The hyaline membrane in the lung is seen in –
**Core Concept**
The hyaline membrane, also known as the hyaline membrane disease, is a condition characterized by the formation of a protein-rich, fibrin-like membrane on the alveolar surface of the lung. This membrane is composed of fibrin, cellular debris, and surfactant protein. The formation of the hyaline membrane is a result of the disruption of the surfactant system in the lungs.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of the hyaline membrane disease, which is primarily caused by the deficiency of surfactant in the lungs. Surfactant is a complex mixture of phospholipids and proteins that reduces the surface tension of the alveoli, allowing for easier lung expansion during inhalation. In the absence of surfactant, the surface tension increases, leading to the formation of the hyaline membrane. The hyaline membrane disease is commonly seen in premature infants, as their lungs are not yet mature enough to produce sufficient surfactant.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the hyaline membrane is not typically seen in conditions characterized by increased surfactant production.
**Option B:** This option is incorrect because the hyaline membrane is not a characteristic feature of pulmonary edema.
**Option C:** This option is incorrect because the hyaline membrane is not a characteristic feature of pulmonary fibrosis.
**Clinical Pearl / High-Yield Fact**
The hyaline membrane disease is often associated with respiratory distress syndrome (RDS) in premature infants, which is a leading cause of morbidity and mortality in this population. Early recognition and treatment of RDS with surfactant replacement therapy have significantly improved outcomes for affected infants.
**Correct Answer: B. Respiratory Distress Syndrome (RDS)**