Otitis Media - A.Prun

Question 1

Where are these infections?

Otitis externa
Otitis Media
Labrynthitis

Answer 1

Externa - external ear

Media - Middle Ear

Labrynthitis - Inner ear

Question 2

2 major calssifications of otitis media:

Answer 2

Acute otitis Media
- bac/viral, pain, red ear drum, fever, pus

Otitis Media with Effusion

• fluid build up in Eustachian tube
• no infection in ear
• could be casued by cigarette smoke, allergies, or URI, allergies
• resolves on its own

Question 3

Pathogenesis of acute otitis media:

Answer 3

• URI, allergies cause mucus congestion
• Obstruction of eustachian tubes prevents ventilation and drainage
• Accumulation of secretions in middle and presence of pathogen cause infection

Question 4

Why do 70% of children experience at least 1 episode of otitis media?

Answer 4

Under school-age children have Eustachian tubes that are more narrow and horizontal

Question 5

Otitis media is more common what demographics?

other than age…

Answer 5

Native American/Alaska Native

Males

Question 6

Most common bacterial causes of Otitis media:

Answer 6

Strep pneumoniae (25-50%)
Haemophilus Influenzae (15-30%)
Moraxella Catarrhalis (3-20%)

Question 7

Most common viral infections of Otitis media:

Answer 7

RSV and rhinovirus (5-22%)

Question 8

Strept Pneumoniae -
How is it spread?
What are frequent comorbities?
Prevention?

Answer 8

Spread by contact with secretions

Susceptibility increased with chronic diseases (alcoholism, diabetes, renal disease)

Vaccine covers serotypes most likely to cause meningitis

Question 9

Virulence factors of Strep Pneumoniae?

Resistance?

Answer 9

VIRULENCE:
Capsule- blocks phagocytosis
Choline-binding proteins- bind carbohydrates present on surface of epithelial cells
Neuraminidases- cleave sialic acid in host mucins (muccin is a defense factor)
Autolysin A (LytA)- degrades peptidoglycan and causes α-hemolysis during growth
Pneumolysin- pore forming toxin is released disrupts cilia
Iron acquisition - A (PiaA) and uptake A (PiuA)

RESISTANCE
-changes in the
penicillin binding protein

Question 10

What is the resistance of Haemophilus Influenzae?

Answer 10

Many epxress Beta-lactamase

Question 11

Does the Hib vaccine create resistance for the Hemophilus influenzae usually seen in otitis media?

Answer 11

NO!
The H. Infleunzae usually seen in the nasopharynx is the non-encapsulated, Not-Typable H.I

The Hib vaccine ins for the encapsulated form you usually see in meningitis

Question 12

What are some characteristics of moraxella catarrhalis?

Answer 12

Gram(-) aerobic
Colonize in upper resp tract of infants
Most produce beta-lactamase

Hockey puck test - easily slide across agar (for Identifying the organism)

Question 13

How to diagnose otitis media?

Answer 13

Otoscopy

Tympanometry - detects fluid in middle ear

Can aspirate with tyampanocentesis for gram stain and culture (only if the infection is not responding and you are worried about hearing loss)

Question 14

Treatment for otitis media

Answer 14

6-24 month-old empiric treatment
Amoxicillin provides coverage against, strep pneumoniae and H. Influenzae

Without improvement switch to amoxicillin with Clavulanate

Pain management with acetominophen and ibuprofen

Question 15

What if an infant has otitis media has a sever penicillin allergy?

Answer 15

Treat with Azythromycin

Question 16

What should you worry about with patients who come in with previous infection that they were treated for?

Answer 16

Resistance could be associated with this recurrign infection

Question 17

For which organisms would you expect clavulanate to potentially expand coverage?

A -Moraxella catarrhalis
B -Haemophilus influenzae 
C -Streptococcus pneumoniae
D -A and B 
E -A, B, and C

Answer 17

D
Both Moraxella catarrhalis and Haemophilus influenzae

A and B are known to express beta-lactamases
Becaase calvulinate interferes with beta lactamases so there is higher amounts of amoxicillin

C - Streptococcus pneumo resistance is a change in the penicillin binding protein, so clavulinate wont help

Question 18

Comlpications of otitis media?

Why should we take it seriously?

Answer 18

Conductive hearing loss and delayed speech due to perforation of tympanic membrane and erosion of ossicles

Infection can also spread to mastoid, inner ear, temporal bone, meninges, and brain

Question 19

What is Otitis externa?

Answer 19

Unilateral inflammation of external ear canal
-pain, itching, purulent ear discharge

Maceration, trauma, foreign bodies, excessive moisture are risk factors

Peak in incidecne in summer! (swimming and stuff)

Question 20

What kinds of bugs cause otitis externa? How do they affect the external ear?

Answer 20

Acute localized- most often Staphylococcus pustule or furuncle associated with hair follicles

Acute diffuse- Pseudomonas aeroginosa - itches, red canal, and painful

Malignant- Pseudomonas aeroginosa, invasion of adjacent bone and cartilage which can progress to cranial nerve palsy and death.
More common in elderly, poorly controlled diabetes, and immunocompromised.

Fungal- Aspergillus and Candida

Question 21

Staph Aureus virulence factors:

Answer 21

Capsule and protein A - Bind Fc protion of IgG to stop phagocytosis

Coagulase - cause fibrin polymerization and clotting

Membrane toxins - Hemolysin and leukotoxin

Question 22

Management of otitis externa?

Answer 22

Topical antibiotics usually sufficient

Neomycin + Polymyxin + Hydrocortisone

Question 23

What infection presents with red eye, mild cold, and clear drainage?

Answer 23

Adenovirus

Question 24

What infection releases pneumolysin pore-forming toxin?

Answer 24

Strep Pneumo!

Question 25

What infection presents with visual field deficits and is common in HIV-infected individuals?

Answer 25

Cytomegalovirus

Question 26

What infection releases releases green-yellow discharge from the eyes?

Answer 26

Neisseria Gonorrhea!