Intestinal ascariasis: new plain film features.

Radiographs from 30 children with intestinal obstruction caused by a bolus of Ascaris worms were analyzed. Worms could be seen outlined against intestinal gas; the interface between worm bolus and adjacent gas shadows was irregular. Gas trapped within the worm bolus had irregular outlines. There were also fine linear radiolucent shadows and small bubbles. Fluid levels were sometimes distorted by a projecting worm bolus, resulting in a hump effect. Some of the radiolucencies were within the worms. These features were used in an analysis of radiographs from 68 children who did not have bolus obstruction. Of 44 children with proven ascariasis, 28 (64%) had suggestive radiologic features. In four of 24 children without Ascaris ova in the stools, confusion with fecal shadows resulted in a false-positive diagnosis on the radiographs. Recognition of the worm infestation in asymptomatic patients is important because intestinal malabsorption may contribute to nutritional deficiency.