodes provoked by stress
or exercise.
● Sudden cardiac death from arrhythmia may occur if
untreated.
● Caused by a defect in potassium channels within the stria
vascularis

Question 20

Descrie the electrocardiographic findings in Jervell

and Lange-Nielsen syndrome.

Answer 20

Long QTc (> 500 ms) with potential for arrhythmias

Question 21

Describe the constellation of findings seen in

MELAS syndrome.

Answer 21

ME Mitochondrial encephalopathy
LA Lactic acidosis
S Stroke
Manifestations are variable and include hearing loss, limb
weakness, partial paralysis, vision loss and seizures.

Question 22

Describe the clinical features of Michel aplasia.

Answer 22

Michel aplasia is characterized by complete failure of inner

ear development resulting in congenital anacusis.

Question 23

Describe the radiographic findings with Mondini

malformations.

Answer 23

Mondini malformation accounts for more than 50% of
cochlear malformations. The characteristic findings include
an incomplete or absent partition and less than 2.5 turns.

Question 24

Describe the imaging findings of a common cavity

malformation.

Answer 24

The cochlea and vestibule are joined as a single large
confluent space. These patients typically have severe to
profound SNHL.

Question 25

What inner ear abnormalities are seen in Scheibe

dysplasia?

Answer 25

Scheibe dysplasia (also called cochlearsaccular dysplasia or
pars inferior dysplasia) includes a poorly developed organ of
Corti and sacuule, whereas the bony labyrinth, semicircular
canals, and utricle are preserved.

Question 26

What is the most common form of membranous

labyrinth dysplasia?

Answer 26

Scheibe dysplasia

Question 27

What frequencies are most commonly affected by

Alexander dysplasia?

Answer 27

High frequencies resulting from malformation of the

cochlear duct and basal turn of the cochlea