Pulmonary Infections (Path)

Question 1

Classification of Pneumonias

Answer 1

(1) Community Acquired Pneumonias - bacterial, viral, etc
(a) Typical - Gm+/– bacteria
- -> lobar or broncho-pneumonia
(b) Atypical - viruses, other bacteria, fungi
- -> interstitial pneumonia
(2) Aspiration Pneumonias - anaerobic bacteria
(3) Nosocomial Pneumonias - various

Question 2

impaired defenses leading to pneumonia

Answer 2

(1) ↓ cough reflex -> aspiration
(2) injury to mucociliary escalator (smoking, viral infection, genetic defects)
(3) secretions (cystic fibrosis, chronic bronchitis)
(4) edema/congestion (CHF)
(5) ↓ macrophage function (smoking, O2 toxicity)

Question 3

community-acquired acute pneumonias

Answer 3

“Typical”

bacterial or viral; increased risk in v. young, elderly, chronic disease (COPD), immune deficiencies, lack of splenic function

Question 4

morphology of lobar pneumonia

Answer 4

alveolar sacs fill w/ neutrophils, pink exudate

1. congestion
2. red hepatization - neuts + RBCs
3. grey hepatization - RBC death
4. resolution - Type II = stem cells

Question 5

morphology of bronchopneumonia

Answer 5

acute neutrophilic suppurative exudation filling bronchi, bronchioles, alveoli that eventally resolves; involvement of pleura (pleuritis) can result in fibrous thickening or adhesions

Question 6

causes of lobar pneumonia

Answer 6

Streptococcus pneumoniae

Klebsiella pnemoniae

Question 7

causes of bronchopneumonia

Answer 7

Staphylococcus aureus
Haemophilus influenzae type b
Pseudomonas aeruginosa
Legionella pneumophila
Moraxella catarrhalis

Question 8

Gm+ causes of pneumonia

Answer 8

diplococci, catalase negative - Streptococcus pneumoniae

cocci clusters, catalase pos - Staphylococcus aureus

Question 9

most common cause of community acquired pneumonia

Answer 9

Streptococcus pneumoniae

Question 10

diabetics, alcoholics

Answer 10

Klebsiella pneumoniae (aspirated Gm– enteric flora)

Question 11

most common secondary to viral infection or chronic lung disease

Answer 11

Staphylococcus aureus

Question 12

IV drug users

Answer 12

Staphylococcus aureus

Question 13

common in children and adults w/ COPD

Answer 13

Haemophilus influenzae (type b)
causes meningitis, epiglottitis in kids

Question 14

common nosocomial, immunocompromised, cystic fibrosis

Answer 14

Pseudomonas aeruginosa

Question 15

more severe in immunocompromised

transmitted via water source and aerosolization

Answer 15

Legionella pneumophila

Question 16

common in elderly and patients w/ COPD

pediatric otitis media

Answer 16

Moraxella catarrhalis

Question 17

Community-Acquired Atypical/”Walking” Pneumonias

Answer 17

viral or non-viral organisms (mycoplasma, chlamydia)

ranges from mild URIs to severe LRIs

Question 18

morphology of atypical/interstitial pneumonia

Answer 18

diffuse interstitial infiltrates WITHOUT CONSOLIDATION

Question 19

Streptococcus pneumoniae

Answer 19

(community-acquired typical pneumonia, lobar)
Gm+ diplococci
most common cause (adults, elderly)
-> empyema

Question 20

Klebsiella pneumoniae

Answer 20

(community-acquired typical pneumonia, lobar)
Gm– rod
diabetic and alcoholics
aspirated Gm– enteric flora
mucoid capsule; gelatinous red-current jelly sputum
-> abscess

Question 21

Staphylococcus aureus

Answer 21

(community-acquired typical pneumonia, broncho-)
Gm+ cocci clusters
most common 2ary (influenza, viral pneumonias)
IV drug users are at risk (+ endocarditis)
also elderly, hospitalized, chronic lung disease
-> abcess or empyema; hematogenous spread - endocarditis, brain and kidney abscesses

Question 22

Haemophilus influenzae (type b)

Answer 22

(community-acquired typical pneumonia, broncho-)
Gm– coccobacillus; culture hematin/NAD+
common in children (causes meningitis, epiglottitis)
adults w/ COPD

Question 23

Pseudomonas aeruginosa

Answer 23

(community-acquired typical pneumonia, broncho-)
Gm– rod; culture blue/green
nosocomial, immunocompromised, cystic fibrosis
focal hemorrhage and necrosis

Question 24

Legionella pneumophila

Answer 24

(community-acquired typical pneumonia, broncho-)
Gm– coccobacillus; charcoal yeast + iron; stains poorly
immunocompromised
transmitted via water soure and aerosolization
*can also be categorized as an atypical pneumonia

Question 25

Moraxella catarrhalis

Answer 25

(community-acquired typical pneumonia, broncho-)
Gm– diplococcus
common in elderly and patient w/ COPD
pediatric otitis media