Transient tachypnea of the newborn is categorized as which type of lung disease?

• A. Obstructive
• B. Restrictive
• C. Infectious
• D. Vascular

Answer: (A)

Transient tachypnea of the newborn results from delayed clearance of fetal lung fluid, which leads to fluid in the airways and mild airway edema. That retained fluid narrows small airways and causes air trapping, producing tachypnea and hyperinflated lungs on imaging. This pattern reflects obstruction to expiratory airflow, which is the hallmark of obstructive processes, more so than a true restrictive pattern (which would show reduced lung volumes from stiffness), an infectious disease (which would center on infection and inflammatory infiltrates), or a vascular problem (which would involve circulation-related edema or shunting rather than primary airway obstruction). TTN typically appears within hours after birth and improves as the fluid is absorbed, with radiographs showing hyperinflation and perihilar markings.