ENT week Flashcards
disease of which part of the ear causes conductive deafness
outer and middle
disease of which part of the ear causes sensorineural deafness?
inner ear
atresia of the pinna and/or auditory canal is also known as what and is associated with which conditions
microtia - anotia (no ear)
hemifacial microsomeia, goldenhar syndrome, Treacher-Collins syndrome
also traumatic injury, infection, neoplastic changes
what does the outer ear comprise
pinna, external auditory meatus,
what is in the middle ear
drum to oval window
what is the primary function of the middle ear
to amplify sound
this is achieved by mechanical leverage of the ossicles (matches the impedence of air and water) and the drum to oval window ratio (drum 20x bigger than oval window)
what is surfer’s ear
exostoses of the auditory cannal - bony out growths following irritation from cold winds and water
Can lead to conductive deafness and increased incidence of infection as can “plug” the ear canal, causing pain
which part of the ear drum is more prone to retraction and cholesteatoma
the pars flaccid a
which is the weakest part of the ear drum
pars flaccida
how do perforations of the ear drum cause loss of hearing
Perforations cause a loss of vibrating area and hence amplification
Larger perforations expose the round window to incident sound waves which can cancel out true sound waves and contribute further to hearing loss
which type of perforation is associated with cholesteatoma
attic perforations
antero-inferior perforations are often remnants of what
grommets
where do most marginal perforations occur
in the postero-superior quadrant
marginal perforations are prone to cholesteatoma formation by squamous ingrowth
what is myringosclerosis
chalky patches (calcification)in the eardrum it is probably the result of abnormal healing following acute otitis media, middle ear effusion or grommet insertion
what is cholesteatoma
destructive keratinsing epithelium growth
how does cholesteatoma present
painless
smelly green ear discharge
conductive hearing loss
facial nerve palsy if bad
what is otosclerosis
thickening of bone near the stapes footplate (the fissula ante finestram) which fixes the stapes causing conductive hearing loss
in which populations is otosclerosis more common
females (M:F 2:1)
Caucasians
inherited in autosomal dominant pattern with incomplete penetrance
what methods of management are available for otosclerosis
hearing aids can be useful
surgery: piston placed through stapedotomy
what is otitis media with effusion more commonly known as and who is it more common in
glue ear
in children
- boys
- winter
- cleft palate
- Down’s
- Bottle fed babies
- Children of smokers
what often causes eusachian dysfunction in children
URTIs involving the adenoids
infective rhinitis
what percentage of glue ear will resolve without treatment
90%
what percentage of glue ear will resolve within 3 months
50%
which age group would be offered grommets with adenectomy
3.5 years - 7 years
why is it so important to treat glue ear
due to the developmental delays hearing loss can cause in children
what is presbyacusis
age associated hearing loss
list some iatrogenic causes of sensorineural hearing loss
aminoglycosides loop diuretics (reversible) chemotherapeutics (cisplatin) aspirin (reversible) erythromycin surgical trauma
which compartment of the cochlea is filled with endolymph
the scala media
where the neurepithelium is situated
endolymph has a high concentration of potassium
which compartment of the cochlea is filled with perilymph
the scala vestibuli and tympani
perilymph has a low concentration of potassium
these are supportive/protective
what causes presbyacusis
deterioration of hair cells and spiral ganglion cells