WK 9- Ear

Question 1

What is the passage of sound waves through the ear

Answer 1

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

Question 2

What causes acute otitis media

Answer 2

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

Question 3

What age group is AOM most common

Answer 3

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

Question 4

What associated symptoms occur in AOM

Answer 4

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.

Question 5

What would the tympanic membrane look like in AOM

Answer 5

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

Question 6

What complications can arise from AOM

Answer 6

• 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.

Question 7

What is glue ear

-when doe it occur

Answer 7

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

Question 8

What management is required for AOM

Answer 8

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

Question 9

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

Answer 9

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.

Question 10

What is Otitis media with effusion

Answer 10

-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)

Question 11

When does OME occur

Answer 11

following AOM, barotrauma (diving, flying)

Question 12

What symptoms accompany OME

Answer 12

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

Question 13

What is the difference between OME and serous otitis media

Answer 13

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

Question 14

How does OME occur

Answer 14

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

Question 15

What are some predisposing factors to OME;

• enviro
• age
• eustachian tube disruption

Answer 15

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

Question 16

What is the prognosis associated with OME

Answer 16

-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
-

Question 17

How can sensorineural loss result from OME

Answer 17

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.

Question 18

What surgical interventions are available for OME

Answer 18

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

Question 19

What can cause a perforated tympanic

Answer 19

• 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.

Question 20

What is the presentation associated with a perforated TM

Answer 20

• 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

Question 21

What is the tx for a perforated TM

Answer 21

• 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

Question 22

What are the 2 types of hearing loss

Answer 22

Conductive and sensorineural

Question 23

What causes conductive hearing loss

Answer 23

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

Question 24

What causes obstruction of the external auditory canal

Answer 24

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

Question 25

What causes sensorineural loss

Answer 25

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

Question 26

What are the functions of grommets

Answer 26

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)

Question 27

What causes external otitis media (3 main categories)

Answer 27

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

Question 28

What is otitis externa

Answer 28

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

Question 29

How does otitis externa present

Answer 29

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.

Question 30

How can otitis externa be prevented

Answer 30

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)

Question 31

What bacteria most commonly cause otitis externa

Answer 31

pseudomonas aeruginosa, staph aureus

Question 32

What fungi most commonly cause otitis externa

Answer 32

aspergillus, candidiasis

Question 33

What tx is available for otitis externa

Answer 33

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

Question 34

What is the process of a webers test

-what does it test for

Answer 34

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

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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.

Question 37

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

Answer 37

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

Question 38

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

Answer 38

-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)

Question 39

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

Answer 39

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

Question 40

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

Answer 40

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