Respiratory Infections

Question 1

name the sterile and non sterile areas of the respiratory tract ?

how does infection occur?

what are some Mechanisms of Defense by the respiratory Tract ?

Answer 1

• Upper: nares to pharynx - colonized with bacteria

	* Lower: Trachea to alveoli - normally sterile
	* Associated structures - normally sterile
		* Paranasal sinuses
		* Middle ear
	* Infections occur when sterile areas become colonized by growth of bacteria

	* Nares- filtration 
	* Epiglottic Reflex -- prevents aspiration 
	* Cough 
	* Mucus secreting and ciliated cells entrap and expel particles 
	* Aleveolar macrophages 
	* Immune response (antibodies, complement) 
	* Lymphatic drainage of the lung

Question 2

Name the infections of the respiratory tract?

Answer 2

Otitis Media
Sinusitis
Pharyngitis
Pneumonia

Question 3

• Differentiate between Acute Otitis Media and Otits Media with Effusion

Answer 3

• Effusion will persist following an AOM (active infection) for several weeks

Use Pneumoatic Otoscopy
AOM - bulging TM, no cone of light, filled with pus,
More stiff upon pneumatic otoscopy

OME - not bulging out; TM Is concave; , more mobile TM upon pneumatic otoscopy  filled with fluid (but not pus)

Question 4

What bugs cause AOM?

What is the major complication of AOM?

How is AOM Treated?

Answer 4

S. Pneumoniae – 30 to 40 %
Some resistance due to altered PBP binding site
H. Influenza (nontypeable) – 20 - 30%
Moraxella catarrhalis – 8-18%

Complication: Mastoiditis

Treatment:
Amoxicillin - covers S. pneumo and H flu,
does not cover moraxella

Can use amoxicillin - clavulonate to cover Beta lactamase producing H flu

“wait and see” - for indeterminate cases

Question 5

Sinusitis:

• what is it?
• What are some risk factors?
• How do you differentiate between Sinusitis and the common cold?

Answer 5

Sinusitis: Bacterial infection of the paranasal sinuses

Risk Factors: Obstruction; impeded cilliary function; abnormal mucus production (CF); Immuno deficiency, anatomical breach

• Differentation between SInusits and Cold:
• Cold = Viral infection;
  Rhinorrhea, short lived fever
• Sinusitis: HA + Localizing signs to the sinus area (pain)
  Acute: persistent nasal drainage that does not resolve on its own; +/- fever
  Acute Severe: high grade and persistent fever and purulent nasal drainage

CT/XR: consilidation of the sinuses

Question 6

Bugs that cause sinusitis?

Treatment of Sinusitis?

What are some complications of sinusitis ?

Answer 6

Bugs - S. Pneumo, H. flu, Moraxella

Drugs -spontaenous resolution in 40-60% of cases
Children: Amoxicillin +/- clavulanate
Adults: Same, or Cephalosporin, quinolone

Complications: orbital, periorbial cellulitis;

meningitis, osteomyelitis, cavernous sinus thrombus

Question 7

Pharyngitis:

• clinical manifestations?
• what bug causes it?
• diagnostic tests?
• what drug treats it?
• Complications ?

Answer 7

Clinical: Fever, exudates, cervical LAD, NO COUGH
Maybe a Scarlett Fever Rash

Bug: Strep Pyogenes (group A strep)

Diagnosis: Rapid Strep test; culture

Treatment: PCN, cephalosporins

Complications:
Suppurative - peritonsilar, retropharyngeal abscess

Non suppurative - Rheumatic fever (prevent with early treatment); glomerulonephritis (might not be able to prevent)

Question 8

Bacterial Pneumonia:

• what are the causative bugs?
• What is the typical onset?
• What the CXR look like
• Lab findings?

Answer 8

the bugs: S. Pneumo, H. flu, S. aureus, S. pyogenes

The onset: Acute, sustained fever, plueritic chest pain, purulent cough

General sx: Tachypnea, increased work on breathing, crackles and decreased breath sounds

The CXR: Lobar consolidation, effusion

Diagnosis: Sputum culture

Question 9

Atypical Pneumonia:

• what is this also known as?
• what age group is at risk?
• What are the causative bugs?
• what are some distinct features with each bug?
• What is onset like?
• What does the CXR look like?

Answer 9

• aka “walking pna”
• school children are at risk
• bugs:
  Mycoplasm pnuemoniae: rash, cold agglutins
  Legionella pneumoniae: ICU, extrapulmonary manifestations; sputum with purulence no organsism
  Chlamydia pneumonia:

Onset: Subacute – flu symptoms (myalgia, fatigue, fever, non productive cough) extrapulmonary signs

CXR: diffuse disease/interstitial

Question 10

Severe Pneumonia:
- what can this be preceded by?
- What are the causative bugs?
-

Answer 10

Rapidly progressive

Can be preceded by influenza infection

Bugs: S. pneumo, MRSA, Legionella

Question 11

Treatment regimens:

1) Outpatient at low risk – what bugs?
2) Out patient at high risk or Inpatient – what bugs?
3) ICU patient – what bugs?

Answer 11

1) Azithromycin: covers S pneumo, H flu, mycoplasm

2) Concern for macrolide resistant S. pneumo: therefore use
Azithromycin + Beta Lactam
or Respiratory fluoroquinone (levofloxacin)

3) Concerned for legionella, MRSA and possibly pseudomonas (or other Gram Negatives)
- 3rd Gen Cephalosporins
- Ampicillin/Sulbactam
- Azithromycin
- Levofloxacin
- Consider Vanc
- Consider anti-psueomonal