Session 7 Flashcards
1
Q
What are symptoms and signs of ear pain?
A
- Otalgia - ear pain, can be referred
- Discharge
- Hearing loss (conductive or sensorineural)
- Tinnitus - perception of hearing sound with no external source
- Vertigo - hallucination of movement
- Facial nerve palsy - facial nerve runs through petrous bone
2
Q
What makes up the external ear?
A
- Pinna seen on outside of head
- External auditory meatus (ear canal)
- Skin-lined
3
Q
What makes up the middle ear?
A
- Air filled cavity
- Ossicles
- Lined with respiratory epithelium (pseudostratified columnar ciliated epithelium with goblet cells)
4
Q
What is the tympanic membrane?
A
- Boundary between external and middle ear
5
Q
What connects the middle ear to the nasopharynx?
A
- Pharyngotympanic tube (Eustachian tube)
6
Q
What are the names of the ossicles found within the middle ear?
A
- Stapes
- Malleus
- Incus
7
Q
What makes up the inner ear?
A
- Cochlea
- 3 semi-circular canals orientated at 90o to each other
- Fluid filled
8
Q
Which nerve carries special sense for hearing and balance?
A
- Vestibulocochlear nerve
9
Q
Why is the ear a common site of referred pain?
A
- Many nerves that carry general sensation from the ear also carry general sensation from other parts of the body
- Pathology of these sites can be interpreted by the body as ear pain
10
Q
Branches of which nerves can cause referred pain to the ears?
A
- Cervical spinal nerves (C2/C3)
- Vagus
- Trigeminal (auriculotemporal)
- Glossopharyngeal (tympanic)
- Small contribution from CN VII
11
Q
What other conditions could be responsible for otalgia if the ear is normal on examination?
A
- TMJ dysfunction (trigeminal nerve branch C)
- Diseases of oropharynx (glossopharyngeal nerve)
- Diseases of larynx and pharynx including cancers (glossopharyngeal and vagus nerves)
12
Q
What is the role of the external ear?
A
- Collects, transmits and focuses sound waves onto the tympanic membrane
- Tympanic membrane vibrates
13
Q
What can cause pinna abnormalities?
A
- Congenital
- Inflammatory
- Infective
- Traumatic
14
Q
If a patient presented with facial palsy and a painful red ear with vesicles, what would your diagnosis be?
A
- Ramsay-Hunt syndrome
15
Q
What is perichondritis?
A
- Occurs due to infection involving cartilage of ear
- Provides blood supply to cartilage
- Caused by ear piercing or insect bites
- Ear can be painful, red or swollen
- Treat with antibiotics
16
Q
What is pinna haematoma?
A
- Accumulation of blood between cartilage and its overlying perichondrium
- Due to blunt injury so common in contact sports
17
Q
What kind of haematoma is a pinna haematoma?
A
- Sub perichondral haematoma
- Blood strips perichondrium off cartilage
- Deprives cartilage of blood supply
- Blood pushes against cartilage
- Leads to pressure necrosis of tissue
18
Q
How is pinna haematoma treated?
A
- Drainage (aspirate with a needle)
- Prevent reaccumulation of blood/ re-apposition of two layers
19
Q
What happens if a pinna haematoma is left untreated?
A
- Fibrosis
- New asymmetrical cartilage development
- Cauliflower deformity
20
Q
What epithelium lines the external acoustic meatus?
A
- Keratinising, stratified squamous epithelium
- Continuous onto lateral surface of tympanic membrane
21
Q
Describe the structure of the external acoustic meatus
A
- Outer 1/3 is cartilaginous
- Inner 2/3 are bony
- Sigmoid shape
22
Q
Describe the cartilaginous part of the external acoustic meatus?
A
- Hair, sebaceous and ceruminous glands line cartilage part
- Acts as a barrier to foreign objects
- Ceruminous glands produce ear wax
23
Q
Outline the self-cleaning function of the external acoustic meatus
A
- Desquamation and skin migration
- Laterally off tympanic membrane out of canal
- Keeps ear canal free of debris
24
Q
What should you see on a normal otoscopic view?
A
- Cone of light
25
What common conditions can affect the external acoustic meatus?
- Wax/foreign bodies
- Otitis externa
26
What causes otitis externa?
- Also known as swimmer's ear
- Moisture in external acoustic meatus becomes a breeding ground for bacteria
- Treated with antibiotics
27
What is malignant otitis externa?
- Very rare
- Potentially life-threatening
- Infection becomes invasive and erodes bone of ear
28
What are common abnormalities of the tympanic membrane?
- Bulging secondary to bacterial acute otitis media
- Build-up of pus and exudate in middle ear causes tympanic membrane to bulge into external acoustic meatus
- Otitis media with effusion
- Tympanic membrane retracted (sucked inwards) due to air bubbles when fluid accumulates in middle ear cavity
29
What is cholesteatoma?
- Retraction of pars flaccida of tympanic membrane forms a sac/pocket
- Traps stratified squamous epithelium and keratin
- This proliferates
- Forms cholesteatoma
- This slowly grows and expands
30
What leads to cholesteatoma?
- Chronic eustachian tube dysfunction
- Negative pressure created
- Pulls pocket into middle ear
31
What are the symptoms of cholesteatoma?
- Painless, often smelly otorrhea (ear discharge)
- Hearing loss
32
What are the more serious consequences of cholesteatoma?
- Enzymatic bony destruction
- Erode ossicles, mastoid process, petrous bone, cochlea
33
What is the middle ear?
- Air filled cavity
- Between tympanic membrane and inner ear
- Contains ossicles
34
How are ossicles connected?
- Via synovial joints
35
What is the function of the middle ear?
- Amplifies and relays vibrations from tympanic membrane to oval window of cochlea
- Transmits vibration to waves in a fluid medium
36
What tampers ossicle movement?
- Tensor tympani
- Stapedius
- These muscles contract if excessive vibration due to loud noise
- Protective
- Acoustic reflex
37
What is otosclerosis?
- Ossicles fused at articulations due to abnormal bone growth
- Particularly occurs between base plate of stapes and oval window
- Sound vibrations cannot be transmitted effectively to cochlea
- One of the most common causes of acquired hearing loss in young adults
38
What causes otosclerosis?
- Both genetic and environmental causes
- Exact cause unknown
39
How does otosclerosis present?
- With gradual unilateral or bilateral conductive hearing loss
40
What controls the pressure of the middle ear?
- Mucous membrane of middle ear continuously reabsorbs air in middle ear causing negative pressure
- Eustachian tube allows equilibration of pressure within middle ear cavity with atmospheric pressure
- Also allows ventilation and drainage of mucus from middle ear
41
What is otitis media with effusion (glue ear)?
- Not an infection
- Due to Eustachian tube dysfunction
- Fluid and negative pressure in middle ear
- Decreases mobility of tympanic membrane and ossicles
- Hearing affected
42
How is otitis media with effusion treated?
- Most resolve spontaneously in 2-3 months
- If it affects speech and language development or school performance, grommets are used
43
What is acute otitis media?
- Acute middle ear infection
- More common in infants/children
- Mostly viral aetiology
44
What are the signs and symptoms of acute otitis media?
- Otalgia (infants may pull/tug on the ear)
- Other non-specific symptoms e.g. temperature
- Red bulging tympanic membrane
- Loss of normal landmarks
45
What bacteria can cause acute otitis media?
- Streptococcus pneumoniae
- Haemophilus influenzae
46
Why are children more susceptible to getting acute otitis media?
- Eustachian tube is shorter and more horizontal in infants
- Easier passage for infection from nasopharynx to middle ear
- Tube can block more easily e.g. due to adenoid enlargement in children
- Compromises ventilation and drainage of middle ear
47
What are the complications of acute otitis media?
- Tympanic membrane perforation
- Facial nerve involvement
- Mastoiditis (rare but potentially life-threatening)
- Intracranial complications (meningitis, sigmoid sinus thrombosis, brain abscess)
48
What is mastoiditis?
- Middle ear cavity communicates with mastoid air cells via mastoid antrum
- Middle ear infections can spread into mastoid bone via this route leading to mastoiditis
- Swollen area seen behind ear
- Ear turns forward
49
Which parts of the brain can be affected by ear infection?
- Temporal lobe
- Meninges
50
What structures are found within the inner ear?
- Cochlea
- Vestibular apparatus
51
What is the function of the cochlea?
- Fluid movement is generated by footplate of stapes
- Converted into action potentials in CN VIII
- Perceived as sound at temporal lobe
52
What is the function of the vestibular apparatus?
- Fluid movement is generated by position and rotation of head
- Converted into action potentials in CN VIII
-Perceived as position sense and balance
53
How does inner ear pathology present?
- Sensorineural hearing loss
- tinnitus
- Disturbances in balance and vertigo
54
What is the cochlea?
- Fluid filled tube
- Specialised hair cells generate action potentials when moved
55
Where are the specialised cilia of the cochlea found?
- Organ of corti
56
Outline how we hear
1. Auricle and external auditory canal focuses and funnels sound waves towards tympanic membrane
2. Membrane vibrates
3. Vibration od stapes at oval window sets up vibrations/movement in cochlear fluid
4. Sensed by stereocilia in cochlear duct
5. Movement of stereocilia in organ of Corti trigger APs in cochlear part of CN VIII
6. Primary auditory cortex
57
What is the vestibular apparatus?
- Fluid-filled tubes with specialised hair cells (stereocilia) that generate action potentials
- Includes semi-circular ducts, saccule, and utricle
58
How does vestibular apparatus allow us to perceive and maintain our sense of balance?
- Moving position pr rotation of head moves fluid
- Stereocilia bend
- Action potentials generated via CN VIII
- Brain perceive signals as sense of balance
59
What is presbycusis?
- Sensorineural hearing loss associated with old age
- Bilateral
- Gradual
- Corrected with hearing aids
60
What is benign proximal positional vertigo?
- Vertigo only
- Short-lived episodes
- Triggered by movement of head
- Caused by crystals forming in vestibular apparatus - when these dislodge they cause movement of fluid in canals
- Dix-Hallpike manoeuvre (diagnosis)
- Epley manoeuvre (treatment)
61
What is Meniere's disease?
- Vertigo, hearing loss and tinnitus (typically unilateral)
- May also describe 'aural fullness', and nausea and vomiting
- Symptoms longer lasting (30 mins up to 24 hrs)
- Recovery in between recurrent episodes
- Hearing may deteriorate over time and dip during episodes
62
Compare acute labyrinthitis and acute vestibular neuronitis
- History of URTI
- Acute labyrinthitis involves all inner ear structures and is associated with hearing loss, tinnitus, vomiting and vertigo
- Acute vestibular neuronitis usually causes no hearing disturbance or tinnitus
- Sudden onset of vomiting and severe vertigo (lasting several days)
63
What is a gross hearing assessment?
- Whispering a word or number
- Patient repeats it back
- Ear not being tested is masked
64
Which tuning fork tests are used to test hearing?
- Weber's and Rinne's test
- Determines if hearing loss is sensorineural or conductive
65
What is conductive hearing loss?
- Pathology involving external or middle ear
E.g.
- wax
- acute otitis media
- otitis media with effusion
- otosclerosis
66
What is sensorineural hearing loss?
- Pathology involving inner ear structures or CN VIII
E.g.
- Presbycusis
- Noise-related hearing loss
- Meniere's disease
- Ototoxic medications (furosemide, gentamycin, vancomycin)
- Acoustic neuroma
