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EAR ROUNDS. Clinical Clerks of Block 5A UP Medicine 2011 Department of Otorhinolaryngology, UP-PGH January 21, 2010. COMMON CAUSES OF HEARING LOSS AMONG NEONATES. INTRODUCTION. NEONATAL HEARING LOSS
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EAR ROUNDS Clinical Clerks of Block 5A UP Medicine 2011 Department of Otorhinolaryngology, UP-PGH January 21, 2010
INTRODUCTION NEONATAL 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 CONDUCTIVE HEARING LOSS • Anything prevents the transmission of sound from the external environment to the cochlea cerumen neoplasm cholesteatoma
Types of hearing loss SENSORINEURAL HEARING LOSS • disruptions in transmission after the cochlea • may be results of hair cell destruction or cochlear nerve damage
Types of hearing loss MIXED HEARING LOSS
Categories of hearing loss American National Standards Institute defines hearing loss: • Slight hearing loss: 16-25 dB lost • Mild hearing loss: 26-40 dB lost • Moderate hearing loss: 41-55 dB lost • Severe hearing loss: 71-90 dB lost • Profound: > 90 dB lost
EPIDEMIOLOGY • In the US, hearing loss occurs in about 10/1000 children • 1 / 1000 profound • 3-5 / 1000 mild-moderate • 10-20% 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 • 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 • Genetic • Non-Genetic • 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)
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, ototoxicmedications,(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