PD2 EARS

dimensions of external ear canal

2.5 cm in length

0.8 cm in diameter

cartilage vs. bone composition of external ear canal

cartilage = outer 2/3 (hair, earwax prod)

bone = inner 1/3 (no hair, no vessels)

eustachian tube

connects middle ear to nasopharynx

equalization of pressure across TM

ossicles role

responsible for amplification of sound through lever system

middle ear

air-filled space in skull

kids eustachian tube

more horizontal → higher chance of ear infections

inner ear

encased by optic capsule

contains cochlea, vestibule, semicircular canal

fx of inner ear

hearing

balance

weber test has lateralization of sound to impaired ear = ?

unilateral conductive hearing loss

if BC is = or > than AC, then?

conductive hearing loss

best grip for otoscope for kids

pencil grip

looking at tympanic membrane

pearly-gray

can see handle of malleus

cone of light (reflection from the otoscope)

conductive hearing loss is a problem with

external or middle ear

→ impaired sound to inner ear

conductive hearing loss causes

Foreign body (wax*)

Otitis media

Perforated tympanic membrane

Otosclerosis of ossicles

The only conductive hearing loss you can NOT see during otoscopic exam

Otosclerosis of ossicles

Sensori-neural hearing loss

Inner ear problem that effects transmission of nerve impulses to brain

Sensori-neural hearing loss causes

Loud noise exposure

Inner ear infections

Trauma

Acoustic neuroma

congenital/hereditary disorders

Aging

Meningitis

PE of sensorineural hearing loss

Will not find anything abnormal

weber test findings

Conductive loss: sound lateralize to impaired ear

Sensorineural loss: sound -> non-affected side

tests for UNILATERAL hearing loss

rinne test findings

Conductive hearing loss: AC = or < BC

Sensorineural hearing loss: AC > BC

tests for UNILATERAL hearing loss

how many adults have hearing loss

>1/3 if 50+ yo

>80% if over 80+

USPSTF recommends screening hearing loss at what age

>50 yo (Grade 1)

if hearing tests are abnormal, next steps?

audiogram (sensorineural)

audiogram/referral necessary (conductive w/o visible cause)

workup for unexplained, sudden sensorineural hearing loss

CBC

BMP

TSH

BDLR

MRI or CT