This document summarizes sensorineural hearing loss (SNHL) in children. It discusses the etiology, epidemiology, and causes of SNHL. For congenital SNHL, it describes genetic causes like autosomal dominant and recessive mutations, as well as non-genetic causes like viral infections and trauma during birth. Acquired SNHL is commonly caused by bacterial meningitis in young children. Ototoxic drugs are another significant cause of SNHL and the document lists several classes of drugs that can damage the inner ear. Imaging plays an important role in evaluating childhood SNHL to identify anomalies and guide treatment.

1. ETIOLOGY OF
SENSORINEURAL HEARING LOSS (SNHL) IN
CHILDEREN
BY: BIJAY BHATTARAI
ROLL: LX111O1410
GRADE: IV

2. Sensorineural hearing loss (SNHL) :
Sensorineural hearing loss (SNHL) occurs when there is damage to the inner
ear (cochlea), or to the nerve pathways from the inner ear to the brain. Most of the
time, SNHL cannot be medically or surgically corrected. This is the most common
type of permanent hearing loss. There are characteristic features of SNHL/ which
differentiate it from conductive hearing loss .
Sensorineural hearing loss can be:
mild
moderate &
severe, including total deafness.

3. EPIDEMIOLOGY
SNHL is the most common sensory deficit in more
developed societies. In the USA, congenital SNHL
occurs about three times more frequently than Down’s
syndrome, six times more frequently than spina bifida,
and over 50 times more frequently than
phenylketonuria. An estimated 4000 infants are born
each year with severe to profound bilateral hearing
Loss, and another 8000 are born with unilateral or
mild to moderate bilateral SNHL

4. CAUSES OF SNHL
CONGENITAL
• GENETIC
• NON GENETIC
ACUIRED
•Idiopathic SSNHL Perinatal asphyxia and kernicterus
•Labyrinthitis Presbyacusis
•Ototoxicity Suppurative otitis media
•Cochlear otosclerosis Endolymphatic hydrops
•Trauma to inner ear Acoustic neuroma

5. CONGENITAL SNHL
• Genetic
Syndromic
Non Syndromic: -More common than Syndromic
Autosomal dominant SNHL
X-linked SNHL
Autosomal recessive SNHL-more common

6. • Non genetic (Embryopathies):
•Aplasia - Michel, Mondini, Scheibe, Alexander
•Viral- mumps, measles,
•Ototoxocity
•Trauma to labyrinth & cranial nerve VIII in fractures of temporal
bone & ear surgery
Congenital SNHL

7. Genetic SNHL in infants and young children
•The relative contribution of genetics to the total number of infants and young
children with SNHL is unknown.
•Inherited hearing loss diagnosed among children of these age-groups is
congenital hearing loss that was present but missed during the neonatal period.
• Negligible or mild congenital hearing loss that was undetectable by available
screening methods but has become more serious and thus detectable, or late-
onset SNHL.
• In children with late-onset and progressive hearing loss, dilatation of the
vestibular aqueduct must be considered.

8. Acquired SNHL in infants and children prevalence.
It is most commonly caused by bacterial meningitis. Altogether, bacterial
meningitis accounts for about 6% of all cases of SNHL in children. The prevalence is
about 7/100,000 with a heavy age bias for younger children. 75% of affected
children are younger than 2 years, 15% are aged 2–5 years, and 10% are older than
5 years. 62 Postmeningitic SNHL can be unilateral or bilateral.

9. OTOTOXICITY
Definition:
Tendency of certain therapeutic agents to cause functional
impairment of inner ear as a side effect of pharmacotherapy
Route of administration:
Topical- creams, ointments, drops, sprays, inhalation, irrigation
Systemic- IM/ IV

10. a) Cytomegalovirus
b) Lymphocytic choriomeningitis virus
c) Rubella virus
d) Toxoplasma gondii
e) Treponema pallidum
f) Acquired infections
g) Borrelia burgdorferi
h) Epstein-Barr virus
i) Haemophilus influenzae
j) Lassa virus
k) Measles virus
l) Mumps virus
m) Neisseria meningitidis
n) Non-polio enteroviruses
o) Plasmodium falciparum
p) Streptococcus pneumoniae
q) Varicella zoster virus
INFECTIOUS PATHOGENS IMPLICATED IN SNHL IN CHILDREN
ARE VIZ;

11. DRUG / CHEMICALS
1. Aminoglycosides high risk permanent
2. Cytotoxic agents - Cisplatin high risk permanent
3. Industrial chemicals-Toluene, benzene high risk Permanent
4. Polypeptide antibiotics - Vancomycin low risk permanent
5. Macrolides low risk temporary
6. Loop diuretics- low risk temporary
7. Salicylates low risk temporary
8. Quinine derivatives unknown Temporary
9. Others-
a. Anticonvulsants c. Barbiturates,
b. Beta-blockers, d. Muscle relaxants

12. • MECHANISM OF AMINOGLYCOSIDE : Affect on sensory neuro-
epithelium of the inner ear especially outer hair cells of the
organ of Corti and type I hair cells of Crista ampulli

13. Causes of hearing loss in the paediatric population are numerous and varied, often making
evaluation and management of the condition quite challenging for otolaryngologists.
Imaging plays a central role in the work-up of childhood SNHL because it depicts
anomalies in the structures of the inner ear, frequently provides clues as to the aetiology of
the hearing loss, and may detect associated co morbid conditions. Although CT and MR
imaging are both viable imaging choices, we prefer MR imaging due to its ability to directly
assess not only the inner ear but also the cranial nerves and brain. In cases of congenital
hearing impairment, inner ear malformations and CND are fairly common, and
identification of these anomalies is critical when surgical intervention is being considered
because they may complicate or even preclude cochlear implantation in a child with SNHL.
Conclusions

14. THANK YOU