What ultrasound finding typically indicates a duodenal obstruction?

The presence of a double bubble sign on ultrasound is a classic indication of duodenal obstruction. This finding reflects the accumulation of fluid in the stomach and the first portion of the duodenum, which are both distended due to the blockage. The “double bubble” appearance specifically indicates that there are two distinct fluid-filled areas: the enlarged stomach and the proximal duodenum, which is unable to progress further due to the obstruction. This can occur due to various conditions, such as congenital duodenal atresia or other anatomic abnormalities.

In contrast, a single bubble might indicate either a dilated stomach without duodenal involvement or another type of obstruction. A triple bubble implies that there is obstruction further down the intestinal tract, typically at the level of the jejunum or ileum, and fluid has filled multiple loops of the bowel. Fluid-filled intestines can be seen in various bowel obstructions but are less specific and do not definitively indicate a duodenal obstruction like the double bubble does. Thus, the double bubble sign is particularly significant for identifying duodenal obstructions and guides further clinical evaluation and management.