1. Image Challenge Q:
A 23-day-old male infant was brought to the emergency department after 5 days of increasing vomiting. Physical exam revealed mild dehydration and an olive-sized abdominal mass. Upper gastrointestinal radiography showed a distended, air-filled stomach. What is the likely diagnosis?
1. Gastric duplication
2. Pyloric stenosis
3. Duodenal atresia
4. Intestinal malrotation
5. Mid-gut volvulus

2. Image Challenge Q:
A 23-day-old male infant was brought to the emergency department after 5 days of increasing vomiting. Physical exam revealed mild dehydration and an olive-sized abdominal mass. Upper gastrointestinal radiography showed a distended, air-filled stomach. What is the likely diagnosis?
Answer:
Pyloric stenosis
The correct answer is pyloric stenosis. The radiograph reveals undulating contours of the stomach -— known as the “caterpillar” sign -— visible when hyperperistaltic waves end abruptly at the pylorus, characteristic of infantile hypertrophic pyloric stenosis.