True about Hyaline membrane disease:
**Core Concept**
Hyaline membrane disease, also known as respiratory distress syndrome (RDS), is a condition primarily affecting premature infants. It is caused by a deficiency of surfactant, a substance that reduces surface tension in the lungs, leading to difficulty in breathing and lung expansion.
**Why the Correct Answer is Right**
Surfactant deficiency in hyaline membrane disease disrupts the normal functioning of the lungs, causing alveoli to collapse and leading to respiratory distress. This is because the surfactant, mainly produced by type II pneumocytes, reduces the surface tension at the air-liquid interface within the alveoli, allowing for easier lung expansion during inspiration. Without sufficient surfactant, the alveoli tend to collapse during expiration, making it difficult for the infant to breathe.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hyaline membrane disease is not primarily caused by an infection. While infections can exacerbate the condition, the underlying cause is a deficiency of surfactant.
**Option B:** This option is incorrect because hyaline membrane disease is not due to a problem with the heart. Although infants with RDS may have associated cardiac issues, the primary cause is surfactant deficiency.
**Clinical Pearl / High-Yield Fact**
Infants with hyaline membrane disease are often treated with surfactant replacement therapy, which can significantly improve their lung function and survival rates. It is essential to identify these infants early and provide prompt treatment to prevent long-term respiratory complications.
**Correct Answer:** A.