21 EAR DISEASE AND HEARING LOSS Flashcards
Describe the role of the Eustachian tube and why it doesn’t work as well in infants.
Connect to the air filled middle air and the nasopharynx. Aerates the middle ear and equalises pressures between outer and middle ear. Does not work as well in infants as is more horizontal.
What percentage of people have some degree of hearing loss in Aotearoa
10%, 6.6% disability due to hearing loss and 0.7% report disability due to deafness.
What hx is needed is assessment of hearing loss
Age, severity, onset, rapid/gradual, constant/ fluctuating. ANy precipitating factors- trauma, noise, drugs.
Family hx.
Associated symptoms: tinnitus, vertigo, aural fullness, headaches, facial pain
Examinations of hearing
Otoscopy
Clinical tests
Tuning fork tests
Describe otoscopy
Medical device used to look at outer ear, ear canal, tympanic membrane for things that may cause conductive loss
Clinical test
Whisper test
Describe rinne test
Determines unilateral hearing loss. Detects air conducted and bone conducted hearing using tuning fork next to pinna and on mastoid bone. Air conducted sound should be greater than bone conducted. picks up conductive hearing loss.
Describe the weber test
Tuning fork placed on middle of forehead, above upper lip, under or on top of head equidistance apart from ears. Sound should be heard equally in both ears. Used to determine which ear hearing loss is in.
List the investigations used to assess for hearing loss
Audiogram Otoacoustic emission (outer hair cells making sound) Auditory brainstem response CT/ MRI Electrococleargraphy Bloods Genetic testing Cardia, renal opthamalgic consult
What are the three types of hearing loss
Conductive, sensorineural, central auditory disorder
What investigative findings will you see with a conductive hearing loss
Air bone gap on audiogram
Negative rinne test with weber test referring to affected ear. Tympanogram will show reduced compliance and reflexes with be absent in impedence probe in deaf ear.
Causes of conductive hearing loss
Congenital- malformation. Acquired- exostosis where bones grow over in exposure to cold.
Inflammatory- Acute otitis media and otitis media with effusion (glue ear)
Tumour
Trauma
What will you see on sensorineural hearing loss
No air bone gap. Normal rinne, Webbe will refer to better ear. Normal tympanogram. Altered auditory brain stem response on affected side.
What are some things that may causes a sensorineural loss
Most due to sensory cell damage in cochlear (age, noise exposure).
Genetic malformation (e.g. connexion 26, important in mainting K+ concentration gradient)
Inner ear infection
Ototoxic drugs- aspirin, diuretics, anticancer drugs, some antibiotics.
Trauma.
Tumour (vestibular schwannoma)
Describe symptoms of a sensorineural hearing loss
Poor discrimination of frequency of speech Distortion Loudness imbalance Different frequencies missing Tinnitus
