Conductive Hearing Loss Flashcards
where does the eustachian tube enter the ear?
middle ear
what should be seen at tympanic membrane?
cone of light
handle of malleus
long process of incus
chorda tympani can sometimes be visible
how can you tell which ear drum youre looking at?
cone of light points forwards
handle of malleus points backwards
how can sensorineural hearing loss be further classified?
cochlear or retrocochlear (eg acoustic neuroma)
symbols in audiogram?
triangles = bone conduction circles = right air conduction crosses = left air conduction
conductive hearing loss on audiogram?
large air bone gap
carharts notch (dip in bone conduction) indicates problem with ossicles
flat tympanogram
what can cause conductive hearing loss?
abnormalities of ear canal otitis media with effusion acute otitis media perforation cholesteatoma ossicular chain abnormalities (congenital or after trauma) otosclerosis
examples of abnormalities of ear canal which can cause conductive hearing loss?
congenital atresia
stenosis
otitis externa
compacted wax
what abnormality can cause otitis media with effusion?
eustachian tube dysfunction or obstruction
in adults - rhinosinusitis, nasopharyngeal carcinoma, nasopharyngeal lymphoma
how is otitis media with effusion managed?
hearing aids or grommets
what is a tympanogram?
measures how ear drum responds to pressure in ear canal
creates a seal in ear canal and bounces signal off tympanic membrane
how the signal bounces back gives info on tympanic membrane (flat in otitis media with effusion as packed with pus/fluid)
how can tympanic membrane appear in glue ear?
changed position of cone of light membrane sucked in, tight over ossicles colour change (yellowish fluid seen behind membrane) long process of incus more visible
what is a myryngotomy?
procedure cutting a hole in tympanic membrane
fluid sucked out and pressure equalised
grommet usually inserted to prevent recurrence
how long do grommets last?
usually fall out after around 1 year
usually resolved by then and dont need another one but some do
what is acute otitis media (without effusion) associated with?
still associated with blocked eustachian tube
URTI
commonly viral or can be bacterial
how is acute otitis media managed?
antibiotics not recommended unless symptoms last >3 days as its usually viral
generally self resolves or causes perforation which heals once infection settles
what does acute otitis media look like?
skin injected and red
membrane bulging outwards (opposite to glue ear)
complications of otitis media?
mastoiditis (infection spreads through air cell system into mastoid, bone breaks down and abscess forms)
- abscess causes ear to stick out and loss of sulcus behind the ear
how can mastoiditis be managed?
make incision behind ear
what is chronic suppurative otitis media?
chronic inflammation causing perforation and cholesteatoma
what can be seen when ear drum perforated?
can cause scarring as it heals (tympanosclerosis) which shows as white area
promentary can be seen
what is the prommentary?
basal turn of cochlea
L shape in ear drum?
horizontal part = stapedius tendon
vertical part = long process of incus
what is cholesteatoma?
presence of keratin within middle ear which grows and causing destruction of surrounding bone and infection
theory of how cholesteatoma forms?
obstructed eustachian tube > reduced pressure in middle ear > retraction of tympanic membrane > pocket formation > collection of keratin in pocket > expansion, erosion and cholesteatoma established
medial complications of otitis media and cholesteatoma?
sensorineural hearing loss tinnitus vertigo facial palsy other cranial nerve palsies
superior complications of otitis media and cholesteatoma?
brain abscess
meningitis
posterior complications of otitis media and cholesteatoma?
venous sinus thrombosis
what is otosclerosis?
gradual onset conductive hearing loss with normal examination appearances
due to fixation of stapes footplate on oval window
can be familial
progresses more rapidly in pregnancy
who is otosclerosis more common in?
women
how is otosclerosis managed?
hearing aids
stapedectomy
features of otosclerosis on audiometry?
carharts notch
normal tympanogram
how can trauma damage hearing?
can knock off ossicular chain or damage nerves
crack in temporal bone can progress track down and perforate tympanic membrane
can cause a haemotympanum (blood build up behind ear drum)
