Transient Tachypnea of the Newborn

Transient tachypnea of the newborn (TTN), also known as wet lung disease, retained fetal lung liquid, retention of fetal lung fluid, respiratory distress syndrome type II, transient respiratory distress of the newborn, and neonatal retained fluid syndrome, occurs when there is retained fluid in the neonate's lung.

This is a diagnosis of exclusion when no other cause is found for the infant's tachypnea. It is seen in neonates who are sedated or following cesarean section

Radiographs show a normal heart size with findings similar to pulmonary edema: Diffuse, bilateral and usually symmetric increased lung markings. These findings resolve within 1-2 days. Lung volumes may be normal or increased. Pleural effusion and fluid in the fissures may or may not be present.

Differential considerations include:

• Congenital heart disease: Total anomalous pulmonary venous return (TAPVR), severe aortic obstruction (stenosis, coarctation, interruption), hypoplastic left heart
• Meconium aspiration syndrome: Hyperinflated lungs with rope-like perihilar markings
• Neonatal pneumonia: