A newborn boy is evaluated 30 minutes after birth. He was born at 39 weeks gestation to a 27-year-old primigravid mother via cesarean section for cervical insufficiency. The pregnancy was complicated by gestational diabetes and the amniotic fluid was clear. Upon delivery, the patient had strong respiratory effort and a strong cry. His Apgar scores at 1 and 5 minutes were 7 and 8, respectively. The patient now is exhibiting increased work of breathing and is progressively more tachypneic. His birth weight is 3,568 g (7 lb 14 oz). His temperature is 99.0°F (37.2°C), blood pressure is 60/44 mmHg, pulse is 146/min, and respirations are 72/min. On physical exam, the patient is grunting with nasal flaring and subcostal retractions. Breath sounds are decreased at the bases bilaterally. The patient has central cyanosis. His chest radiograph can be seen in Figure A. Which of the following is the most likely etiology of this patient’s presentation?
Meconium aspiration syndrome
Persistent pulmonary hypertension
Neonatal respiratory distress syndrome
Transient tachypnea of the newborn
Transient tachypnea of the newborn
This newborn is presenting with increased work of breathing and progressive tachypnea in the 1st hour of life, which is consistent with a diagnosis of transient tachypnea of the newborn.

Transient tachypnea of the newborn presents with respiratory distress and marked tachypnea within 2 hours of delivery. Transient tachypnea of the newborn is caused by delayed resorption and clearance of alveolar fluid, which results in mild pulmonary edema. Chest radiography typically demonstrates bilateral perihilar streaking and hyperinflation of the lungs. Transient tachypnea of the newborn is benign and usually resolves by day 2 of life. The management of this condition is supportive.

Alhassen et al. review the evidence regarding the diagnosis and treatment of TTN. They discuss how this condition sometimes requires extended hospitalization and is associated with wheezing in childhood. They recommend using ultrasound to help make this diagnosis.

Figure/Illustration A demonstrates prominent vascular markings around the hilum (yellow arrows), and increased lung volumes on chest radiograph, which is consistent with transient tachypnea of the newborn.

Incorrect Answers:
Answer A: Meconium aspiration syndrome can cause respiratory distress in the immediate newborn period, but it would be unlikely in a patient with a history of clear amniotic fluid, and a more mild clinical picture. Meconium aspiration syndrome would be seen on chest radiograph as coarse, irregular infiltrates and hyper expansion. Treatment is with antibiotics and airway clearance.

Answer B: Neonatal respiratory distress syndrome is a disease of prematurity and does not often occur in infants born at term to healthy mothers. The chest radiograph in neonatal respiratory distress syndrome is also more likely to demonstrate low lung volumes. Treatment is with surfactant administration.

Answer C: Persistent pulmonary hypertension is a cause of respiratory distress in the newborn period, but a chest radiograph typically shows clear lungs. Treatment is with respiratory support as well as inhaled nitric oxide.

Answer E: Viral pneumonia is uncommon in the immediate newborn period. Bacterial pneumonia is more common but usually presents with signs of infection in the mother, which are not present in this case. Treatment is with broad-spectrum antibiotics.

Bullet Summary:
Transient tachypnea of the newborn presents with worsening tachypnea within 2 hours of delivery and is caused by pulmonary edema resulting from inadequate clearance of alveolar fluid.