Pneumonia

Question 1

What is pulmonary edema?

Answer 1

Leakage of excessive interstitial fluid, which accumulates in alveolar spaces

Question 2

What can cause pulmonary edema?

Answer 2

• Hemodynamic or cardiogenic pulmonary edema (due to increased hydrostatic pressure)
• Direct increase in capillary permeability (result of microvascular injury)

Question 3

Morphology of pulmonary edema

Answer 3

Gross:

• Lungs are heavy, firm, fluid-filled
• Typically begins basally

Microscopic:

• Engorged capillaries in interstitium
• Granular pink material in alveolar spaces
• Over time:
• hemosiderin-laden macrophages
• fibrosis

Question 4

Acute lung injury

Answer 4

Characterized by abrupt onset of significant hypoxemia and bilateral pulmonary infiltrates in the absence of cardiac failure (noncardiogenic pulmonary edema)

Question 5

Conditions associated with development of ARDS

Answer 5

Sepsis
Diffuse pulmonary infections
Gastric aspiration
Mechanical trauma

Question 6

ALI pathology

Answer 6

-Initiated by injury of pneumocytes and endothelium
-sets in motion a cycle of increasing inflammation and pulmonary damage
components:
-endothelial activation
-adhesion and extravasation of neutrophils (degranulation)
-accumulation of intraalveolar fluid and formation of hyaline membranes (from sloughing of pneumocytes) - damage of type II pneumocytes leads to surfactant abnormalities
-resolution (can lead to fibrosis)