A neonate at 38 weeks gestation is delivered vaginally following an uncomplicated pregnancy. Immediately after delivery, the neonate has respiratory distress. Examination shows cyanosis, tachypnea, and poor perfusion. The patient is emergently intubated, and mechanical ventilation is initiated. A nasogastric tube is also inserted. On auscultation, asymmetric aeration with decreased left-sided breath sounds are noted. The abdomen is scaphoid. A chest x-ray is shown in the exhibit.
Which of the following is the most likely cause of this patient's respiratory distress?

Question

A neonate at 38 weeks gestation is delivered vaginally following an uncomplicated pregnancy.  Immediately after delivery, the neonate has respiratory distress.  Examination shows cyanosis, tachypnea, and poor perfusion.  The patient is emergently intubated, and mechanical ventilation is initiated.  A nasogastric tube is also inserted.  On auscultation, asymmetric aeration with decreased left-sided breath sounds are noted.  The abdomen is scaphoid.  A chest x-ray is shown in the exhibit. 
 Which of the following is the most likely cause of this patient's respiratory distress?

Quizplus · Accepted Answer

11ec160b_374f_2e6d_9249_75158166907a_MD0001_00 This neonate has respiratory distress with asymmetric breath sounds and a scaphoid abdomen, findings concerning for congenital diaphragmatic hernia (CDH). This condition develops in the first trimester due to incomplete fusion of the pleuroperitoneal folds, which permits herniation of abdominal contents into the thoracic cavity (most commonly the left side). Compression of the developing lung results in pulmonary hypoplasia, or underdevelopment of lung tissue. Neonates typically develop respiratory distress (eg, tachypnea, retractions) within hours of birth and decreased unilateral breath sounds; a scaphoid abdomen from superiorly shifted abdominal viscera is common. Chest x-ray findings include the presence of thoracic bowel loops with minimal or absent lung markings and an indistinct hemidiaphragm on the affected side. In addition, the distal end of a feeding tube may be seen within the thorax instead of the abdomen. (Choices A and D) Pulmonary surfactant deficiency occurs in premature (not term) neonates and causes respiratory distress syndrome (RDS). X-ray reveals ground glass opacities and air bronchograms. RDS can be complicated by bronchopulmonary dysplasia, characterized by dilation of airspaces with bronchiolar metaplasia. Patients with CDH may also develop bronchopulmonary dysplasia, but this is a late complication (age >30 days) and is not present at birth. (Choice B) Pulmonary capillary wedge pressure reflects left ventricular end-diastolic pressure and is increased in left-sided congenital heart disease (eg, aortic stenosis). Poor perfusion would be expected, but a scaphoid abdomen and abnormally placed feeding tube would not be seen. (Choice C) Pneumothorax is characterized by loss of negative intrapleural pressure and can cause asymmetric breath sounds and respiratory distress. Although a mediastinal shift can also be seen on imaging, a visceral pleural edge (blue arrows) with the absence of distal lung markings would be expected. Educational objective: Congenital diaphragmatic hernia (herniation of abdominal contents into the thorax) causes pulmonary hypoplasia from compression of the lungs. Neonates present with respiratory distress shortly after birth. X-ray findings include thoracic bowel loops; the distal end of a feeding tube may also be seen within the thorax. __________ References: Congenital diaphragmatic hernia. (http://www.ncbi.nlm.nih.gov/pubmed/32310536) Congenital diaphragmatic hernia - a review. (http://www.ncbi.nlm.nih.gov/pubmed/28331629)

A Neonate at 38 Weeks Gestation Is Delivered Vaginally Following