Double bubble sign in the x-ray is the characteristic of?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Child Health Nursing (Pediatrics)

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Explanation

The 'double bubble' sign is a classic radiological finding on an abdominal X-ray, representing two distinct air-filled bubbles.
The first, larger bubble is the stomach, and the second, smaller bubble is the dilated proximal duodenum.
This pattern is pathognomonic for complete duodenal obstruction because a blockage (atresia) prevents air from passing into the distal bowel.
Duodenal atresia, a congenital closure of the duodenum, is the most common cause of this sign.
The absence of gas in the lower parts of the abdomen on the X-ray further confirms a complete obstruction.

Option A: Pyloric stenosis is an obstruction at the outlet of the stomach. On an X-ray, this would present as a single large, distended gastric bubble, not a double bubble.
Option B: Tracheo-oesophageal fistula (TEF) is an abnormal connection between the esophagus and trachea. The characteristic X-ray finding is a nasogastric tube coiling in the upper esophageal pouch, not a double bubble sign.
Option C: Hirschsprung's disease is a functional obstruction of the large intestine due to the absence of ganglion cells. It does not cause a double bubble sign.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Radiological signs of neonatal intestinal obstruction as background academic context rather than a clinical decision trigger.
Recognizing the double bubble sign is critical for the prompt diagnosis of duodenal atresia, which is a neonatal surgical emergency requiring timely intervention to prevent complications.
Nursing priorities for an infant with suspected duodenal atresia include immediate gastric decompression via an NG/OG tube, maintaining NPO status, and administering IV fluids to stabilize the patient for surgery.
Duodenal atresia has a strong association (up to 40%) with Trisomy 21 (Down syndrome). Nurses should be aware of this and assess for other associated anomalies, particularly congenital heart defects.

How to Approach the Question

First, identify the key term in the question stem: 'double bubble sign'. This is a classic, high-yield radiological finding.
Recall the anatomical basis of this sign: it represents air trapped in the stomach and the proximal duodenum.
This immediately points to an obstruction at the level of the duodenum, preventing air from moving distally.
Systematically evaluate the options based on this understanding:
Pyloric stenosis is a gastric outlet obstruction (single bubble).
Tracheo-oesophageal fistula involves the esophagus and trachea (coiled NG tube).

Concept Tested & Keywords

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E6 Obstetrics Williams p. 69-95

E6 Nelson Textbook of Pediatrics(2024) — Volume 2 pp. 63-65, 64-66