Lecture 9: Pathology of Pulmonary Infection

Question 1

Five ways the defense mechanisms of the lung could be damaged (predisposing infection)

Answer 1

Decreased cough, injury to mucociliary apparatus, interference with macrophages, pulmonary congestion, secretion accumulation

Question 2

Two patterns of bacterial pneumonia

Answer 2

Bronchopneumonia (patchy, neutrophils, surrounds airways) vs Lobar (less common)

Question 3

T/F: Any organism that can cause broncho can cause lobar pneumonia

Answer 3

True

Question 4

Two most common bacterial causes of pneumona

Answer 4

Step pneumoniae, staph aureus

Question 5

Pseudomonas is associated with what disease? Where do we see this infection histologically?

Answer 5

Cystic fibrosis; tend to center around blood vessels

Question 6

Primary characteristic of bacterial pneumonia

Answer 6

Neutrophils in alveolar spaces

Question 7

Who is at risk for community-acquired acute pneumonia?

Answer 7

Extremes of age, chronic disease, immune def, splenic problems

Question 8

Community acquired bacterial pneumonia pathogens (5)

Answer 8

Strep pneumoniae, staph aureus, haemophilus influenzae, klebsiella, legionalla

Question 9

Four risk factors for acquiring a nosocomial pneumonia

Answer 9

Severe disease, immunosuppression, prolonged antibiotic therapy, invasive devices (catheter/ventilator)

Question 10

Nosocomial bacterial pneumonia pathogens (4)

Answer 10

Pseudomonas, staph aureus (MRSA), e coli, enterobacter

Question 11

Outcomes of pneumonia (6)

Answer 11

Resolution, pleural effusion, empyema (pus in pleural space), fibrosis, abscess, bacteremia

Question 12

Where is aspiration induced abscesses more common?

Answer 12

Right lung

Question 13

Symptoms of lung abscess (5)

Answer 13

Cough, fever, foul-smelling sputum, chest pain, weight loss

Question 14

Treatment of abscess

Answer 14

Antibiotics, but may require surgery

Question 15

Gross features of lung abscess

Answer 15

Thick fibrotic wall surrounding lung pus

Question 16

Microscopic features of lung abscess

Answer 16

Sea of neutrophils

Question 17

What does atypical pneumonia mean?

Answer 17

Inflammation is alveolar septa and pulmonary interstitium (NOT in alveolar space)

Question 18

What are the most common two causes of atypical pneumonia? Where in the community do we find atypical pneumonias?

Answer 18

Mycoplasm or viruses; schools/military camps

Question 19

What is the atypical infiltrate?

Answer 19

Mononuclear inflammatory cells (lymphocytes)

Question 20

Common pulmonary viruses (4)

Answer 20

Cytomegalovirus, herpes, adenovirus, influenza

Question 21

CMV looks like…

Answer 21

Typically involves type 2 pneumocytes; intranuclear inclusions and cytoplasmic inclusions within megalocells

Question 22

Herpes looks like…

Answer 22

Multinucleated together with intranuclear inclusions

Question 23

Adenovirus looks like…

Answer 23

Slightly enlarged cells with a basophilic, large intranuclear inclusion

Question 24

Primary TB infection is characterized by

Answer 24

Necrotizing granulomas

Question 25

Define Gohn complex

Answer 25

Pulmonary granuloma + hilar lymph nodes

Question 26

Secondary TB (often) involves...

Answer 26

Lung apex

Question 27

Miliary TB involves...

Answer 27

Disseminated disease: granulomas all over the place (can be primary or secondary)

Question 28

Histological appearance of necrotizing granulomas

Answer 28

Giant cells/lymphocytes surround necrotizing center, neutrophils outside of this

Question 29

Mycobacteria (stain)

Answer 29

Acid-fast organisms --> stain red

Question 30

Mycobacterium avium occurs in which two situations

Answer 30

1. HIV/Immunocompromised with granulomas or mycobacterial pseudotumor; 2. Right middle lobe syndrome in small, old ladies, bronchiectasis of right middle lobe secondary to poor clearance of secretions

Question 31

Describe histoplasma identification. What does histo look like grossly?

Answer 31

Small, unequal budding (bowling pins), silver stain; necrotizing granuloma similar to TB

Question 32

Coccidiodomycosis identification

Answer 32

Large organisms with thick walled spherules, silver/PAS/H&E staining

Question 33

Blastomycosis identification. Special clinical presentation? Special histological presentation?

Answer 33

Single based broad bud; presents w/ skin disease; large granulomas with necrosis that contains neutrophils

Question 34

Aspergillus identification

Answer 34

Hyphae, narrow angle branching, septate; large organism

Question 35

Invasive aspergillus looks like what?

Answer 35

Bulls-eye parttern (target lesion)

Question 36

T/F: Cryptococcus can occur in healthy people

Answer 36

True

Question 37

What other presentation do we worry about with crypto?

Answer 37

Meningitis

Question 38

Cryptococcus identification

Answer 38

Halo due to mucoid capsule: stain w/ mucoid stains (can also use silver stain), narrow-base buddings

Question 39

Pneumocystis identification (hint: what does it do to the alveolar spaces?)

Answer 39

Fills alvealor spaces with pink, foamy material and must use silver stain; dense rim w/ dot in middle and DO NOT BUD