What is the primary cause of Respiratory Distress Syndrome (RDS)?

• A. Deficiency of surfactant
• B. Infection
• C. Airway obstruction
• D. Congenital heart defects

Answer: (A)

The primary cause of Respiratory Distress Syndrome (RDS), particularly in preterm infants, is a deficiency of surfactant. Surfactant is a substance produced in the lungs that helps reduce surface tension within the alveoli, preventing their collapse and facilitating gas exchange. In premature infants, the lungs may not be mature enough to produce sufficient amounts of surfactant, which leads to increased surface tension, atelectasis (collapse of the alveoli), and impaired oxygenation. This results in the hallmark symptoms of RDS, including difficulty breathing, cyanosis, and decreased oxygen saturation.

In contrast, while infections, airway obstruction, and congenital heart defects can lead to respiratory distress, they are not the primary cause of RDS. Infections might contribute to respiratory issues in older infants or children, but they are not a typical cause of RDS in the perinatal period. Airway obstruction is usually more acute and is not related to the surfactant deficiency seen in RDS. Congenital heart defects affect circulation rather than the lung's ability to inflate properly due to surfactant issues, thus not being the main factor in RDS.