Primary ascaridial perforation of the small intestine: sonographic diagnosis.

Ascaris lumbricoides is the most common helminth affecting humans. Ascariasis can result in serious complications, including intestinal obstruction and perforation. Early diagnosis and treatment of such complications reduces the risk of mortality. We present a case of sonographically diagnosed ascaridial perforation in a 5-year-old girl. On sonography, each ascarid appeared as 2 pairs of parallel lines, representing the worm's outer margins, flanking a central sonolucent line, representing its digestive tract. Sonography revealed ascarides in the peritoneal cavity and in some loops of the small bowel. Emergent laparotomy was performed to remove ascarides from the peritoneal cavity and terminal ileum, and the patient recovered well and was asymptomatic at a 3-month follow-up. Knowledge of the sonographic features described herein may aid in the evaluation of patients, especially children, in tropical countries who have clinical symptoms of ascariasis.