ABOG Oral Boards Obstetrics Practice Test

The diagnostic features of congenital diaphragmatic hernia (CDH) primarily include the presence of a thoracic mass and mediastinal shift. This occurs due to abdominal contents herniating into the thoracic cavity, which can be identified through imaging studies such as ultrasound. The presence of these herniated organs in the thorax leads to a characteristic appearance, often described as a "mass" effect in the chest, and results in the displacement of the mediastinum.

Informed recognition of the abdominal circumference can also play a role in the assessment of CDH. Typically, the abdominal circumference may appear smaller due to the displacement of abdominal organs and the potential for underdevelopment of the lungs that can complicate the condition. The lungs may fail to develop properly due to the presence of herniated viscera, leading to pulmonary hypertension and other respiratory complications once the neonate is born.

Other options mentioned might have features associated with various perinatal conditions but do not specifically encapsulate the distinctive diagnostic features of CDH like the combination of thoracic mass and mediastinal shift does. Understanding these critical signs will assist clinicians in making accurate diagnoses and improving outcomes for affected infants.