ENT Brief Flashcards
which part of the ear is responsible for converting sound vibration into a nervous signal?
the cochlea
which nerve transmits signals from the chochlea and the semicircular canals to the brain
vestibulocochlear nerve
which part of the ear is responsible for sensing head movement?
semicircular canals
describe weber’s test and possible results
- make fork vibrate and place it on their forehead
- ask which ear it’s loudest in or if it’s the same in both
- normal result
- same in both
- sensorineural hearing loss
- louder in the unaffected ear
- conductive hearing loss
- louder in the affected ear
- affected ear adapts to become more sensitive so when sound transmitted directly to the cochlea through vibration they should hear it louder in the affected ear
describe rinne’s test and possible results
- put vibrating tuning fork on patient’s mastoid process until they can’t hear it anymore
- then move it 1cm away from same ear
- normal result:
- they can hear it again since air conduction should be better than bone conduction
- abnormal result (AKA rinne’s negative):
- bone conduction is better than air conduction and suggests a conductive cause of hearing loss
causes of adult onset sensorineural hearing loss
- sudden sensorineural hearing loss (over less than 72hrs)
- presbycusis (age related)
- noise exposure
- meniere’s disease
- labrynthitis
- acoustic neuroma
- neurological conditions (stroke, MS, brain tumour)
- infections
- medications
name three drug classes and an example of each that can cause hearing loss
- loop diuretics
- e.g. furosemide
- aminoglycoside antibiotics
- e.g. gentamicin
- chemotherapy drugs
- e.g. cisplatin
causes of conductive hearing loss in adults
- something blocking the canal such as ear wax
- infection
- fluid in the middle ear
- eustachian tube dysfunction
- perforated tympanic membrane
- otosclerosis
- cholesteatoma
- exostoses
- tumours
in an audiogram what symbol is used for left sided air conduction
X
in an audiogram what symbol is used for left sided bone conduction
]
in an audiogram what symbol is used for right sided air conduction
O
in an audiogram what symbol is used for right sided bone conduction
[
what will the audiogram reading be in sensorineural hearing loss
both air and bone conduction readings will be more than 20 dB, plotted below the 20 dB line on the chart.
This may affect only one side, one side more than the other or both sides equally.
what will conductive hearing loss appear like on the audiogram
bone conduction readings will be normal (between 0 and 20 dB).
air conduction readings will be greater than 20 dB, plotted below the 20 dB line on the chart
what will the audiogram look like in mixed hearing loss
Both air and bone conduction readings will be more than 20 dB in patients with mixed hearing loss
However, there will be a difference of more than 15 dB between the two with bone conduction being more sensitive and therefore plotted higher
what is presbycusis
age related hearing loss
how does presbycusis present
as people get older
sensorineural
affects high pitched sounds first
gradual
symmetrical
risk factors for presbycusis
- Age
- Male gender
- Family history
- Loud noise exposure
- Diabetes
- Hypertension
- Ototoxic medications
- Smoking
what will audiometry show in presbycusis
sensorineural hearing loss pattern, with normal or near-normal hearing at lower frequencies and worsening hearing loss at higher frequencies.
what is the definition of sudden sensorineural hearing loss
hearing loss over less than 72 hours, unexplained by other causes
a loss of at least 30 decibels in three consecutive frequency on an audiogram
what should you do if a patient presents with sudden sensorineural hearing loss
otological emergency
immediate referral to the on call ENT team for assessment within 24hrs
what are the causes of sudden sensorineural hearing loss
- most cases (90%) are idiopathic
- other causes
- infection such as meningitis or mumps
- meniere’s disease
- ototoxic medication
- MS
- migraine
- stroke
- acoustic neuroma
management of idiopathic sudden sensorineural hearing loss
- steroids under the guidance of the ENT team
- these can be
- oral
- intra-tympanic (via injection)
what is eustachian tube dysfunction normally caused by
urti
hayfever
smoking


