Hyaline membranes are most associated with which condition?

• A. Acute respiratory distress syndrome
• B. Chronic bronchitis
• C. Atelectasis
• D. Pulmonary embolism

Answer: (A)

Hyaline membranes arise from diffuse alveolar damage as seen in acute respiratory distress syndrome. When the alveolar–capillary barrier is injured, protein-rich edema fluid leaks into the airspaces and mixes with necrotic alveolar epithelial cells. This material lines the alveoli and alveolar ducts as thin, eosinophilic, glassy membranes, impeding gas exchange and contributing to the severe hypoxemia typical of ARDS. The other conditions listed involve airway or vascular pathology but do not characteristically form these hyaline membranes.