Disorders of External Ear

what are the 3 functional portions of the ear?

skin, sinus and brain

what divides the external ear from the middle ear and is translucent?

tympanic membrane

cartilaginous & bony "tunnel" between nasopharynx and middle ear (makes the middle ear a sinus: hole in bone that drains into the nose)

eustachian tube

the eustachian tube opens to:

equalize middle ear pressure with atmospheric pressure

components of inner ear:

semicircular canals containing end organs for vestibular function

tip of the malleus usually faces the:

anterior portion of middle ear

most normal hearing via air conduction is also referred to as:

sensorineural

what volume is normal hearing at?

0-20 dB

if you have to go a normal spoken voice on a whisper test for your patient, what may they have? what volume is this heard at?

moderate hearing loss, 40-60 dB

which nerve sends impulses from the temporal lobe to the brain?

auditory nerve

sound vibrations may be conducted by:

bone directly to the inner ear

what are the two types of hearing?

sensorineural hearing, or conductive

which hearing is done by sound being conducted into the EAC, vibrates the TM, ossicles transmit to inner ear via oval window and then the inner ear transmits to brain for interpretation?

sensorineural hearing

conductive hearing loss is:

anything external to oval window (blockage, holes, trauma to ossicles)

which type of hearing is sound being conducted directly to inner ear via mastoid bone?

conductive hearing

common cause of sensorineural hearing loss:

older age

disruption of hearing medial to the oval window causes a:

sensorineural loss

does the weber test dx hearing loss?

no, determines if hearing is the same in both ears

Conductive hearing loss:

when BC > AC

someone with sensorineural hearing loss will still have which result on a rinne test?

AC > BC

most cochlear diseases will give you:

a bilateral symmetric hearing loss (sensorineural)

which kind of hearing loss is a problem of the cochlea where hair cells cause impaired nerve impulse transmission to the brain?

sensorineural hearing loss

risk factors for sensorineural hearing loss?

presbycusis, genetics

other causes of sensorineural hearing loss:

noise exposure, head trauma, systemic diseases, ototoxicity

what are the first things that are damaged due to noise exposure that leads to high frequency hearing loss?

outer hair cells

irreversible sensorineural hearing loss even with therapeutic doss:

ototoxicity

ototoxicity may affect:

auditory and vestibular systems

most common ear drops leading to ototoxicity:

aminoglycosides, antineoplatic agents

which ear drops should you avoid with a perforated TM?

neomycin & gentamycin

if you have to give a drug that is ototoxic, what should you do?

repeat serial audiometric tests, monitor serum peak and trough levels of meds

which hearing loss is caused by external or middle ear & imparis conduction of sound to inner ear?

conductive hearing loss

MC result in conductive hearing loss?

cerumen impaction of Eustachian tube or dysfunction of URI

persistent CHL usually comes from:

chronic ear infection, trauma, otosclerosis

hereditary unilateral conductive hearing loss in young-ish adults (35), with a strong family hx:

otosclerosis

prognosis of conductive hearing loss:

often correctable with surgical therapy/medical procedure

right ear on audiogram appears:

red

left ear reading on audiogram appears:

blue

conductive hearing loss on audiogram

studies done for both air and bone conduction:

pure tone

words with two syllables with equal accent on both syllables:

spondees

which test measures clarity of hearing?

speech discrimination

which test measures spondees in a hearing test?

speech reception threshold

lesions caused by sensorineural loss ban be identified by:

audiogram, auditory brainstem-evoked responses, MRI scan

in an audiology office, which test should you order first before ordering an MRI for sensorineural hearing loss?

ABR/BAER

when are auditory brainstem-evoked responses/MRI scans indicated in evaluating SNHL?

evaluate new/sudden onset unilateral SNHL

risk factors of sudden SNHL:

> 20 years old, unknown cause (viral?)

for sudden SNHL what should you do:

Refer ASAP, big dose of prednisone, intratympanic corticosteroids

what is typically not useful in identifying sudden sensorineural hearing loss?

physical exam, not significant findings

contemporary hearing aids:

device used for hearing rehabilitation

what treatment would you use for conductive loss or unilateral profound sensorineural loss?

bone-anchored hearing aid

how does a bone-anchored hearing aid operate?

oscillating post drilled into the mastoid and directly stimulates cochlea, can be used ipsilaterally or contralaterally

severe-profound SNHL may be helped by:

cochlear implants

device that is surgically implanted into the cochlea to stimulate auditory nerve

cochlear implant

what result to you need to qualify for a cochlear implant?

below 40% on speech discrimination test

you can also have _______ that cause SNHL

autoimmune diseases

skin cancers of the auricle:

squamous cell carcinoma, basal cell carcinoma

treatment for auricular hematomas:

incision & drainage, compression bandage, abx (bactrim), ensure they have definitive treatment

Incision of auricular hematomas are effective in:

preventing cauliflower ear

cauliflower ear

necrotizing cartilage of the outer ear caused from auricular hematomas

cellulitis of the auricle must be treated _______ to prevent development of:

ASAP, perichondritis with deformity

most common causes of auricular hematomas:

blunt trauma, wrestling, MMA

treatment of auricular cellulitis, perichondritis & chondritis:

broad-spectrum abx

cerumen:

protective secretions made by lateral 1/3 of ear canal

when should you irrigate the ear:

only if you know TM is in tact

if you can't see the TM in a child:

don't irrigate

when is it not indicated to irrigate the ear?

any perforations, tympanostomy tubes

what is the most common foreign body found in the ear?

q-tip (cotton)

which part of the ear is cerumen present?

lateral 1/3

what is present in the lateral 1/3rd of the ear that is responsible for making cerebrum and cleaning it out?

sebaceous glands and hair cells

most common cause of cerumen impaction:

self-induced through attempts to clean ear

symptoms of cerumen impaction:

ear pain, hearing loss

removal of cerumen:

mechanical removal, cerumenolytic ear drops (carbamide peroxide)

tools for foreign body removal of ear:

alligator forceps, loop or hook, irrigation for soft substances only

once a foreign body is removed what should you do?

check EAC for other objects and trauma, check nose & mouth as well

follow up in 2 wks, may do abx drops

what to do if there is a living insect in ear:

kill with 70% isopropyl alcohol in EAC, suction or irrigation to remove dead insect

alternative form of treatment for insent:

1-2 drops 2% lidocane into affected EAC, insects hate this and leave fast

patient presentation of external otitis:

otalgia, may or may not have pruritis and purulent discharge

etiology of external otitis:

hx of water exposure or mechanical trauma (scratching)

otitis externa

external otits is commonly known as:

swimmers ear

Physical exam of otitis externa:

pulling on auricle and tragus may cause pain, maybe drainage, edema

most common cause of otitis externa:

psuedomonas

how to test if it is pseudomonas:

forms fluorescein blue green under wood's lamp illumination

if severe edema prevents drops getting into the EAC what can you use to allow meds to get into the ear?

ear wicks, leave in for 48 hrs

what holds the wick in if using it to treat with external otitis to hold abx drops in?

the edema from ear infection

initial treatments for external otitis

keep ear dry, gently remove purulent debris to permit entry of meds

medications for otitis externa:

Fluroquinolone otic suspension, acetasol, vinegar after swimming practice, cortisporin otic ointment

what is a complication of useing cortisporin otic ointment for treating otits externa?

has ototoxic meds (polymyxin B, neomycin)

otomycosis

fungal otits externa

if treatment of otitis externa doesn't resolve it can lead to:

otomycosis

patient presentation of fungal otitis externa:

itchy persistant "otitis externa"

may have fungal balls or black exudate

etiology of fungal otitis externa;

abx usage

treatment of otomycosis:

clean canal with acetic acid, tx with topical antifungals, keep dry

treatment of otomycosis typically takes:

a long time to resolve

what should you prescribe for difficult cases of external otitis?

fluoroquinolones (cipro), esp for cellulitis

older chronically ill patients with foul-smelling drainage, otalgia and progressive cranial nerve palsies may be an indication of:

necrotizing external otitis

key clinical signs of necrotizing external otitis:

on-going foul smelling drainage, boring deep otalgia

patient population of necrotizing external otitis:

sick, rail old people, diabetes mellitus, immunocompromised pts

necrotizing external otitis is an:

ENT emergency called malignant external otitis

most common cause of necrotizing external otitis:

pseudomonas