A neonate born at 32 weeks gestation develops worsening respiratory distress within 2 hours of birth. CXR shows a ground-glass appearance with air bronchograms. Which of the following is the MOST accurate statement regarding the pathophysiology of this condition?

• A Surfactant deficiency increases alveolar surface tension leading to alveolar overdistension
• B Reduced surfactant causes increased pulmonary blood flow from left-to-right shunting
• C Immature type I pneumocytes fail to produce adequate amounts of protein B surfactant
• D Surfactant deficiency leads to reduced alveolar surface tension causing alveolar collapse at end-expiration ✓

Explanation

In respiratory distress syndrome (RDS/HMD), surfactant deficiency increases alveolar surface tension (not reduces it), causing alveolar collapse at end-expiration and reducing functional residual capacity. Type II pneumocytes (not type I) produce surfactant; SP-B is one component. The ground-glass appearance with air bronchograms is the classic radiological finding. The other options contain inaccuracies: surface tension is increased (not decreased), and overdistension does not occur.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.