Upper Respiratory Tract Infections 2: The Ear

Question 1

What is otitis externa?

Answer 1

Infection of the external auditory canal

Swimmer’s Ear

Question 2

What causes otitis externa?

Answer 2

Fluid and foreign bodies cause irritation and maceration
OR
Absorption of moisture leading to maceration, inflammation and suppuration

Question 3

What are the common causative agents in otitis externa?

Answer 3

Normal skin flora and gram-negative bacilli (particularly Pseudomonas Aeruginosa)

Question 4

What is often the causative agent in swimmer’s ear and why?

Answer 4

Pseudomonas Aeruginosa - likes moisture

Question 5

How it otitis externa managed?

Answer 5

Management depends on underlying cause and clinical presentation

Question 6

Otitis externa: what should be done along with giving ear drops (when indicated)?

Answer 6

Can put alcohol in the ear to dry it out and then give drops

Question 7

What is the presentation of otitis externa?

Answer 7

Variable presentation and severity:

• oedema, erythema, ?pus
• itching and pain
• invasive / malignant = serious presentation

Question 8

What is invasive / malignant otitis externa?

Answer 8

Nectrotizing infection spreading to surrounding soft tissue, blood vessels, cartilage and bone; life-threatening intracranial infection can result
(usually only seen in immune compromised patients)

Question 9

How is acute otitis media defined?

Answer 9

Defined by the presence of fluid in the middle ear accompanied by signs and symptoms of acute illness

Question 10

What are some of the signs and symptoms of acute otitis media?

Answer 10

• ear pain
• examination of the ear drum may show redness, bulging and pus behind the drum
• fever, headache, lethargy or irritability

Question 11

How common is acute otitis media?

Answer 11

Very common

- by 3 years of age, ⅔ of children have had at least one episode

Question 12

What is the most common bacterial agent in acute otitis media?

Answer 12

S. Pneumoniae

Question 13

What are the aetiological agents of acute otitis media?

Answer 13

1. Bacterial: S. Pneumonia, H. Influenzae, Morazella Catarrhalis, S. Pyogenes
2. Viral (25%): RSV, Influenza Virus, Rhinovirus
3. May have a mixed viral-bacterial infection

Question 14

What is the pathogenesis of acute otitis media?

Answer 14

• middle ear is part of a continuous system that includes the nares, nasopharynx, ET medially and anteriorly, and mastoid cells posteriorly
• lined with respiratory epithelium that contains ciliated cells, mucus-secreting goblet cells, and cells capable of secreting local immunoglobulins
• congestion of mucosa of the ET = obstruction
• secretions that are constantly formed by the mucosa of the middle ear accumulate behind the obstruction
• in the presence of a bacterial pathogen, a suppurative otitis media develops

Question 15

What is the management of acute otitis media?

Answer 15

Drug of choice AMOXICILLIN
Drug must act against 3 most common aetiologies: S. Pneumonia, H. Influenzae, M. Catarrhalis
HIGH DOSE given: 90mg/kg/day

Question 16

Following administration of the correct pharmaceutical agent, how quickly should acute otitis media improve?

Answer 16

Usually within 48-72 hours

Question 17

What are some of the causes of no response to therapy in acute otitis media?

Answer 17

• may be due to resistance by beta-lactamase producing H. Influenzae / M. Catarrhalis or Penicillin resistant S. Pneumoniae

Question 18

What should be done if there is no response to therapy in acute otitis media?

Answer 18

Consider referral to ENT specialist for tympanocentesis and middle ear fluid culture.

Question 19

What drugs should be used for acute otitis media if initial therapy fails?

Answer 19

• Amoxicillin-Clavulanate

- Ceftriaxone

Question 20

What is the mastoid?

Answer 20

Mastoid is a bone with air-filled spaces, and communicates with the middle ear

Question 21

What is a severe complication that can follow a middle ear infection?

Answer 21

Infection of the mastoid (mastoiditis) can follow middle ear infection.

Question 22

What is mastoiditis?

Answer 22

Infection of the mastoid:

• purulent exudate followed by bone necrosis and abscess cavities
• swelling, redness and tenderness over the mastoid bone
• extension to contiguous structures can lead to serious complications

Question 23

How should mastoiditis be managed?

Answer 23

1. Culture of middle ear drainage
2. Systemic antimicrobials
   (may also need to go to theatre for drainage)