Loss of pulmonary surfactant in premature infant causes __________
**Core Concept**
Pulmonary surfactant is a complex mixture of phospholipids and proteins that reduces surface tension within the alveoli, facilitating lung expansion and preventing alveolar collapse during expiration. In premature infants, the deficiency of pulmonary surfactant is a critical factor in the development of respiratory distress syndrome (RDS).
**Why the Correct Answer is Right**
The loss of pulmonary surfactant in premature infants leads to an increase in surface tension within the alveoli, causing them to collapse during expiration. This results in a decrease in lung volume and a subsequent increase in the work of breathing, leading to respiratory distress. The alveoli are not able to expand properly, and the lungs become stiff and difficult to inflate. This condition is a major cause of morbidity and mortality in premature infants.
**Why Each Wrong Option is Incorrect**
**Option A:** Hypertension - While hypertension is a concern in premature infants, it is not directly related to the loss of pulmonary surfactant.
**Option B:** Diaphragmatic hernia - Diaphragmatic hernia is a congenital defect that can cause respiratory distress, but it is not caused by the loss of pulmonary surfactant.
**Option C:** Pneumonia - Pneumonia is a bacterial infection of the lung that can cause respiratory distress, but it is not directly related to the loss of pulmonary surfactant.
**Clinical Pearl / High-Yield Fact**
Premature infants with respiratory distress syndrome (RDS) require exogenous surfactant replacement therapy to reduce surface tension and improve lung compliance.
**Correct Answer: C. Respiratory distress syndrome (RDS).**