Which diagnosis is most consistent with a newborn born at 30 weeks gestation presenting with tachypnea and decreased lung expansion?

The diagnosis most consistent with a newborn born at 30 weeks gestation who presents with tachypnea and decreased lung expansion is respiratory distress syndrome (RDS). This condition, also known as hyaline membrane disease, is primarily caused by a deficiency of surfactant, which is critical for reducing surface tension in the alveoli and preventing their collapse. In preterm infants, especially those born before 34 weeks of gestation, the lungs are often not mature enough to produce sufficient surfactant, leading to the symptoms observed.

The signs of tachypnea, which is rapid breathing, combined with decreased lung expansion, indicates that the lungs are not functioning properly. In RDS, the lack of surfactant leads to atelectasis (collapse of alveoli) and further respiratory distress. The onset of symptoms typically occurs immediately after birth, aligning with the presentation of this newborn.

Although pneumonia, transient tachypnea of the newborn, and congenital diaphragmatic hernia can also cause respiratory distress in neonates, they have other distinguishing features. Pneumonia often presents with fever and signs of infection. Transient tachypnea is more commonly seen in term infants and typically resolves quickly, usually within 24-72 hours of life. Cong