A 4-hour-old girl is evaluated in the neonatal intensive care unit. The patient was born at 30 weeks gestation via spontaneous vaginal delivery after 3 hours of labor. Membranes ruptured at the onset of labor and amniotic fluid appeared clear. Immediately after birth, the child was placed on continuous positive airway pressure by nasal prongs due to signs of breathing difficulty. Temperature is 36.7 C (98 F), pulse is 158/min, and respirations are 54/min. Pulse oximetry is 92% on 60% oxygen. Examination shows audible grunting and subcostal chest wall retractions. Cardiac examination shows no murmurs. A chest x-ray is obtained: The radiographic findings in this patient most likely represent which of the following?

Question

A 4-hour-old girl is evaluated in the neonatal intensive care unit.  The patient was born at 30 weeks gestation via spontaneous vaginal delivery after 3 hours of labor.  Membranes ruptured at the onset of labor and amniotic fluid appeared clear.  Immediately after birth, the child was placed on continuous positive airway pressure by nasal prongs due to signs of breathing difficulty.  Temperature is 36.7 C (98 F), pulse is 158/min, and respirations are 54/min.  Pulse oximetry is 92% on 60% oxygen.  Examination shows audible grunting and subcostal chest wall retractions.  Cardiac examination shows no murmurs.  A chest x-ray is obtained:  The radiographic findings in this patient most likely represent which of the following?

Quizplus · Accepted Answer

11ec160b_3b3e_432a_9249_c17b488d7974_MD0001_00 This preterm infant with increased work of breathing and hypoxia has diffuse ground-glass opacities and air bronchograms on imaging. These findings are consistent with neonatal respiratory distress syndrome (RDS). RDS is caused by immaturity of type 2 pneumocytes, which normally produce alveolar surfactant. Lack of surfactant causes decreased compliance and increased surface tension of alveoli, leading to alveolar collapse at the end of expiration. This diffuse atelectasis results in the characteristic reticular or ground-glass opacities on chest x-ray. Unlike alveoli, larger airways remain patent and filled with air due to their cartilaginous walls, making them visible (air bronchograms) against the reticular background. Management of RDS is respiratory support (to maintain alveolar pressure and prevent collapse) and surfactant (to reduce surface tension). During the first week of life, type 2 pneumocytes begin to release endogenous surfactant, and respiratory distress typically begins to improve. (Choice A) Pneumothorax is characterized by air leakage into the pleural space with subsequent respiratory distress. However, x-ray would show a visceral pleural line with absent distal lung markings. (Choice B) Bronchopulmonary dysplasia (BPD), which causes tachypnea, retractions, and hypoxia, is classically caused by prolonged (>1 month) mechanical ventilation, leading to lung injury and diffuse fibrosis. Another form of BPD is caused by an arrest of pulmonary development, leading to a decreased number and function of alveoli and pulmonary capillaries. Although this infant is at risk for developing both forms of BPD due to prematurity, this condition is diagnosed at age >1 month, not immediately after birth. (Choice D) Occlusion of the bronchioles by meconium causes meconium aspiration syndrome. In contrast to this patient, affected infants have patchy bilateral infiltrates and lung hyperexpansion due to air trapping. In addition, this patient's amniotic fluid is clear, making this diagnosis unlikely. (Choice E) Retained extracellular fluid is seen in transient tachypnea of the newborn. X-ray findings include streaky interstitial fluid collections and fluid in the minor fissures, neither of which are seen in this patient. Educational objective: Neonatal respiratory distress syndrome is characterized by inadequate surfactant production, resulting in increased alveolar surface tension and decreased alveolar compliance. Diffuse alveolar collapse (atelectasis) is seen on chest x-ray as ground-glass opacities with air bronchograms. __________ References: Respiratory distress in the newborn. (http://www.ncbi.nlm.nih.gov/pubmed/25274969)

A 4-Hour-Old Girl Is Evaluated in the Neonatal Intensive Care