**6. Investigations**

Once duodenal obstructions is suspected, a plain abdominal radiograph is usually sufficient to make the diagnosis. Typically, a double-bubble sign with no distal

abdominal air is seen (**Figure 3**). The first bubble to the left represents the gastric air, while the right bubble represents air within a dilated proximal duodenum [21]. Distally, the abdomen is almost always gasless in complete duodenal obstruction, except in cases of incomplete obstruction or the rare cases of bifid common bile duct associated with duodenal atresia [22]. Upper GI contrast studies are usually not necessary unless incomplete obstruction or malrotation is suspected. To assess for concomitant congenital cardiac malformation, echocardiography should be performed.
