**Question:** A 4-day-old male infant vomits the contents of his stomach, but the vomitus does not appear to contain bile. The baby is obviously distressed and makes sucking movements of his lips in response to offerings to suckle by his mother or of the bottle, but he is failing to thrive. Which of the following conditions will best explain the symptoms?

A. Congenital Hypothyroidism
B. Congenital Diaphragmatic Hernia
C. Congenital Gastric Atresia
D. Congenital Total Anomalous Pulmonary Venous Return

**Correct Answer:** C. Congenital Gastric Atresia

**Core Concept:** Congenital Gastric Atresia is a rare congenital gastrointestinal anomaly characterized by the absence of communication between the stomach and the rest of the gastrointestinal tract.

**Why the Correct Answer is Right:** The correct answer (C) is chosen because it explains the symptoms presented by the infant:

1. Vomiting of the stomach contents without bile: This is due to the inability of the stomach to communicate with the rest of the gastrointestinal tract, which prevents the passage of bile into the vomitus.
2. Distress and sucking movements: These symptoms are indicative of the infant's attempts to feed and receive nourishment, but due to the gastric atresia, the infant is unable to properly digest or utilize the ingested food.
3. Failure to thrive: The absence of effective digestion and absorption leads to inadequate growth and development in the affected infant.

**Why Each Wrong Option is Incorrect:**

A. Congenital Hypothyroidism (Option A) and D. Congenital Total Anomalous Pulmonary Venous Return (Option D) are unrelated to the infant's vomiting and failure to thrive. Hypothyroidism affects hormone production, while Total Anomalous Pulmonary Venous Return pertains to pulmonary circulation anomalies and is not related to digestion or feeding issues.

B. Congenital Diaphragmatic Hernia (Option B) presents with respiratory distress, lung hypoplasia, and abdominal distension due to herniation of abdominal contents into the thoracic cavity, which is different from the symptoms described in the question.

**Clinical Pearl:**

Atresia is a term used to describe the absence or incomplete development of a specific body structure, in this case, the stomach. In congenital gastric atresia, the stomach fails to develop or becomes non-functional, resulting in the symptoms mentioned above. This condition can be diagnosed through imaging studies, such as ultrasound or barium studies, which demonstrate the absence of contrast passage through the stomach. Treatment typically involves surgical intervention, such as gastrostomy tube placement or gastrojejunostomy to bypass the gastrointestinal tract and provide direct access to feed the infant.