1: Hearing Loss Flashcards
1
Q
What are the three types of hearing loss
A
- Sensorineural
- Conductive
- Mixed
2
Q
What causes sensorineural hearing loss
A
Defect in inner ear or vestibulocochlear nerve
3
Q
What causes conductive hearing loss
A
Defect in middle or outer ear
4
Q
When does conductive hearing loss tend to present more
A
Children
Young Adults
5
Q
When does sensorineural hearing loss tend to present
A
Middle-age
Older age
6
Q
Give 5 causes of conducting hearing loss
A
- Otosclerosis
- Otitis media
- Barotrauma
- Cerumen impaction
- External auditory meatus atresia
7
Q
What is cerumen impaction
A
Build-up of wax in the external auditory canal
8
Q
What are 6 causes of sensorineural hearing loss
A
- Ototoxicity
- Meniere’s Disease
- Acoustic neuroma
- Presbycusis
- Inner ear infection (Mumps, measles, meningitis)
- Noise-induced hearing loss
9
Q
Otosclerosis
A
Overgrowth of the stapes causing it to fix to the oval window
10
Q
What is otitis media
A
Bacterial or viral infection of the middle-ear
11
Q
What is barotrauma
A
Failure to equalise atmospheric pressure with the middle ear
12
Q
How will otosclerosis present
A
Progressive conducting hearing loss. 70% develop it in the second ear.
13
Q
What symptom is specific to otosclerosis
A
Paracusis Willisi
14
Q
What is paracusis willisi
A
Patient’s hear better in noisy compared to quiet environments
15
Q
What sign is seen on the tympanic membrane in otosclerosis
A
Schwartz sign
16
Q
What is the schwartze sign
A
Red-blue tinge to tympanic membrane
17
Q
In what age does otitis media present
A
6-24m following URTI
18
Q
How will barotrauma to the ear present
A
sudden-onset stabbing pain in the ear. Tinnitus and hearing loss. Bleeding from the canal indicates perforation of the ear drum.
19
Q
How does presbycusis present
A
High-frequency hearing loss
20
Q
How does noise-induced hearing loss present
A
Gradual high-frequency hearing loss. Often unable to hear in noisy environments
21
Q
How does meniere’s disease present
A
Episodes lasting to minutes-hours of:
- Vertigo (Horizontal Nystagmus)
- Sensorineural hearing loss
- Tinnitus
22
Q
What nerves are affected initially in acoustic neuroma
A
- vestibular
- cochlear
23
Q
What nerves are affected late in acoustic neuroma
A
- trigeminal
- facial
24
Q
How will early symptoms of acoustic neuroma present
A
Vestibular - vertigo
Cochlear - unilateral tinnitus, hearing loss
25
How will late symptoms of acoustic neuroma present
Trigeminal - facial parasthesia
Facial - unilateral paralysis
26
Explain investigations in work-up of hearing loss
1. Inspection
2. Whispered hearing test
3. Rinne's
4. Weber's
5. Otoscopy
6. Pure tone audiometry
7. Tympanometry
27
What is looked for when inspecting the ear in hearing loss
Otitis externa
| Cerumen Impaction
28
What is the whispered voice test
Gross hearing assessment
29
Explain the whispered voice test
- Stand 60cm behind someones ear. Rub tragus in the ear not being tested.
- Whisper a number into the other ear.
- Repeat this 3-times. If the patient can hear in 2/3 it indicates their hearing is >12dB
30
In the whispered voice test, if having to use a conversational voice how many decibels can they hear
48db
31
In the whispered voice test, if having to use a loud voice how many decibels can they hear
72db
32
Explain weber's test
Place a 512Hz tuning fork in the middle of the patient's head and ask them where they hear it loudest
33
What is a mnemonic to remember results of weber's test
SICA
34
In sensorineural hearing loss, where will the sound localise to
It would localise to the intact ear
35
In conductive hearing loss, where will the sound localise to
It would localise to the affected ear
36
What is a rinne's positive test
When air conduction is better than bone conduction
37
What can cause a rinne's positive test
- Normal
| - Sensorineural hearing loss
38
What is a rinne's negative test
Bone conduction > Air conduction
39
What causes a rinne's negative test
Conductive hearing loss
40
Explain pure tone audiometry
- Patient is placed in a sound-proof room
- Head phones deliver sounds at increasing frequencies
- It is played initially above hearing threshold and increase in 10db increments until a 50% response rate is obtained
- Transducer can be used to obtain bone conduction
41
What goes on the X-axis in pure tone audiometry
Frequency (Hz)
42
What goes on the Y-axis in pure tone audiometry
Decibels
43
What is normal hearing range on audiometry
Anything above 20db
44
Explain conductive hearing loss on audiometry
Auditory threshold increased in air conduction, normal bone conduction
45
What does conductive hearing loss on audiometry indicate
Middle or external ear pathology
46
Explain presentation of otosclerosis on audiometry
- Air conduction is reduced
| - Bone conduction shows a characteristic notch at 2,000Hz called cahart notch
47
Explain how presbycusis will present on audiometry
Decrease in air and bone conduction at higher frequencies
48
Explain how noise-induced hearing loss presents on audiometry
Decrease in noise and air conduction at 4,000Hz
49
What is tympanometry also referred to as
Acoustic impedance audiometry
50
What is tympanometry
Method to measure pressure in the middle-ear
51
Explain the procedure of tympanometry
- In a normal ear compliance of the ear drum (and hence amount of fluid in mL displaced for a particular sound) peaks when middle ear pressure equals canal pressure
- A probe with an air tight seal is put into the meatus - the amount of acoustic signal reflected back at points is used to generate a graph of compliance
52
What is a normal ear type on tympanometry
type A
53
What is type A
There will be a peak which will then decrease. It indicates a normal ear where ossicles are intact and no fluid in the middle-ear
54
How will type AD present
Reduced peak amplitude compared to type A. But, the peak is still present
55
Explain type AD
There is disruption of the ossicles or flaccid portion of the tympanic membrane
56
How will type B tympanometry present
Completely flat (there will be no peak)
57
Explain type B tympanometry
There is reduced compliance of the tympanic membrane due to fluid in the middle ear - meaning all sound will be reflected back
58
If a type B tympanometry at normal pressure what is the underlying pathology
Otitis Media
59
If a type B tympanometry at high pressure what is the underlying pathology
Grommets
60
If a type B tympanometry at low pressure what is the underlying pathology
Ceremen Impaction
61
What is type C tympanometry
There is a shift in peak of negative middle-ear pressure
62
What causes type C tympanometry
Resolving otitis media
63
What are the indications for MRI in hearing loss
1. Adult with sensorineural hearing loss and localising signs (facial paraesthesia)
2. Adult with asymmetrical sensorineural hearing loss of >15dB difference
64
What is an MRI trying to exclude in hearing loss
Acoustic neuroma
65
In terms of anatomy, how can the ear be divided
External ear
Middle ear
Inner ear
66
What are the two parts of the external ear
1. Auricle (Pinna)
| 2. External auditory meatus
67
What is the function of the auricle
Directs sound towards the external acoustic meatus
68
What is the helix
Round cartilaginous structure
69
What is the concha
Depression in the middle of the auricle
70
What does the concha lead to
The concha continues as the external acoustic meatus into the skull
71
What is the external acoustic meatus
Tube that connects the concha to the tympanic membrane
72
What is the tympanic membrane
Connective tissue that enables middle ear to be to be observed
73
What is the point where the malleus attaches to the tympanic membrane called
Umbo
74
Where is the middle ear
Tympanic membrane to inner ear
75
What is the function of the middle ear
Transmits vibrations from the tympanic membrane to the inner ear via ossicles
76
What are the two components of the middle ear
Tympanic cavity
Epitympanic recess
77
What is the tympanic cavity
Contains the ossicles: stapedius, malleus and incus
78
What is contained lateral to the epitympanic recess
Mastoid air cells
79
What Is the role of mastoid air cells
When pressure in middle ear is low - they can release air acting as a buffer
80
What is the acoustic reflex
In response to loud noise the stapedius and tensor tympanic will contract - inhibiting vibrations of auditory canal and transmission of sound
81
What is the Eustachian tube
Connects the nasopharynx to the middle ear
82
What is the role of the Eustachian tube
To equalise pressure of middle ear
83
What is the problem with the Eustachian tube
Acts as source of infection pass to the middle ear
84
What are the 2 functions of the inner ear
- Convert mechanical signals into electric signals for hearing
- Maintain balance
85
What are the two components of the inner ear
1. Bony Labyrinth
| 2. Membranous Labyrinth
86
What is the bony labyrinth
Series of bone cavities in petrous part of temporal bone made of cochlea, vestibule and semi-circular canals filled with perilymph
87
What is the membranous labyrinth
In body of bony labyrinth = made of cochlear duct, semi-circular ducts, utricle and saccule - filled with endolymph
88
What are the two openings in the inner ear
Oval window
| Round window
89
What is the oval window
Connects vestibule and middle-ear
90
What is the round window
Connects middle-ear and scala tympani
91
What are the 3 parts of the bony labyrinth
Vestibule
Cochlear
Semi-circular canals
92
What does the vestibule contain
Utricle
Saccule
= both part of membranous labyrinth
93
What does the cochlea contain
Cochlea duct - used for hearing
94
What are the 3 semi-circular canals and their role
Posterior
Anterior
Lateral
= role in balance
95
What type of fluid is the bony labyrinth filled with
perilymph
96
What type of fluid is the membranous labyrinth filled with
endolymph
97
what is the membranous labyrinth made of
- Utricle
- Saccule
- Semi-circular ducts
- Cochlea duct
98
what is the cochlea duct also known as
Organ of corti
99
what is the role of the saccule
Detects acceleration-deceleration of the head in a vertical plane
100
what is the role of the utricle
Detects acceleration-deceleration of the head in a horizontal plane
101
explain semi-circular ducts
on moving the head, the flow of endolymph changes speed or direction. Sensory receptors in the ampulla detect this and send signals to the brain enabling processing of balancing.
102
How is the cochlea organised
Tonotropic - meaning different frequencies are processed at different parts
103
Where are high frequencies processed
Base
104
Where are low frequencies processed
Apex
105
What is a mnemonic to remember pathway of hearing
E.COLI
106
Explain pathway of hearing
- Eight nerve
- Cochlear nucleus
- superior Olive
- Lateral lemniscus
- Infeiror colliculus
107
What causes conductive hearing loss
Defect in outer or middle ear
108
What are the outer ear causes of conductive hearing loss
- Barotrauma
- Chronic OM resulting in rupture of TM
- External auditory canal atresia
109
What are the 2 middle ear causes of conductive hearing loss
Cerumen impaction
Otitis media
Otosclerosis
110
What is otosclerosis
Overgrowth of bone of the stapes causing it to fix to the oval window
111
Explain the aetiology of otosclerosis
Autosomal dominant condition with incomplete penetrance
112
What type of patients get otosclerosis
Young female patients:
| 20-40
113
How will otosclerosis present clinically
- Progressive bilateral conductive hearing loss
- Tinnitus (75%)
- Mild vertigo (25%)
114
What is a specific symptom of otosclerosis
Paracusis Willsi = patient's hear better in noisy environments
115
What investigations are ordered for otosclerosis
1. Otoscopy
2. Rinne and Weber's
3. Pure Tone audiometry
4. Tympanometry
116
What will 10% of people have on otoscopy in otosclerosis
Schwartz sign = hyperaemia behind tympanic membrane seen as red discolouration
117
How will rinne and weber's test present in otosclerosis
- Rinne negative
| - Weber's = localises to affected ear
118
What will be seen on pure tone audiometry in otosclerosis
Cahart notch = increase in bone conduction threshold (dip in curve) at 2,000Hz
119
What is first-line management for otosclerosis
Bone Anchored Hearing Aids
120
What is surgical management of otosclerosis
Stapedotomy
| Stapedectomy
121
What is stapedotomy
Partial remove stapes
122
What is stapedectomy
Removal stapes and replacement with prosthesis
123
Explain surgery in otosclerosis
Surgery is preferred, however it can only be performed in the worst hearing ear - as contralateral previous surgery is a contraindication.
124
What is sensorineural hearing loss due to
damage to inner ear or vestibular-cochlear nerve
125
What is the commonest cause of SNHL
presbycusis
126
What is presbycusis
age-related bilateral high-frequency hearing loss
127
In which age does presbcycusis occur
incidence increases with age
128
When is hearing worse in presbycusis
noisy environments
129
What causes presbycusis
progressive damage to the organ of corti
130
What will be seen on pure tone audiometry in presbycusis
decrease in air and bone conduction
131
How is presbycusis managed
hearing aids
132
What is noise-induced hearing loss
Hearing loss due to exposure to loud noises
133
What are the two causes of NIHL
- Repeated exposure to sounds >85dB
| - One-off exposure to sounds > 120-150dB
134
How does NIHL present
- Often with loss of high-frequency sounds first
| - Difficultly hearing in loud enviroments
135
Explain pathophysiology of NIHL
- Repeated exposure damages sterocilia on the organ of corti.
- One off exposure to loud noice can cause rupture of TM and conductive hearing loss
136
What is used as prophylaxis for NIHL
Noise-cancelling headphones
137
What is used to manage NIHL
Hearing aids
138
What is menière's disease
impaired re-absorption of endolymph in the membranous labyrinth leading to accumulation and dilation of the system = endolymphatic hydrops
139
What age is meniere's disease most common
40-60y
140
How does meniere's disease change with age
Episodes decrease with age
141
Explain presentation of meniere's disease
Acute, Attacks usually last 2-4h and present with triad of:
- tinnitus
- unilateral SNHL
- peripheral vertigo
this is associated with
- Horizontal nystagmus
- aural fullness
- positive rhomberg test
142
How will meniere's disease present on audiometry
Reduced bone and air conduction in the affected ear. Often, low-frequencies are affected first
143
What are two other investigations may order for menière's disease
- Elecetrocohleography
| - Posterior fossa MRI
144
What is electrocochleaography
- Looks at electrical impulses evoked from vestibulocochlear nerve in response to sound
145
What is used to treat acute attacks of meniere's disease
Buccal bethistine
146
What is used as prophylaxis for meniere's disease
Prochlorperazine
147
If meniere's disease persists what is indicated
1. Insertion of gentamicin via a grommet
2. Labryinthectomy
3. Vestibular neurectomy
148
What are the risks of surgical procedures for menieres disease
Can cause total deafness
149
what else should be considered in management of meniere's disease
Driving - individuals should inform DVLA and not drive until symptoms controlled
150
over what time frame do symptoms resolve in majority of patients
5-10years
151
what is an acoustic neuroma
benign tumour of schwann cells surrounding vestibular.N
152
what is the median age of acoustic neuroma onset
50
153
what % of CPA tumours are acoustic neuromas
90
154
what does bilateral acoustic neuromas indicate
NF2
155
what chromosome is mutated in neurofibromatosis 2
chromosome 22
156
what are the 4 tumours common in NF2
1. Meningiomas
2. Ependymomas
3. Bilateral vestibular
schwannoma
4. Multiple intracranial
schwannoma
157
are acoustic neuromas unilateral or bilateral
unilateral (90%). Bilateral acoustic neuromas are only associated with NF2
158
what nerve is affected early in acoustic neuromas
vestibular-cochlear nerve
159
what are the 3 early symptoms of acoustic neuroma
- Unilateral tinnitus
- Unilateral SNHL
- Dizziness
160
why do individuals with acoustic neuroma not get vertigo
Due to the slow-growing nature of the tumour - the body often compromises
161
what are the late symptoms of acoustic neuromas caused by
Due to damage to trigeminal (CN5) and facial (CN7) nerves
162
what 2 symptoms are caused by compression of CN5 in acoustic neuroma
- Loss of corneal reflex
| - Facial parasthesia
163
what symptom is caused by compression of CN7 in acoustic neuroma
Facial paralysis
164
will the forehead be affected in CN7 damage due to acoustic neuroma
The forehead will be affected as it is a LMN paralysis
165
what is the risk of acoustic neuromas
can compress other posterior fossa structures including the cerebellum and 4th ventricle
166
what will compression of cerebellum cause
Ataxia
167
what will compression of the 4th ventricle
Hydrocephalus
168
who should suspected acoustic neuromas be referred to
urgent referral to ENT
169
how are acoustic neuromas investigated
- Rinne and Weber's
- Pure tone audiometry
- MRI of CPA
170
how will acoustic neuromas present on rinne and weber's test
SNHL:
- +ve Rinne's
- Weber's = intact ear
171
how will acoustic neuromas present on pure-tone audiometry
Decrease in air and bone conduction
172
what is main investigation of acoustic neuromas
MRI of CPA
173
what are indications for MRI in CPA
- Asymmetry in SNHL between ears >15dB
| - SNHL and other features
174
what is primary management for acoustic neuromas
- Active surveillance = MRI 6-12m
175
what is second-line management for acoustic neuromas
Stereotactic radiosurgery
176
when is stereotactic radio surgery indicated
1. Tumour growth
| 2. Significant SNHL
177
What ototoxic effects do antimalarials and aspirin have
Temporary hearing loss
| Tinnitus
178
What ototoxic effects do loop diuretics and macrolides have
Temporary hearing loss
179
What ototoxic effects do aminoglycosides have
Permanent hearing loss and vestibular effects
180
What ototoxic effects do antineoplastics have
Permanent hearing loss
181
what is the definition of sudden hearing loss
loss of more than 30db in 3 contagious frequencies that onsets in less than 3d
182
how can aetiology of sudden onset hearing loss be divided
unilateral sudden hearing loss and bilateral
183
what is the 1 cause of bilateral sudden-onset sensorineural HL
autoimmune
184
what are 7 causes of sudden-onset hearing loss
- Vascular
- NIHL
- Glue ear
- Acoustic neuroma
- Ototoxicity
- Mumps
- Ossicular discontinuity
185
what is glue ear, what age does it present, how does it present
1. Otitis media with effusion
2. Peaks at 2-years
3. Conductive hearing loss following URTI
186
how will glue ear present on otoscopy
Effusion in middle ear
187
what type of hearing loss does glue ear cause
Conductive
188
what cause ossicular discontinuity
Disruption of ossicles following trauma
189
what type of hearing loss is present in ossicular discontinuity
Conductive
190
what type of tympanometry is present in ossicular discontinuity
Ad = flatter peak compared to type A
191
what type of sudden hearing loss will vascular or autoimmune lead to
SNHL
192
if no cause is found for sudden hearing loss what is it called
idiopathic sudden sensorineural hearing loss (ISSHL)
193
Explain referral for sudden onset hearing loss
1. Develops sudden hearing loss in <3d in the past 30d = refer to ENT in 24h
2. Develops sudden hearing loss in <3d more than 30d ago = refer to ENT in 2W
3. Worsening of pre-existing hearing loss = refer to ENT in 2W
194
What is often given for sudden onset hearing loss
High-dose steroids = Prednisolone (80mg)
195
If prednisolone is ineffective, what else may be offered
Short hyperbaric oxygen therapy
196
What are 3 unilateral causes of progressive hearing loss
- Otosclerosis
- Nasopharyngeal carcinoma
- Acoustic neuroma
197
In which ethnicity are nasopharyngeal carcinomas more common
Chinese/Hong-Kong
198
How do nasopharyngeal carcinoma present clinically
- Unilateral nasal lump
- Neck lumps
- Epistaxis
- Conductive hearing loss = middle ear effusion on otoscopy
199
What are two bilateral cases of progressive hearing loss
NIHL
| Presbycusis
200
When are hearing aids offered
If hearing loss is impacting ability to communicate
201
What is the mechanism of behind the ear hearing aid
Amplifies sound to assist with hearing
202
What are bone anchored hearing aids
Sound is transmitted directly to the cochlea via bone conduction
203
What are cochlear implants indicated for
SNHL who has not benefitedd to conventional hearing aids
204
What are audio induction loops
sound system where hearing loop provides magnetic, wireless signal picked up by hearing aid when set to T. It has a microphone and amplified.
