Ear Flashcards

1
Q

Draw the structure of the ear?

Describe how a sound is heard.

A

Find picture on google

  1. Sound waves directed into ear canal by pinna
  2. Sound wave hits eardrum and vibrates it
  3. The eardrum attaches to malleus, which attaches to incus, which attaches to stapes. There is chain reaction of vibration through the bones
  4. The stapes is connected to the cochlea, it has a piston effect which passes on the vibration to the fluid in the cochlea
  5. The fluid vibrating sends a signal to the brain via nerve VIII
  6. Signal is processed by the brain
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2
Q

What are the bones of the ear? Which order are they in?

A

From outside going in:
Malleus
Incus
Stapes

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3
Q

Where are the cut offs between outer, middle and inner ear?

A

Outer: up to eardrum

Middle: inside of eardrum up to cochlea

Inner: the rest!

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4
Q

What is the eustachean tube?

What is its purpose?

A

Tube that goes from the middle ear to nasopharynx

Equalises pressure of middle ear to that of external auditory meatus

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5
Q

How do we balance?

A

The semi-circular canals

They are attached to the cochlea

They contain endolymph. Upon movement of the head the flow changes speed or direction.

Sensory receptors send signals to the brain

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6
Q

Which nerves pass through the inner ear?

A

VIII - vestibulocochlear, which innervates cochlea and vestibular apparatus

VII - facial, does not innervate anything in inner ear

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7
Q

Draw and label the structures of the pinna?

A

http://teachmeanatomy.info/head/organs/ear/external-ear/

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8
Q

What are some causes of a painful ear?

A

50% is referred pain from jaw, throat, teeth

Other causes:
Otitis externa
Otitis media
Furunculosis
Temporomandibular joint dysfunction
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9
Q

What is otitis externa?

Pathophysiology

A

Inflammation of the external ear (external auditory meatus, auditory canal, outer surface of eardrum)

Caused by infection

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10
Q

Causes of otitis externa?

A

Infection: S aureus, P aeruginosa, H zoster

Skin condition: acne, psoriasis, eczema

Irritants: swimming pool water, trauma (foreign body)

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11
Q

Presentation of otitis externa?

A

Erythema, oedema in ear canal

Exudate

Pain moving tragus or auricle

Pre-auricular lymphadenopathy

Hearing loss

Fever

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12
Q

What is the other name for swimmer’s ear?

A

Acute diffuse otitis externa

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13
Q

What is a furuncle?

A

A small localised infection arising from a hair follicle in the canal

S. aureus

Very painful

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14
Q

What is a serious complication of otitis externa?

A

Necrotising (malignant) otitis externa

Extension of infection into the mastoid and temporal bones

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15
Q

Necrotising (malignant) otitis externa.

Pathophysiology
Presentation
Causative bugs
Risk factors

A

Extension of infection from otitis externa into the mastoid and temporal bones resulting in osteomyelitis

S. aureus
P. aeruginosa

Pain
Oedema
Exudate
Facial nerve palsy

Diabetes, immunocompromise

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16
Q

Investigations of otitis externa?

A

Look for exudate in canal

Look for perforated tympanic membrane

Swab

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17
Q

If you can’t see the eardrum how can you tell if its perforated?

A

They can taste medication placed in ear

They can bow air out of ear when nose pinched

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18
Q

Management of acute otitis externa?

A

Topical drops: antibiotic + steroid

Can use wicks

Remove debris

If cellultitis or lymphadenopathy treat with oral abx

If systemically unwell need an ENT review and possible IV abx

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19
Q

In chronic otitis externa, what things could be perpetuating the problem?

A

Scratching ear
Swimming
Poor compliance with treatment
Skin disease

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20
Q

What do the topical drops used to treat otitis externa contain?

A

Antibiotic: gentamicin, ciprofloxacin
Steroid: dexamethasone or hydrocortisone

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21
Q

What are some causes of discharging ear?

A

Otitis media
Otitis externa
Glue ear
Cholesteatoma

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22
Q

What is otitis media?

Types?

A

Inflammation / infection of the middle ear

Types:

  • AOM: acute otitis media
  • OME: otitis media with effusion (glue ear)
  • COM: chronic otitis media
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23
Q

Risk factors for acute otitis media?

A

Younger age: because eustachian tube is at a less acute angle so material is transmitted through it to middle ear easier

Contact with infections (nursery, daycare, school)

Craniofacial abnormalities

Smoking in household

Dummy use

24
Q

Clinical features of acute otitis media?

What would you see OE?

A
Pain, pulling at ear
Maliase
Irritability crying
Fever
Coryza
Vomiting

Tympanic membrane appears:
Red, yellow or cloudy
Bulging
Air-fluid level

After perforation:
Pain is much less
Discharge in auditory canal

25
Q

Investigations of acute otitis media?

A

No investigation needed

Can do culture of ear discharge
Audiometry if there’s chronic hearing loss

CT or MRI if concerned about complications

26
Q

Management of acute otitis media?

A

Consider admission if:

  • systemic unwell
  • very young
  • suspected acute complications

Treat symptoms: paracetamol, NSAIDs

No antibiotics unless systemically unwell

27
Q

What bugs cause otitis media?

A

H influenzae
S pnuemoniae
M catarrhalis
S pyogenes

28
Q

Complications of acute otitis media?

A

Progression to chronic suppurative otitis media

Labyrinthitis
Meningitis
Intracranial sepsis
Facial palsy
Abscess
Sepsis
29
Q

What is chronic suppurative otitis media?

Pathophysiology

A

Chronic inflammation of middle ear

Ongoing cycle of inflammation, ulceration, infection, granulation of middle ear

Which over time damages nearby structures

30
Q

Risk factors for chronic suppurative otitis media?

A

Multiple episodes of acute otitis media

Lots of contact with infections: Living in crowded conditions, nursery, daycare

Craniofacial abnormalities

31
Q

Clinical features of chronic suppurative otitis media?

A

Chronically discharging ear (otorrhoea)

Conductive hearing loss in affected ear

No signs of acute infection

Otoscope:

  • granulation tissue in middle ear space
  • discharge clear, serous
32
Q

Chronic suppurative otitis media can be safe or unsafe. What does this mean?

A

Safe: CSOM without cholesteatoma

Unsafe: CSOM with cholesteatoma

33
Q

Investigations of chronic suppurative otitis media?

A

Don’t bother with swab

Audiology would show conductive hearing loss

CT or MRI could show cholesteatoma, malignancy, bone involvement

34
Q

Management of chronic suppurative otitis media?

A

ENT referral: who can remove discharge and fully view the tympanic membrane

Topical antibiotics (but not gentamicin or hydrocortisone)

Surgical: repair TM, treat the cholesteatoma

35
Q

In patients with otitis media, what should you not prescribe?

A

Topical ear drops containing

  • aminoglycosides (gentamicin)
  • hydrocortisone

Because they’re ototoxic, and if the tympanic membrane is perforated the drops will get into middle + inner ear

36
Q

Complications of chronic suppurative otitis media?

A

Infection spreading to bone

Labyrinthitis

Facial paralysis

Meningitis, intracranial abscess

Hearing loss

Tympanosclerosis

37
Q

What is the proper name for earwax?

What does it contain?

A

Cerumen

Contains sebum, dead cells, sweat, hair, dust

38
Q

How would you manage impacted cerumen?

A

Ear drops: sodium bicarbonate, olive oil

Irrigation
Microsuction

39
Q

Clinical features of impacted cerumen?

A
Hearing loss
Blocked ears
Tinnitus
Itchiness
Discomfort
40
Q

What are some contra-indications for ear irrigation?

A

Current infection

Perforated TM

Grommets

Otitis media in last 6 weeks

Cleft palate

41
Q

What is ear irrigation?

A

Using water to flush out ear wax

42
Q

What is cholesteatoma?

A

A growth of keratinising squamous epithelium in the middle ear

It is not cancer but it grows independently so is locally invasive

Can erode the ossicles (ear bones), nerves, and sometimes even through base of skull

43
Q

How is cholesteatoma classified? What’s the cause of each?

A

Congenital: occurs during embryogenesis

Primary acquired: eustachian tube defect causing negative middle ear pressure

Secondary acquired: insult to TM, squamous epithelium gets into middle ear and grows there

44
Q

Presentation of cholesteatoma?

A

Progressive conductive hearing loss

Otorrhoea

Signs of infection

As lesion grows and erodes surrounding structures

  • pain
  • vertigo (erosion into inner ear)
  • tinnitus
  • headaches
  • facial nerve palsy
45
Q

How does the cholesteatoma erode into bones?

A

It produces osteolytic enzymes which can erode bone

46
Q

Investigations of cholesteatoma?

A

Otoscopy: can see keratinising lesion, discharge

CT: show extent of lesion and look for bony defects

47
Q

Management of cholesteatoma?

A

Surgical: remove the cholesteatoma

Can manage conservatively if the patient is unfit for surgery, but it will grow and erode things

48
Q

What are the complications of cholesteatoma?

A

Progressive conductive hearing loss

Facial nerve palsy

Infections leading to abscesses

Intracranial complications

49
Q

What types of discharge do these conditions point to?

  • Otitis externa
  • Acute otitis media
  • Chronic otitis media
  • Cholesteatoma
A

Externa: scanty discharge, blood, liquid wax (not mucous)

Acute Otitis media: mucous discharge

Chronic otitis media: Serosanguinous

Cholesteatoma: offensive

50
Q

Pathophysiology of acute otitis media?

A

Infective organisms reach middle ear from nasopharynx via eustachian tube

Often follows a URTI

51
Q

What is glue ear?

What causes it?

A

Another name for otitis media with effusion

Collection of fluid in middle ear cleft
Chronic (not acute) inflammation

Follows acute otitis media
Or eustachian tube defect (blocked, so reduced aeration of middle ear)

52
Q

Clinical features of glue ear?

OE?

A

Hearing loss

  • poor listening
  • poor speech
  • inattention
  • poor progress at school

Often no pain so hard to pick up

Otoscopy: retracted or bulging drum, dull, grey, yellow

53
Q

Investigations of otitis media with effusion?

A

AKA glue ear

Otoscopy

Audiology

Tympanometry: checks mobility of TM

54
Q

Management of otitis media with effusion?

A

Observation

Autoinflation: of the eustachian tube via the nose

Grommets (aka tympanostomy)

Antibiotics, steroids etc are not recommended

55
Q

What is tympanostomy?

A

Grommets

Tiny tubes that go through the TM to ventilate the middle ear

56
Q

Describe audiometry?

A

In a soundproof room
Headphones play sounds at different frequencies
Patient signals / presses button when they hear it
Documents lowest and highest freq sounds they can hear
Also done with bone conduction

57
Q

What is tympanogram?

A

Assess tympanic membranes and bones mobility by changing air pressure in ear canal