41. Change in hearing Flashcards
Index conditions
a) Conductive deafness
b) Sensorineural deafness
c) Tinnitus?
a) Earwax (cerumen), otosclerosis, otitis media, cholesteatoma
b) Congenital, age-related (presbyacusis), occupational, Meniere’s, drug toxicity (e.g. aminoglycosides), acoustic neuroma, meningitis
Management of deafness in children.
a) Congenital
b) Acquired - usual cause?
c) Unilateral SNHL
d) Bilateral/severe SNHL
a) Cochlear implants/hearing aids
b) Otitis media with effusion (glue ear) - grommet?
c) Hearing aids, supportive (speech therapy, etc.)
d) Cochlear implants
Management of deafness in adults.
a) Chronic
b) Acute
c) Unilateral SNHL - investigation?
d) Unilateral CHL - investigation?
a) Unilateral symptoms - MRI to exclude acoustic neuroma, if associated with sinus/lung/kidney issues - rule out AI condition with antibody screen.
- Hearing aid
b) - Rule out neurology (CVA, MS) with MRI, consider drug causes/injury
c) MRI head/IAM for acoustic neuroma
d) Once excluding simple pathology (eg. earwax, infection), may need to do rhinoscopy to exclude nasopharyngeal tumour
Rinne’s and Weber’s tests.
a) Frequency of tuning fork used (why?)
b) Weber’s test - purpose?
c) Rinne’s test - purpose?
d) In normal ears: is AC or BC better?
e) In SNHL: is AC or BC better?
f) In CHL: is AC or BC better?
g) How does bone conduction work?
a) 512 Hz - approximately human speech frequency; also limited overtones and vibro-tactile element
b) Lateralisation
c) Tests the perceived loudness of air and bone conduction, to differentiate SNHL from CHL
d) AC > BC
e) AC > BC
f) BC > AC
g) - Cochlea is stimulated directly via bone vibration, rather than through the middle ear
- In CHL, the defect is in middle ear conduction; hence, bone conduction bypasses the middle ear and is better than air conduction in CHL
Weber’s test: interpretation
a) Normal ears - result? (may also be like this in…?)
b) If lateralisation to the right ear - 2 possibilities
c) If lateralisation to the left ear - 2 possibilities
a) No lateralisation; heard the same in both ears (also the case in symmetrical bilateral hearing loss)
b) SNHL in L ear, or CHL in right ear
c) SNHL in R ear, or CHL in left ear
Rinne’s test: interpretation
a) Rinne’s positive* = ? (2 possible diagnoses?)
b) Rinne’s negative = ? (diagnosis?)
c) Cause of a false Rinne’s negative
- Note: Rinne’s is the only medical test where a ‘positive’ test result, is actually the normal one
a) AC > BC (normal, or SNHL)
b) BC > AC (CHL)
c) Severe SNHL in test ear, with bone conduction transmitted to the good (contralateral) ear.
- Should weight against Weber result, and also ask patient which ear they heard the bone conduction in
Audiogram: basics
a) Frequency range of normal hearing
b) Normal frequency range of spoken voice
c) Two axes of an audiogram (with units)
d) The red ‘O’ line and blue ‘X’ line correspond to…?
e) If there is also a red ‘>’ line, these correspond to…?
f) The difference between the O/X and >/< lines is called the…?
g) Hearing loss is symmetrical if the red ‘O’ and blue ‘X’ lines are within what volume of each other?
a) 20 - 20,000 Hz
b) 250 - 8,000 Hz
c) X-axis: frequency (Hz); Y-axis: volume (dB)
d) Air conduction: Red = Right ear, Blue = left ear
e) Bone conduction (colour code as above; Red = Right)
f) Air-bone gap
g) 10 dB
Audiogram: interpretation
a) If there is reduced hearing, and an air-bone gap - this indicates what type of hearing loss?
b) If there is no air-bone gap, with bone conduction within normal hearing range - type of hearing loss?
c) If there is an air-bone gap, but with bone conduction BELOW normal hearing range - type of hearing loss?
d) Noise-induced SNHL - usual pattern?
e) Presbyacusis - usual pattern?
f) Otosclerosis - usual pattern?
a) Conductive (CHL)
b) Sensorineural (SNHL)
c) Mixed hearing loss (conductive and sensorineural)
d) SNHL (no air-bone gap); Drop at and around ~ 4 kHz (normal elsewhere)
e) SNHL (no air-bone gap); Higher frequencies affected most (downward slope from around 1 kHz +)
f) CHL (air bone gap); Lower frequencies affected most; may also have Carhart’s notch (drop in BC ~ 2000 Hz)
Hearing loss: grading
- (corresponding to what sounds?)
- No hearing loss: < 25 dB
- Mild hearing loss: 25 - 39 dB (can’t hear whispering)*
- Moderate hearing loss: 40 - 69 dB (can’t hear normal speech)
- Severe hearing loss: 70 - 95 dB (can’t hear shouting)
- Profound hearing loss: > 95 dB (can’t hear sounds that would be painful for someone with normal hearing)
- Whispering ~ 30 dB
Normal speech ~ 60 dB
Painful threshold ~ 140 dB
Presbyacusis.
a) Type of hearing loss
b) Risk factors
c) Presentation
d) Confirming the diagnosis
e) Other possible opportunistic investigations
f) Management
a) Sensorineural (should be symmetrical)
b) Older age, FHx, smoking, ototoxic drugs, noise exposure without ear protection, HTN, diabetes, alcohol
c) - Usually with struggling to understand speech, especially where there is background noise
- Relatives may notice first
- When hearing becomes marked, may have tinnitus
d) Pure tone audiometry:
- graph drops off at the higher frequencies
- no air-bone gap (= sensorineural)
e) - Bloods: FBC, glucose/HbA1c, lipids, renal function
- BP measurement
f) - General: education, reassurance, limit background noise, lipreading, repeat things, misheard/ misunderstood, assistive devices (eg. vibrating alarm clock, flashing smoke alarms)
- Manage treatable coexisting conditions (eg. earwax)
- Hearing aids (usually behind the ear)
- Cochlear implant (only for bilateral SNHL, not responding to hearing aids)
Cochlear implant
- who is suitable for referral?
Bilateral SNHL not responding to hearing aids
Deafness in children.
a) Causes of SNHL in children
b) Causes of CHL in children
c) Presentation
d) Investigations
e) Management
a) SNHL (~ 50%):
- mostly congenital (chromosomal, genetic, TORCH infection, maternal drug use/ teratogenicity)
- perinatal (hypoxia, hyperbilirubinaemia, sepsis, premature/ LBW),
- postnatal insult (head injury, meningitis)
b) CHL (~ 50%)
- Glue ear - generally reversible
- TM perforation (usually due to chronic infection)
- Wax (less common in kids)
c) - Newborn hearing screening test
- Parental concern - eg. lack of response to sound
- Speech impediment / language delay
- Behavioural problems or problems at school (eg. daydreaming)
- Stigmata of other disease (eg. Turner’s, Down’s)
- Recurrent URTI/ mouth breathing/ chronic cough (post-nasal drip) - may indicate large adenoids and glue ear
d) - Audiometry + Tympanometry
- If suspicious of lesion - MRI head
e) General management.
- Family education and support
- Aids - hearing aids, radio aids (teacher wears transmitter, pupil wears receiver), Cochlear implant
- Teaching - lip reading and BSL (British sign language)
- Speech therapy - ensure normal speech development
Treat reversible causes.
- Glue ear - grommet insertion, adenoidectomy
- Ossicular dysfunction/ cholesteatoma - surgery
Tympanometry.
a) What does it assess?
b) How does it work?
c) Normal graph appearance and pressure range
d) Flat line with normal canal volume - diagnosis?
e) Flat line with excess canal volume - 2 DDx?
f) Negatively shifted graph (peak pressure < -100)
a) Middle ear functioning.
b) It looks at the flexibility (compliance) of the eardrum to changing air pressures, indicating how effectively sound is transmitted into the middle ear.
c) Symmetrical peak around 0 (range -100 to +100)
d) Glue ear
e) TM perforation, grommet in situ
f) Eustachian tube dysfunction (may be seen just before or after effusion)
Otitis media.
a) Types of otitis media with clinical features
b) Cause, risk factors and pathogens
c) Presentation and demographics
d) Relief of pain may indicate…? (common accompanying symptom?)
e) Investigations
f) Who to refer to hospital?
g) Management
h) Complications - common, less common, rare
a) - Acute OM: acute otalgia, fever, etc.
- Suppurative OM: pus behind TM (~ 5% TM perforation)
- OME (glue ear): secondary to chronic OM, causing build-up of glue-like fluid behind an intact TM (no acute inflammation)
b) Usually spread from URTI (via ET);
- pathogens: h. influenzae, streptococcus, moraxella, viral (eg. RSV)
- RFs: young age (< 3), male, parental smoking, daycare attendance, craniofacial abnormalities
c) Peak age: < 3 years (pre-school)
- Otalgia (young children may pull at ear), fever, malaise, N/V, poor feeding, coryzal, discharge
- Signs: inflamed canal/TM, bulging/yellow TM, yellow discharge, red pinna
- OME: no inflammation but CHL
d) TM perforation; may then have yellow/green ear discharge
e) - No CHL - usually no investigation required
- ?Glue ear + CHL: audiometry / tympanometry
f) Admit if < 3 months with fever, systemically unwell, or fear of complications
g) - General: paracetamol/NSAIDs if pyrexial, fluids, reassure that self-limiting
- No ABx/ delayed ABx (1st line: 5/7 amoxicillin)
- Who to prescribe immediate ABx: systemically unwell, risk of complications, >4 days
h) - Common: glue ear (+ CHL), scarring, TM perforation
- Less common: cholesteatoma, mastoiditis
- Rare: meningitis, sepsis, or facial nerve paralysis
Glue ear (OME).
a) What is it?
b) Causes and risk factors
c) Presentation
d) Signs o/e
e) Investigations and findings
f) Management
g) Who should receive grommets? (possible complications of grommets)
h) What other surgery may be considered?
a) Chronic build-up of fluid behind the TM, without any active acute inflammation
b) Usually post-acute otitis media
- Risk factors: young age (1 - 6 years), ET dysfunction, large adenoids, persistent or recurrent URTI, cranio-facial abnormalities (eg. cleft palate, syndromes)
c) - Usually hearing loss: mishearing, communication difficulty, listening to the TV at high volumes; lack of concentration, withdrawal, impaired speech and language development, impaired school progress
- May have intermittent ear pain/ popping
- Hx of recurrent acute OM/ URTI, mouth breathing, etc.
d) - Otoscopy: retracted TM, loss of light reflex on TM, yellowish TM, fluid level on TM, no active inflammation
- Weber’s: lateralises to bad ear
- Rinne’s: BC > AC
e) - Note: watch and wait for 3 months (as often recover spontaneously)
- Audiometry: CHL (air-bone gap)
- Tympanometry: flat line (no peak)
f) - Reassure that usually resolves with no treatment (50% resolve within 3 months and 95% within 1 year)
- Advice: reduce background noise, talk directly to child, support with speech and language development, avoid parental smoking
- Manage congestion: nasal drops/spray
- Otovent to equalise pressures
- If non-resolving: surgery
- If surgery contraindicate: hearing aid
g) - Persistent bilateral OME lasting 3+ months
- Hearing loss in the best ear of 25-30 dB or worse
- Children with better hearing but who have social, educational or developmental difficulties may exceptionally also benefit from surgical treatment
- Complications: tympanosclerosis, infection, fall out
h) Adenoidectomy if recurrent URTI is a feature
