Otology - HEARING LOSS Flashcards
What are the causes of conductive hearing loss?
External ear:
Congenital atresia (microtia)
Wax
Foreign body
Otitis externa
Tympanic membrane and middle ear:
Tympanic perforation
Otitis media
Eustachian tube blocking (nasopharyngeal tumour, allergic rhinitis)
Fixation of ossicles (fusion of ear bones)
Otosclerosis
What are the causes of sensorineural hearing loss?
Congenital causes:
Premature birth
Neonatal jaundice
Intrauterine infection
Traumatic or noise induced
Toxic - gentamicin, loop diuretics, aspirin, cytotoxics
Autoimmune hearing loss (AIED)
Cerebellopontine angle tumours - Vestibular schwannoma
Sudden onset hearing loss - herpes simplex
Menieres disease
Presbycusis (age related hearing loss)
What are the causes of acute onset hearing loss?
Otitis externa
Otitis media with effusion (glue ear)
Toxic causes
Traumatic causes
Infective causes
Vestibular schwannomas
What are the causes of more insidious onset hearing loss?
Presbycusis (age related hearing loss)
Noise induced hearing loss
Tumours
What are the causes of fluctuating hearing loss?
Middle ear effusions
Ménière’s disease
Is more copious ear discharge more associated with external ear infections or middle ear infections?
Middle ear infections
What conditions might ear discharge indicate?
Otitis externa or media
Perforated tympanic membrane
Cholesteatoma
What factors of birth and pregnancy can lead to congenital deafness?
Prematurity
Low birth weight
Neonatal jaundice
Rubella infection
What is the autosomal dominant inherited form of conductive hearing loss?
Otosclerosis
What are the medications that can cause hearing loss?
Loop diuretics
Gentamicin
Aspirin
Anti-neoplastic agents
Quinines
What are the two types of hearing loss?
Conductive hearing loss
Sensorineural hearing loss
What does Rinne’s test look for?
Conductive hearing loss
What are the two possible results from Rinne’s test?
Positive - normal - the tuning fork is still heard next to the ear when it is no longer heard when placed on the mastoid.
Negative - abnormal - the tuning fork is heard best when placed on the mastoid process.
What does Weber’s test look for?
Hearing loss - both conductive and sensorineural
It must be used in conjunction with Rinne’s test to work out which it is.
On examination of a patient with hearing loss, they have a negative result in the left ear during Rinne’s test and when Weber’s test is performed the sound lateralizes to the left. What is the likely nature of the hearing loss?
Conductive loss in the left
On examination of a patient with hearing loss, they have a negative result in the left ear during Rinne’s test and when Weber’s test is performed the sound lateralizes to the right. What is the likely nature of the hearing loss?
Combined (conductive and sensorineural) loss in the left ear
On examination of a patient with hearing loss, they have a negative result in the right ear during Rinne’s test and when Weber’s test is performed the sound lateralizes to the left. What is the likely nature of the hearing loss?
Combined (conductive and sensorineural) loss in the right ear
On examination of a patient with hearing loss, they have a negative result in the right ear during Rinne’s test and when Weber’s test is performed the sound lateralizes to the right. What is the likely nature of the hearing loss?
Conductive loss in the right
On examination of a patient with hearing loss, they have a positive result in both ears during Rinne’s test but when Weber’s test is performed the sound lateralizes to the left. What is the likely nature of the hearing loss?
Sensorineural loss in the right
On examination of a patient with hearing loss, they have a positive result in both ears during Rinne’s test but when Weber’s test is performed the sound lateralizes to the right. What is the likely nature of the hearing loss?
Sensorineural loss in the left
On examination of a patient with hearing loss, they have a negative result in both ears during Rinne’s test but when Weber’s test is performed the sound lateralizes to the right. What is the likely nature of the hearing loss?
Combined loss in the left
Conductive loss in the right
On examination of a patient with hearing loss, they have a negative result in both ears during Rinne’s test but when Weber’s test is performed the sound lateralizes to the left. What is the likely nature of the hearing loss?
Combined loss in the right
Conductive loss in the left
On examination of a patient with hearing loss, they have a negative result in both ears during Rinne’s test but when Weber’s test is performed the sound does not lateralize. What is the likely nature of the hearing loss?
Conductive loss in both ears
When you examine the tympanic membrane, what features are assessing?
Perforations
Bulging (middle ear fluid)
Retracted/sucked in (Eustachian tube dysfunction)
Colour
Inflammation (red)
Middle ear effusion (yellowish and serous, greyish in glue ear)
Light reflex (over-rated as a sign)
What is the standardized hearing test that we use?
Pure tone audiogram
If a patient is unable to undertake the pure tone audiogram, what are the other options available?
Oto-acoustic emission testing (OAEs)
Brain stem evoked response audiometry (BERA)
What is the objective test used to assess middle ear function?
Tympanometry
When might a patient who presents with hearing loss need a CT of temporal bones?
Cholesteatoma
Malformations of external ear
As well as assessing hearing and examining the ear, what else must you examine in a patient with hearing loss?
Signs of facial nerve palsy
What is otosclerosis?
Inherited disease which produces a progressive, conductive or mixed hearing loss secondary to abnormal bone metabolism in the remnants of the otic capsule in the inner ear. The most common site of attack in the ear is the fistula ante fenestra at the anterior part of the stapes footplate. The abnormal bone deposition anchors the stapes in the round window preventing normal conduction of sound.
Are males or females more affected by otosclerosis?
Females are affected twice as much.
How do patients affected by otosclerosis most often present?
In the third decade of life, with slowly, progressive, bilateral conductive deafness, tinnitus and occasional mild vertigo. Otoscopy shows a normal ear drum in most cases, however 10% have a ‘flamingo tinge to the tympanic membrane. This is caused by hyperaemia.
What investigations would you order for someone in whom you suspect otosclerosis and what would the results likely show?
Audiogram - typically shows a conductive hearing loss. In late disease however there can be a superimposed sensorineural hearing loss.
Tympanogram - typically normal
CT scanning - may show abnormal bone deposition around the cochlea with areas of radiolucency. This is called ostiospongiosus.
How do you manage someone with diagnosed otosclerosis?
Conservative - hearing aids
Surgical - stapedectomy and insertion of prosthesis
What is presbyacusis?
Irreversible sensorineural hearing loss due to age related degeneration of the hair cells. Very common. Patient will report bilateral hearing loss accompanied by tinnitus. Speech discrimination is affected first, especially when there is background noise.
How is presbyacusis diagnosed?
Mainly through history and audiological evidence of bilateral sensorineural hearing loss that is more marked in the higher frequencies.
What sounds do those with presbyacusis have particular difficulty hearing?
Speech, especially those sounds of speech which involve the higher frequencies. Sounds include ‘th’, ‘f’, ‘s’ and ‘k’
How are those with presbyacusis managed?
Provision of an appropriate hearing aid
Provision of environmental aids as well
Cochlear implantation
