Chapter 37. Congenital Anomalies of the Respiratory System
A term infant shows respiratory distress 0.5 hours after delivery, cyanosis with tachypnea, marked sternal retractions, and decreased breath sounds over the left hemithorax. One examiner hears bowel sounds over the left lower lobe; a chest x-ray shows normal vascular markings, multiple cystic areas on the left, decreased aeration on the right, and right mediastinal shift. What is the most likely diagnosis in this patient?
a. Severe neonatal bacterial pneumonia
b. Congenital diaphragmatic hernia
c. Congenital cystic adenomatoid malformation
d. Extralobar sequestration
e. Congenital lobar emphysema
The most correct answer is b.
Congenital diaphragmatic hernia on the left side displaces or compresses adjacent structures. The early onset of respiratory distress, absence of normal breath sounds but clearly heard bowel sounds on the left, suggest gastric intrusion into the left hemithorax. Pneumonia (answer a), CCAM (answer c), and lobar sequestration (answer d) rarely present as life-threatening at birth and do not explain the bowel sounds. Left lobar emphysema (answer e) would be plausible in an older patient in view of the absent breath sounds and mediastinal shift, notably if actual lung hyperinflation had compressed the hilar vasculature.
A 2-year-old boy has wheezed since early in life and has not responded reliably to asthma therapy. He is described by caregivers as frequently having a congested chest and seems to choke on secretions. He is growing well but recently has developed shortness of breath while playing. A reconstructed CT scan of the boy's chest reveals the image shown at right. Which of the following best describes this patient's diagnosis?
b. Extralobar sequestration
e. Primary laryngomalacia
The most correct answer is a.
Tracheal stenosis is evident here as a strikingly tapered airway proximal to the carina. The patient's persistent wheeze that worsens with activity and fails to respond to bronchodilators is consistent with a fixed airway obstruction such as stenosis. The CT image does not provide sufficient detail to assess lung volume (answer c), lung sequestration (answer b), or impingement on central airways by a bronchogenic cyst (answer d). Given the absence of stridor or other more audibly divergent breath sounds and the narrowed tracheal profile make laryngomalacia (answer e) much less likely ...