Review Question - QID 105409

This infant's presentation is consistent with congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) occurs when a congenital defect in the diaphragm allows the herniation of abdominal viscera into the chest. Compression of the lungs and shift of the mediastinum occurs, resulting in the cyanosis and right-sided heart sounds observed on physical exam. The severity of respiratory distress is dependent on the extent of pulmonary hypoplasia and persistent pulmonary hypertension that accompany the disease. The first step in the treatment of CDH is placement of an orogastric tube and initiation of suction to prevent air from entering the bowel, which would further exacerbate the compression of the airway.

Bragg et al. discuss Morgagni hernias: "Morgagni hernia is a congenital diaphragmatic hernia that occurs secondary to potential anterior medial defects in the diaphragm. Surgical repair is required in all cases and may be performed with either the abdominal or transthoracic approach." Note that a postero-lateral diaphragmatic hernia, known as a Bochdalek hernia, is the most common type of CDH.

Sluiter et al. discuss the basic science behind the development of pulmonary hypertension in CDH: "The high mortality and morbidity of CDH patients are primarily caused by the associated pulmonary hypertension, characterized by the thickening of the vascular media and adventitia. The media consist of heterogeneous populations of vascular smooth muscle cells (VSMC), ranging from synthetic to the characteristic contractile cells. VSMCs are influenced by developmental and environmental cues and may play a role in the development of the structural changes observed in CDH patients."

Image A shows abdominal contents in the left lung field. Note also the scaphoid abdomen typical of CDH alluded to on physical exam.

Incorrect answers:
Answer 1: Neonatal respiratory distress syndrome (aka, hyaline membrane disease) presents with cyanosis and dyspnea at birth. The disease develops in premature infants with insufficient surfactant. The presence of a scaphoid abdomen in the patient in question makes congenital diaphragmatic hernia more likely.
Answer 2: Pulmonary hypertension is associated with congenital diaphragmatic hernia, but the condition is secondary to CDH, not idiopathic.
Answer 3: Potter's syndrome is a constellation of findings in the neonate secondary to oligohydramnios, including pulmonary hypoplasia, bilateral renal agenesis, and clubbed feet.
Answer 5: Transposition of the great vessels presents with extreme cyanosis and "egg-on-a-string" appearance on CXR.