Describe acute respiratory distress syndrome ARDS.

• A. ARDS is due to an allergic reaction causing airway constriction
• B. ARDS is caused by a single microbial pathogen
• C. ARDS is associated with an inflammatory response leading to diffuse alveolar damage and lung capillary endothelial injury
• D. ARDS is a chronic degenerative lung disease

Answer: (C)

Acute respiratory distress syndrome is driven by a severe inflammatory response in the lungs that injures the alveolar-capillary barrier. This injury leads to diffuse alveolar damage and damage to the lung capillary endothelium, causing leakage of protein-rich fluid into the alveoli (noncardiogenic pulmonary edema). The result is stiff lungs, impaired gas exchange, and marked hypoxemia, often with a rapid onset after a triggering insult. A key feature is the diffuse alveolar damage that can progress to hyaline membranes, reflecting extensive injury to the alveolar walls. ARDS can be triggered by many insults such as sepsis, pneumonia, trauma, or pancreatitis, rather than by a single pathogen, and it is an acute process rather than a chronic degenerative disease. The description in this option most accurately reflects ARDS pathophysiology.