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Flashcards in WK 9- Ear Deck (40)
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1
Q

What is the passage of sound waves through the ear

A

eardrum→malleus→incus→stapes→ when stapes vibrates it vibrates oval window → these vibrations send waves down the endolypmph in the cochlea → in the cochlea, the vibrations cause movement of the hair cells→ the hair cells are attached to a neuron from the cochlear branch of the vestibulochochlear nerve→ impulses are transmitted from this nerve to the brain

2
Q

What causes acute otitis media

A

streptococcus pneumonia (35%), non-typable strains of haemophilus influenza (25%), Moraxella catarrhalis (15%) and viral infections

3
Q

What age group is AOM most common

A

2/3 of children have at least one episode by age 3, and 90% have at least one episode by school entry.

4
Q

What associated symptoms occur in AOM

A

fever, ear pain (irritability in pre-verbal children), vomiting, lethargy, +/- anorexia
-There may be associated signs of URTI, such as coryza, red tonsillopharynx, cough etc. The features suggest the infection is viral.

5
Q

What would the tympanic membrane look like in AOM

A

The usual middle ear landmarks (handle of malleus, incus, light reflex) are not well seen.

  • The tympanic membrane (TM) is dull and opaque, and may be bulging. The TM colour varies but is characteristically yellow-grey.
  • Movement of TM is reduced
6
Q

What complications can arise from AOM

A
  • Perforation of the TM results in purulent otorrhoea, and usually relief of pain (due to pressure release).
  • Effusion (glue ear)
  • Febrile convulsions are commonly related to AOM.
  • Suppurative complications such as mastoiditis, suppurative labyrinthitis or intracranial infection (meningitis, extradural or subdural abscess, brain abscess) are very uncommon in our population.
  • Other potential complications include facial nerve palsy, lateral sinus thrombosis, and benign intracranial hypertension.
7
Q

What is glue ear

-when doe it occur

A

Serous middle ear effusion commonly persists for several weeks or even months following an episode of AOM→can cause conductive hearing loss → causes developmental delays in those effected

8
Q

What management is required for AOM

A

most cases of AOM in children resolve spontaneously

  • antibiotics provide a small reduction in pain and should really only be used if there is systemic symptoms→ weight the benefits against harms related to the child and population (resistance)
  • can give symptomatic relief via paracetamol or lignocaine drops to the ear drum
9
Q

What other conditions must be considered in AOM of a young child

A

a child with otitis media can also have serious bacterial infection such as septicaemia or meningitis.
-If systemically unwell, consider coexistent causes of sepsis - do not accept otitis media as the sole diagnosis in a sick febrile young child without elimination of a more serious cause.

10
Q

What is Otitis media with effusion

A

-Otitis media with effusion (OME) is characterized by a nonpurulent effusion of the middle ear that may be either mucoid or serous and have impaired hearing (like an echo)

11
Q

When does OME occur

A

following AOM, barotrauma (diving, flying)

12
Q

What symptoms accompany OME

A

involve hearing loss or aural fullness but typically do not involve pain or fever.

13
Q

What is the difference between OME and serous otitis media

A

Serous otitis media is a specific type of otitis media with effusion caused by transudate formation as a result of a rapid decrease in middle ear pressure relative to the atmospheric pressure–> fluid is watery and clear

14
Q

How does OME occur

A

Eustachian tube dysfunction causing inability to drain the middle ear-> can be due to ciliary dysfunction; mucosal edema; hyperviscosity of the effusion; and, possibly, an unfavorable pressure gradient

15
Q

What are some predisposing factors to OME;

  • enviro
  • age
  • eustachian tube disruption
A

Enviro: bottle feeding, feeding while supine, having a sibling with otitis media, attending daycare, being around those who smoke
Age; In infants, the eustachian tube has a nearly horizontal orientation (relative to the ground) and develops the 45° angle (as in adults) and size/shape of the tube make ventilation of the middle ear hard–> as child ages and the eustachian tube straightens, it drains easier–> hence OM with effusion in an adult can indicate a naspharyngeal mass
Eustachian tube; disruptions in eustachian tube opening (commonly occur in pt with cleft palate and in children with Down syndrome), decreased mucociliary clearance and higher viscosity of mucus

16
Q

What is the prognosis associated with OME

A

-leading cause of hearing loss in children
-associated with delayed language development in children younger than 10→ hearing loss is normally conductive loss
-can have sensorineural loss
-

17
Q

How can sensorineural loss result from OME

A

Otitis media with effusion has been associated with sensorineural hearing loss. Both prostaglandins and leukotrienes have been found in high concentrations in middle ear effusions (MEE), and their ability to cross the round window membrane has been demonstrated. Chronic exposure to these metabolites of arachidonic acid may cause a temporary and sometimes permanent sensorineural hearing loss.

18
Q

What surgical interventions are available for OME

A

Insertion of grommets–>
-Surgical intervention significantly improves the clearance of middle ear effusion in this population, but the benefits for speech and language development as well as quality of life remain controversial

19
Q

What can cause a perforated tympanic

A
  • Infections of the middle ear.
  • Direct injury to the ear - for example, a punch to the ear.
  • A sudden loud noise - for example, from a nearby explosion. The shock waves and sudden sound waves can tear (perforate) the eardrum. This is often the most severe type of perforation and can lead to severe hearing loss and ringing in the ears (tinnitus).
  • Barotrauma. This occurs when you suddenly have a change in air pressure. For example, when descending in an aircraft.
  • Poking objects into the ear.
  • Grommets.
20
Q

What is the presentation associated with a perforated TM

A
  • symptoms may include audible whistling sounds during sneezing and nose blowing, decreased hearing, and a tendency to infection during colds and when water enters the ear canal.
  • purulent drainage occurs when there is perforation and an infection
21
Q

What is the tx for a perforated TM

A
  • a perforated tympanic membrane will usually heal within 6-8 weeks
  • antibiotics can be used when there is a chance of an infection developing in the middle ear whilst the membrane is healing
  • avoid water entering the ear whilst the ear is healing
  • caution with using ear drops as some may damage the nerve supply to the face
  • surgical treatment is occasionally required to fix the membrane
22
Q

What are the 2 types of hearing loss

A

Conductive and sensorineural

23
Q

What causes conductive hearing loss

A

Can be caused by→ Obstruction of the External Auditory Canal, TM perforation, Middle ear pathology (OM), ossicular pathology

24
Q

What causes obstruction of the external auditory canal

A

caused by poor function or blockage of the Eustachian tube including→ inability of the tiny hairs in the auditory canal to remove fluid, poor squeezing function of the Eustachian tube, narrow Eustachian tube, adenoids tissue blocking Eustachian tube (mainly in children), swollen nasal secretions, tumours

25
Q

What causes sensorineural loss

A

-can be due to familial/congenital conditions, trauma (surgery), toxins (drugs), radiation, infection (meningitis, Zoster, CMV)

26
Q

What are the functions of grommets

A

used to equalise pressure across the tympanic membrane→ used because of build up of fluid in the middle ear→ usually fall out but help to reduce pressure, pain and reduce episodes of otitis media (due to chronic serous effusion)

27
Q

What causes external otitis media (3 main categories)

A
  1. Bacterial infection- most common cause
  2. Fungal infection
  3. Non-infectious dermatological conditions.
    →Psoriasis, Seborrhoeic Dermatitis, Acne, Irritant or Allergic contact Dermatitis e.g. from local irritants, including topical preparations or use of hearing aids or ear plugs
28
Q

What is otitis externa

A

-Otitis externa is an inflammatory condition of the external auditory canal

29
Q

How does otitis externa present

A

It is characterised by redness, swelling, scaling and thickening of the canal skin lining and is accompanied by varying degrees of otalgia (discomfort), itch, deafness and otorrhoea (discharge). The canal swells and becomes occluded.

30
Q

How can otitis externa be prevented

A

Common causes that allow the overgrowth of bacteria in the external ear include: swimming, high humidity (add extra moisture that carry bacteria into the ear wax→ leads to inflammation- avoid this by drying ears, wear a swimming cap, acidifying air drops)

31
Q

What bacteria most commonly cause otitis externa

A

pseudomonas aeruginosa, staph aureus

32
Q

What fungi most commonly cause otitis externa

A

aspergillus, candidiasis

33
Q

What tx is available for otitis externa

A

topical antibiotic/antifungals with steroids to reduce swelling, avoidance of causes, ear wicks

34
Q

What is the process of a webers test

-what does it test for

A

detects unilateral conductive hearing loss and unilateral sensorineural hearing loss
Process:
1. Place a vibrating tuning fork of 512Hz in the middle of the forehead
2. Ask the patient if the sound is heard equal in both ears, or louder in one

35
Q

What result would occur if the pt has conductive hearing loss when testing with the weber test

A

A patient with a unilateral conductive hearing loss would hear the tuning fork loudest in the affected ear.

36
Q

What result would occur if the pt has sensorineural hearing loss when testing with the weber test

A

A patient with a unilateral sensorineural hearing loss would hear the sound louder in the unaffected ear, because the affected ear is less effective at picking up sound even if it is transmitted directly by conduction into the inner ear.

37
Q

What is the process for doing a rinnes test and what does it test for

A

tests for unilateral hearing loss and establishes which ear has the greater bone conduction.
-Combined with the patient’s perceived hearing loss, it can be determined if the cause is sensorineural or conductive
Process:
1. Place a high frequency (512 Hz) vibrating tuning fork against the patient’s mastoid bone
2. Ask the pt to tell you when the sound is no longer heard
3. Once the sound is no longer heard, move the tuning fork next to the patients ear (U facing forward)
4. Ask the pt when they stop hearing the tuning fork

38
Q

What result would occur if the pt had conductive hearing loss when doing a rinnes test

A

-if the pt can hear the mastoid test, but can not hear the tuning fork when it is placed next to the ear, then the pt has conductive hearing loss (the nerve is working as it can pick up conduction through bone, but there is an issue conducting the sound through the canal)

39
Q

What result would occur if the pt had sensorineural hearing losswhen doing a rinnes test

A

if the patient has sensorineural loss, both bone and air conduction is equally diminished, implying they will hear the tuning fork by air conduction after they can no longer hear it through bone conduction→ what differentiates sensorineural loss from normal hearing is that even though the sound will be heard, it will be greatly diminished in time → if you can still hear the fork, then indicates the patients hearing is abnormal

40
Q

What would be the diagnosis if the Rinne test shows that air conduction (AC) is greater than bone conduction (BC) in both ears and the Weber test lateralizes to a particular ear

A

there is sensorineural hearing loss in the opposite (weaker) ear.