Chapter 52 - Pediatric Hearing Loss Flashcards
Most common environmental, non-genetic cause of congenital HL in developed countries
CMV
Genetic mutation to test for in patients with HL and enlarged vestibular aqueduct….which syndrome is this associated with?
SLC26A4
Pendred
Alport Syndrome: two main manifestations, inheritance
glomerulonephritis
progressive SNHL
85% X-L
15% AR
Child has congenital severe to profound HL presumed AR non-syndromic, and GJB2/6 testing NL…which syndrome should be considered?
Usher
Incidence of congenital hearing loss
Most common birth defect in developed countries
Congenital 2-4:1000
Prevalence of childhood HL (congenital/progressive/acquired)
1:50
All infants should have hearing screen before they are how old?
1 mo
43 states require newborn screening
For infants who do not pass newborn screening, what’s the next step?
F/u medical and audiological eval prior to 3mo old
Two methods of newborn hearing screening
OAE
AABR
How well do HL children do with language skills
If receive treatment at or before 6mo of age, have language skills comparable to peers regardless of degree of hearing loss
Impact of delayed Dx of HL on children
speech
academic
career
psychosocial well-being
Most critical period for children to need to hear
0-3yr
develop speech, auditory pathways, emotional bonds
If profound SNHL, cannot get auditory feedback –> cannot acquire motor speech skills
Hearing developmental milestones
<3mo: startled by loud, calmed by familiar
6mo: localize sounds
9mo: respond to name, mimic sounds
12mo: first meaningful words
18mo: react from any direction, follow commands to perform simple tasks
24mo: 20+ words (if monolingual)
RF for early childhood HL
FHx permanent childhood HL, LBW (<1500g), CF abnl, TORCHeS, maternal DM/EtOH/drug, hyperbilirubin needing exchange transfusion, Apgar <5 1min, <7 5min, postnatal infections assoc w/ HL, syndromes, neurodegen/sensorimotor neuropathy, caregiver concerns regarding hearing, head trauma, recurrent/persistent effusion lasting >3mo
Neonatal exposures associated with childhood HL
ototoxic
mechanical vent 5d+
ECMO
Causes of congenital hearing loss: inherited vs acquired
50% inherited
30% acquired/environmental
20% idiopathic
List 6 most common syndromes causing SNHL
Usher Pendred Jervell Langee-Nielsen Waardenburg Branchio-oto-renal Stickler
Usher syndrome
AR, resp for 10% congenital deafness
Most common type of AR syndromic HL, variable severity
Progressive blindness, vestibular dysfunction
MYO7A, USH2A, CDH23
Pendred syndrome
AR, resp for 5-10% AR HL
Multinodular euthymic goiter, inner ear (Mondini/enlarged aqueduct), abnormal perchlorate testing
SLC26A4
Jervell and Lange-Nielsen
3rd most common cause AR syndromic
1% of cases of recessive HL
severe bilateral HL, prolonged QT
KCNQ1, KCNE1
Waardenburg
Most common cause AD, accounts for 2% of all congenital HL
telecanthus, white forelock, hyperplastic high nasal root, hyperplastic medial eyebrows, heterochromia irides
PAX3, MITF
Branchio-oto-renal syndrome
AD
branchial fistula, renal abnormal, abnormal inner, middle, external ears including preauricular pits
EYA1, SIX1, SIX5
Stickler syndrome
AD
Cleft palate, osteoarthritis, myopia, progressive SNHL
3 types based on genes: COL2A1, COL11A1, COL11A2
Are most inherited causes of hearing loss due to syndromes or nonsyndromic?
Nonsyndromic
Single gene mendelian inheritance (>100 genes SNHL mapped, half are identified)
Percentage of nonsyndromic that are AD vs AR
80% AR
15% AD
Remainder X-linked, mitochondrial
Two most common genetic mutations causing HL
GJB2 - connexin-26 gap jxn, 30-50% of all congenital profound HL
SLC26A4- second most common cause genetic SNHL, often associated with Pendred syndrome, enlarged vestibular aqueduct
Mondini dysplasia
1.5 turns in bony cochlea (only basal turn)
early or adult presentation, variable severity HL
AD
Siebenmann Bing
complete membranous labyrinthine dysplasia
Very rare
associated with Jervell Lange Nielsen, Usher
Schiebe dysplasia
cochleosaccular
Often noted in AR congenital HL
Alexander dysplasia
cochlear basal turn
Related to familial HF SNHL
When can someone be diagnosed with membranous dysplasia
post-mortem histopathological exam
Enlarged vestibular aqueduct
1.5mm +
SNHL or mixed, may be at birth, or progressive through childhood or fluctuating
Sudden hearing loss spontaneously or with mild head trauma
Avoid contact sports
Most common ossicular abnormality, and its cause
Malleus head fixation
due to incomplete pneumatization of epitympanic space
Hearing loss severity with congenital absence of incus long process
maximal CHL (60 dB)
Type of hearing loss associated with congenital stapes fixation
stable CHL
Two common causes of acquired pediatric HL
MEE (inhibit vibration TM)
cholesteatoma, can erode ossicles or otic capsule
Prevalence of congenital CMV, and percentage of those who will develop HL
- 58%
12. 8%
How Sx vs ASx CMV infection affects HL type
Sx- bilateral
ASx- unilateral
Percentage of children with bacterial meningitis who get HL
10%, due to inflammation –> cochlear ossification
Causes of childhood bacterial meningitis (3)
S Pneumo
GBS
Neisseria
Less common H Flu b
Detection and management of HL due to bacterial meningitis
frequent hearing eval, CT T bone
Urgent cochlear implant if ossification found to preserve some membranous cochlear architecture
Image recommended to detect enlarged vestibular aqueduct
CT T Bone
Study to obtain if profound congenital deafness and absent vestibular fxn
ECG (long WT w/ Jervell-Nielsen-Lange)
Study to evaluate for Alport
Urinalysis
Study to obtain if HL associated with cleft palate
ophthalmology (Stickler Syndrome)
Medications causing ototoxicity used with pediatric patients
aminoglycosides, erythromycin, cisplatin, furosemide
Diagnosis when robust OAEs but absent or markedly dysmorphic AABR response, plus varying degree of HL
Auditory Neuropathy Spectrum Disorder
ANSD
Why genetic testing may be helpful with HL
may predict severity or other problems
chances of another child having it
provides info about whole family, so whole family must be addressed….counseling!
Which hearing aid is most often used in children as it is adaptable to growing ear canal?
Behind the ear
