Ear Infections

Question 0

What is the pathogenesis of AOM?

Answer 0

URI or allergy causes congestion of mucosa

Narrowing or obstruction of tubes prevents drainage

Question 1

What is otitis media with effusion?

Answer 1

Build up of fluid in the Eustachian tube

No infection
Associated with URI
Cigarette smoke
Allergies
Resolve of it own

Question 2

What can enlarged adenoids cause?

Answer 2

Acute otitis media

Question 3

Why are ear infections more common in children!

Answer 3

Eustation tubes are more narrow and horizontal

Question 4

What is the most common cause of AOM?

Answer 4

Strep pneumoniae

Question 5

What are the main causes of AOM in order of most common?

Answer 5

Strep pneumonia 
Haemophilus influenza (non typable)
Moraxela catarrhalis
Viral (RSV, rhinovirus)
Idiopathic (16-25%)

Question 6

What is strep pneumonia like?

Answer 6

Gram positive
Diplococcus
Alcoholism, diabetes mellitus, chronic renal disease increase susceptibility

Question 7

What are the strep pneumonia virulence factors?

Answer 7

Resistance to PBP
Capsule
Choline-binding - bind carbs on epithelium
Neuroaminidases - cleave mucins
Pneumolysin - pore forming toxin is released disrupts cilia
- iron acquisition and uptake proteins

Question 8

What are some characteristics of Haemophilus influenza?

Answer 8

Gram neg
Coccobacillus
Biofilms
Facultative anaerobes

Question 9

What bacteria has humans as the only host?

Answer 9

Haemophilus influenza

Question 10

What blood factors are required for growth of Haemophilus influenza?

Answer 10

Hematin (X) and NAD (V)

Both present in chocolate agar

Question 11

What type is most Haemophilus flu is most common in AOM?

Answer 11

Nonencapsulated nontypeable (NTHi)
Colonize nasopharynx

Question 12

What is the cause of resistance in NTHi?

Answer 12

Many express beta lactamases

Throw in a beta lactamase inhibitor

Question 13

What can NTHi cause other than AOM?

Answer 13

Genital track

Conjunctivitis

Question 14

What are some characteristics of Moraxella catarrhalis?

Answer 14

Gram neg
Aerobic
Diplococci 
Oxidase positive
Non motile
Chocolate agar
Pili
Adhere to upper respiratory

Question 15

What percent of M. Catarrhalis produce beta-lactamases?

Answer 15

95%

Question 16

How do you test for the presence of Moraxella catarrhalis?

Answer 16

Hockey puck test - easily slide across agar (not as well attached to agar)
Chocolate agar

Question 17

How do you diagnosis AOM?

Answer 17

Pneumatic otoscope to access tympanic membrane

Tympanometry - detect fluid

If recurrent, culture, gram stain

Question 18

What are some prevention strategies for AOM?

Answer 18

Avoid cigarette smoke
Breast feeding and avoid bottles before bed
Wash hands
Flu vaccine and 13- valent pneumococcal vaccine

Question 19

What would you start 6-24 months empiric treatment for AOM?

Answer 19

Oral amoxicillin

Covers strep and Haemophilus

Question 20

What are some side effects of a broad spec amoxicillin?

Answer 20

Oppertunistic infection

Allergy

Question 21

If you do not improve AOM after 48 hours with amoxicillin what do you switch to?

Answer 21

Amoxicillin + clavulanate

Question 22

What is clavulanate?

Answer 22

A beta lactamase inhibitor

Question 23

How do you treat AOM when the Px has a penicillin allergy?

Answer 23

Azithromycin (macrolide)

Question 24

Why would clavulanate not help a resistant strep AOM?

Answer 24

Because the cause of resistance is a change in the target not expression of a beta lactamase

Question 25

What are some complications of otitis media?

Answer 25

``` Erosion of ossicles Cholesteatoma - cyst of epithelium cells Rupture of ear drum Infection of the mastoid Meningitis Speech delay Hearing loss ```

Question 26

What is swimmers ear?

Answer 26

Otitis externa

Question 27

What are some risk factors for otitis externa?

Answer 27

Diabetes Moisture Foreign bodies Trauma

Question 28

How does cerumen prevent otitis externa?

Answer 28

Lysozyme breaks cells More acidic

Question 29

What species causes and acute localized otitis externa?

Answer 29

Staph

Question 30

What organism causes acute diffuse otitis externa?

Answer 30

Pseudomonas aeroginsoa

Question 31

What organisms cause malignant otitis externa the most?

Answer 31

Pseudomonas aeruginosa

Question 32

What two types of otitis externa does pseudomonas aeruginosa cause?

Answer 32

Acute diffuse Malignant

Question 33

What are some characteristics of acute diffuse otitis externa?

Answer 33

Itches, red, pain

Question 34

What is malignant otitis externa?

Answer 34

Invasion of the adjacent bone and cartilage Can progress to cranial nerve palsy and death More In elderly, immunocompromized and diabetes

Question 35

What are some common causes of fungal otitis externa?

Answer 35

Aspergillus Candida albicans

Question 36

How do you diagnosis otitis externa?

Answer 36

Hard because normal flora KOH for fungal Acetic acid cleansing

Question 37

How do you treat otitis externa?

Answer 37

Neomycin(staph) Polymixin Hydrocortisone NSAIDs Topical antibiotics

Question 38

What releases pneumolysin pore forming toxin?

Answer 38

Strep pneumonia

Question 39

What causes visual field deficit most common in HIV patients?

Answer 39

CMV