EAR ROUNDSClinical Clerks of Block 5A UP Medicine 2011Department of Otorhinolaryngology, UP-PGHJanuary 21, 2010

COMMON CAUSES OF HEARING LOSS

AMONG NEONATES

INTRODUCTIONNEONATAL HEARING LOSS• A significant disability which any delay in early

recognition, diagnosis and intervention will cause a significant detrimental impact on speech, language and cognitive abilities (Fakhim

2007).• Important to determine its prevalence,

frequency, usual causes and significant risk factors

Types of Hearing

Loss

Types of hearing lossCONDUCTIVE HEARING LOSS

• ANYTHING PREVENTS THE TRANSMISSION OF SOUND FROM THE EXTERNAL ENVIRONMENT TO THE COCHLEA

cerumen cholesteatomaneoplasm

Types of hearing lossSENSORINEURAL HEARING LOSS

• DISRUPTIONS IN TRANSMISSION AFTER THE COCHLEA

• MAY BE RESULTS OF HAIR CELL DESTRUCTION OR COCHLEAR NERVE DAMAGE

Types of hearing lossMIXED HEARING LOSS

Categories of Hearing

Loss

Categories of hearing lossAmerican National Standards Institute defines hearing loss:Slight hearing loss: 16-25 dB lostMild hearing loss: 26-40 dB lostModerate hearing loss: 41-55 dB lostSevere hearing loss: 71-90 dB lostProfound: > 90 dB lost

Epidemiology of Hearing

Loss

EPIDEMIOLOGY• In the US, hearing loss

occurs in about 10/1000 children1 / 1000 profound3-5 / 1000 mild-moderate10-20% acquired

EPIDEMIOLOGY• Hearing loss requiring intervention among NICU admitted patients ranges from 1 to 4%

• SNHL occurs in 9-27 per 1000 children worldwide

• Though no sex predilection is noted, hereditary causes may occur more frequently in one sex than the other

EPIDEMIOLOGY• Most hearing loss in children is congenital or acquired perinatally but may occur at any age

• Approximately 10-20% of all cases are acquired postnatally

EPIDEMIOLOGY• Prior to routine

neonatal hearing screening, hearing loss was usually diagnosed at 2.5 years, now it improved to 14 months

EPIDEMIOLOGY•Suspicion & Detection

– Parents: 2/3 of the cases

– Pediatricians: 10%– Other Healthcare providers: 15%

•The mean time from suspicion to diagnosis is about 9 months

High-Risk Criteria for HL in

Neonates & Infants

High risk criteria• The dissemination of high-risk criteria for neonates and infants in 1990 did not notably alter the mean age at diagnosis.

• About 50% of children with SNHL do not meet any of the criteria listed, and only 10% of neonates have 1 or more of the high-risk criteria that prompt an evaluation.

High risk criteria•These rates are among the reasons cited for the need for universal neonatal hearing screening.

•The goals of such screening are to identify children who are deaf or hard of hearing and to start intervention by age 6 months.

Neonates (birth to 28 d)• Family history of congenital or early SNHL• Congenital infection known to be associated

with SNHL• Craniofacial anomalies• Birth weight of more than 1500 g (<3.3 lb)• Hyperbilirubinemia over the exchange level• Exposure to ototoxic medications• Bacterial meningitis• Low APGAR scores at birth• Prolonged mechanical ventilation• Findings of a syndrome associated with SNHL

Infants (29 d to 2y)• Concern about hearing, speech, language, and/or developmental delay

• Bacterial meningitis• Neonatal risk factors associated with SNHL

• Head trauma, especially with fracture of the temporal bone

• Findings of a syndrome associated with SNHL

• Exposure to ototoxic medications• Neurodegenerative disorders• Infectious diseases associated with SNHL

Causes of Neonatal Hearing Impairments

I. GeneticII. Non-GeneticIII. Unknown

I. Genetic

• Accounts for 30-50%• May be autosomal dominant/recessive, x-

linked or sporadic• Can be syndromic or non syndromic

Syndromic

• Typically present with involvement of other organ systems

• May have specific characteristic manifestations

• Cause approximately 38.5% of hearing loss present at birth (Billings, 1999)

Syndromes associated with hearing loss

Organ or System Syndrome Inheritance Pattern Hearing Loss Obvious Physical Abnormalities

External ear DiGeorge sequelae Sporadic CHL Yes

Branchio-oto-facial syndrome AD CHL Yes

Townes-Brocks syndrome AD SNHL Yes

Miller syndrome AR CHL Yes

Bixler syndrome AR CHL Yes

Cardiac Coloboma, heart disease, atresia choanae, retarded growth, and ear anomalies (CHARGE) syndrome

AD, AR, X linked, sporadic SNHL, mixed Yes

Jervell Lange-Nielson syndrome AR SNHL  ...

Limb-oto-cardiac syndrome AR CHL Yes

Renal Alport syndrome AD, AR, X linked SNHL Yes or no

Branchio-oto-renal syndrome AD SNHL, CHL Yes

Kearns-Sayre syndrome Sporadic SNHL Yes

Epstein syndrome AD SNHL  ...

Barakat syndrome AR SNHL  ...

Mental (retardation) Noonan syndrome Sporadic SNHL Yes

Killian/Teschler-Nicola syndrome Sporadic SNHL Yes

Cockayne syndrome, type I AR SNHL Yes

Gustavson syndrome X linked SNHL Yes

Dermatologic Waardenburg syndrome AD SNHL Yes

Lentigines, ECG, ocular, pulmonary, abnormal, retardation, and deafness (LEOPARD) syndrome

AD SNHL Yes

Senter syndrome AR SNHL Yes

Black locks with albinism and deafness (BADS) syndrome

AR SNHL Yes

Davenport syndrome AR SNHL Yes

Endocrine and/or metabolic Pendred syndrome AR SNHL Yes

Johanson-Blizzard syndrome AR SNHL Yes

Refetoff syndrome AR SNHL Yes

Wolfram syndrome AR SNHL Yes or no

Kallmann syndrome AD, AR, X linked SNHL, mixed Yes or no

Facial Goldenhar syndrome AD, AR CHL, SNHL Yes

Frontometaphyseal dysplasia X linked Mixed Yes

Escher-Hirt syndrome AD CHL Yes

Levy-Hollister syndrome AD SNHL Yes

Ophthalmologic Usher syndrome AR SNHL Yes or no

Marshall syndrome AD SNHL Yes

Alström syndrome AR SNHL Yes

Harboyan syndrome AR SNHL Yes or no

Fraser syndrome AR CHL Yes

Jensen syndrome X linked SNHL  ...

Orthopedic Klippel-Feil sequelae Sporadic CHL, SNHL Yes

Stickler syndrome AD CHL, SNHL, mixed Yes

Craniometaphyseal dysplasia AD, AR CD Yes

Oto-spondylo-megaepiphyseal dysplasia (OSMED) syndrome

AR SNHL Yes

Non syndromic• has isolated problem in the auditory

system • gross physical abnormality of the

structure or covert hearing impairment• estimated to represent more than half of

the genetic cases • may account for most of the cases with no

known cause

II. Non Genetic• estimated to cause 28.6 % of hearing

impairment in children (Billings, 1999)• classified into:

– Prenatal - 5-10% of cases; classified as infectious (CMV, Herpes,etc) and non infectious (teratogens)

– Perinatal - 5-15% of cases (LBW, low APGAR, etc)– Post natal - otitis media, ototoxic medications,

(aminoglycosides), infections (meningitis, mumps).

III. Unknown Causes• Causes 20-30%; 31%(Billings, 1999)• Cases with no identifiable cause for

hearing impairment• Hypothesized to be a result of denovo

mutations or unidentified risk factors