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)
