ENT Flashcards
(215 cards)
Name the types of hearing loss
conductive
sensorineural
Describe conductive hearing loss
problem with sound travelling from the environment to the inner ear. The sensory system may be working correctly, but the sound is not reaching it.
Describe sensorineural hearing loss
problem with the sensory system or vestibulocochlear nerve in the inner ear
Name 3 parts of the ear
outer ear
middle ear
inner ear
name the structures of the ear
- The pinna is the external portion of the ear
- The external auditory canal is the tube into the ear
- The tympanic membrane is the eardrum
- The Eustachian tube connects the middle ear with the throat to equalise pressure
- The malleus, incus and stapes are the small bones in the middle ear that connect the tympanic membrane to the structures of the inner ear
- The semicircular canals sense head movement (the vestibular system)
- The cochlea converts the sound vibration into a nervous signal
- The vestibulocochlear nerve transmits nerve signals from the semicircular canals and cochlea to the brain
Associated sx with hearing loss
- tinnitus
- vertigo
- pain
- discharge
- neurological sx
Causes of sensorineural hearing loss
- sudden sensorineural hearing loss
- presbycusis (age related)
- noise exposure
- meniere’s disease
- labyrinthitis
- acoustic neuroma
- neurological conditions (stroke, MS, brain tumours)
- infections (meningitis)
- medications (loop diuretic, gentamicin, chemotherapy drugs)
Causes of conductive hearing loss
- ear wax
- infection (otitis media/externa)
- fluid in the middle ear (effusion)
- eustachian tube dysfunction
- perforated tympanic membrane
- osteosclerosis
- cholesteatoma
- exostoses
- tumours
Describe audiogram in sensorineural hearing loss
both air and bone conduction readings more than 20dB below the 20dB line on the chart
Describe audiogram in conductive hearing loss
bone conduction readings will be normal but air conduction will be greater than 20dB below the 20dB line.
Define presbycusis
age related hearing loss
what type of hearing loss is prescbycusis
sensorineural - affects higher pitched first and more
RFs for presbycusis
- age
- male
- FH
- loud noise exposure
- diabetes
- hypertension
- ototoxic medications
- smoking
how to diagnose presbycusis
audiometry
Mx of presbycusis
- optimise environment
- hearing aids
- cochlear implants
Describe sudden sensorineural hearing loss (SSNHL)
hearing loss <72hrs unexplained by other causes
EMERGENCY
Causes of SSNHL
- 90% idiopathic
- infection (meningitis, HIV, mumps)
- meniere’s disease
- ototoxic medications
- MS
- migraine
- stroke
- acoustic neuroma
- Cogan’s syndrome (rare)
Ix for SSNHL
audiometry
MRI/CT head if suspecting stroke or acoustic neuroma
Mx SSNHL
immediate ENT referral within 24hrs
idiopathic- steroids (oral or intra-tympanic)
other: treat cause
Define eustachian tube dysfunction
When the tube between the middle ear and throat is not functioning properly
function of eustachian tube
equalise air pressure in the middle ear and drain fluid from the middle ear
What can eustachian tube dysfunction be related to?
viral URTI
allergies (hayfever)
smoking
Presentation of eustachian tube dysfunction
- reduced/altering hearing
- popping noises/sensation in ear
- fullness sensation in ear
- pain/discomfort
- tinnitus
- sx worsen when flying, climb, diving
Ix in eustachian tube dysfunction
- otoscopy may appear normal
If persistent - tympanometry
audiometry
nasopharyngoscopy - CT