Pathology of Pneumonia

Question 1

Generally the types of organisms responsible for
1. Intra alveolar
2. Interstitial
pneumonia

Answer 1

1. Bacterial

2. Viral

Question 2

Pneumonia refers to inflammation of the…

Answer 2

Pulmonary parenchyma

Often associated with consolidation of the lung

Question 3

3 ways to classify pneumonia anatomically

Answer 3

Lobar pneumonia
Bronchopneumonia
Interstitial pneumonia

Question 4

6 predisposing factors for pneumonia

Answer 4

Suppression of cough reflex (anesthesia, coma, etc)
Impaired systemic immunity
Impaired mucociliary apparatus
Impaired alveolar macrophage function
Pulmonary edema
General debility (alcoholism, post-op, malnourishment)

Question 5

Lobar pneumonia

Answer 5

Characterized by an area of uniform consolidation of part of a lobe or entire lobe
Most common type of CAP
Majority due to strep pneumo
Lobar distribution is a function of the virulence of the bacterial organism and vulnerability of the host

Question 6

4 stages of lobar pneumonia

Answer 6

1. Congestion (intra-alveolar fluid, few neutrophils, numerous bacteria)
2. Red hepatization (massive intra-alveolar neutrohils with RBCs and fibrin)
3. Grey hepatization (macrophages replace neutrophils and ingest debris)
4. Resolution (but complications may ensue)

Question 7

Bronchopneumonia

Answer 7

Patchy infective consolidation of the lung in a lobular distribution
Common (esp in hospitalized patients and as a terminal event)
Usually bilateral
Pre-exisiting bronchitis spreads to cause bronchiolitis and extends to adjacent lung parenchyma

Question 8

4 complications of bacterial pneumonia

Answer 8

Bacteria dissemination (bacteremia)
Lung abscess formation (S aureus and anaerobes)
Empyema
Death

Question 9

Lung abscess and 2 common causes

Answer 9

Contains purulent exudate and surrounded by a fibrous wall
Most common cause is aspiration
S aureus and anaerobic bacteria from oropharynx

Question 10

Macroscopic and microscopic appearance of pulmonary TB

Answer 10

Macro: caseation necrosis
Micro: necrotizing granulomatous inflammation

Question 11

Appearance of interstitial pneumonia under a microscope

Answer 11

Thickened alveolar walls

Heavily infiltrated with mononuclear leukocytes (lymphocytes and monocytes) (not PMNs like bacterial pneumonia)

Question 12

5 causes of interstitial pneumonia

Answer 12

Viruses
Rickettsia
Chlamydia
Mycoplasma
Pneumocystis jiroveci (carinii)

Question 13

Fungal appearance in

1. Immunocompromised
2. Immunocompetent

Answer 13

1. Fungal hyphae

2. Fungal spores

Question 14

4 pathologies of fungal pneumonia in immunocompromised

Answer 14

Necrotizing pneumonia
Angioinvasion
Tissue infarction
Systemic dissemination

Question 15

Pneumocystic jiroveci pneumonia

Answer 15

Alveoli are filled with a foamy exudate

Interstitium is thickened and contains a chronic inflammatory cell infiltrate