What condition is characterized by the leakage of plasma or blood into the alveolar space?

• A. Bronchitis
• B. Pulmonary edema
• C. Pneumonia
• D. Interstitial lung disease

Answer: (B)

Pulmonary edema is a condition where excess fluid builds up in the alveolar spaces of the lungs. This fluid can derive from plasma or even blood, particularly in cases of cardiogenic pulmonary edema. When the left ventricle fails, it can lead to increased pressure in the pulmonary circulation, causing plasma to leak into the alveoli, impairing oxygen exchange and resulting in respiratory distress. Inflammatory processes, such as those seen in acute respiratory distress syndrome (ARDS), can also lead to a similar leakage as a result of increased vascular permeability.

In contrast, other conditions like bronchitis primarily cause inflammation of the airways with mucus production but do not involve direct leakage of fluid into the alveoli. Pneumonia is characterized by infection leading to inflammation and consolidation in the lung tissue, not necessarily fluid leakage per se into the alveolar spaces. Interstitial lung disease involves scarring and inflammation of the lung tissue itself rather than fluid accumulation in the alveoli. Thus, pulmonary edema distinctly encapsulates the issue of plasma or blood leaking into the alveolar space.