A 10-minute-old girl is evaluated in the neonatal intensive care unit for respiratory distress, which has been present since birth. She was born at 40 weeks’ gestation via cesarean section for breech positioning. Amniotic fluid was clear. Vital signs are significant for normal temperature, respirations 60/minute, and O2 saturation of 82% in the right upper extremity. On physical examination, auscultation of the chest is positive for bowel sounds.
Which of the following is the most likely cause of this patient’s respiratory distress?
C) Lung hypoplasia
The presence of bowel sounds in the chest is suggestive of a congenital diaphragmatic hernia. Invasion of bowel into the thoracic cage results in pulmonary hypoplasia and resulting respiratory distress at birth. Chest x-ray would show loops of air-filled bowel in the thoracic cage.
Answer choice A: Inadequate amniotic fluid clearance, is incorrect. This describes transient tachypnea of the newborn. It is characterized by a chest x-ray with increased perihilar markings and interlobar fluid accumulation. It typically self-resolves within 2 days.
Answer choice B: Infection, is incorrect. Although pneumonia can result in respiratory distress, additional signs of infection would be expected such as temperature instability, history of maternal infection, and/or auscultatory findings consistent with pleural effusion or consolidation.
Answer choice D: Surfactant inactivation, is incorrect. Although meconium can inactivate surfactant and thereby result in respiratory distress, the amniotic fluid was clear in this case, decreasing the likelihood of meconium aspiration.
Answer choice E: Surfactant insufficiency, is incorrect. Respiratory distress syndrome results from low levels of surfactant and typically presents within hours of birth in premature newborns. This newborn was born at term gestation. In respiratory distress syndrome, chest x-ray would typically show diffuse ground glass opacities with air bronchograms.
Key Learning Point
Determining the etiology of newborn respiratory distress requires consideration of physical exam findings (vitals, auscultation), gestation history (full term vs premature), and imaging findings (chest x-ray). The presence of bowel sounds in the chest is suggestive of a congenital diaphragmatic hernia which results in lung hypoplasia and respiratory distress at birth.
