This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Gynaecology & Obstetrics
Which of the following would most likely be observed in the lung during an autopsy of a 2 week old infant who died of neonatal respiratory distress syndrome? 
Select and explain. 
A. Alveoli filled with neutrophils, B. Dense fibrosis of the alveolar walls, C. Enlarged air space, D. Hyaline membranes and collapsed alveoli
D: Hyaline membranes and collapsed alveoli
Answer: D: Hyaline membranes and collapsed alveoli 
Explanation: Neonatal respiratory distress syndrome is a disease of immaturity. The immature lung is not able to produce sufficient surfactant to prevent collapse of many alveoli. Severe diffuse damage to alveoli causes precipitation of protein ("hyaline membranes") adjacent to many alveolar walls. In infants that survive, paicularly if oxygen was used for therapy, the lungs eventually become heavily fibrotic (misnamed bronchopulmonary dysplasia). Abundant neutrophils would not be seen unless the patient had also developed pneumonia. Fibrosis is a late, not early, feature of respiratory distress syndrome. The air spaces are collapsed, not enlarged, in this condition. Ref: Cunningham F.G., Leveno K.J., Bloom S.L., Hauth J.C., Rouse D.J., Spong C.Y. (2010). Chapter 29. Diseases and Injuries of the Fetus and Newborn. In F.G. Cunningham, K.J. Leveno, S.L. Bloom, J.C. Hauth, D.J. Rouse, C.Y. Spong (Eds), Williams Obstetrics, 23e.