The radiological findings in <i>Ascaris lumbricoides</i> infection

Clinical History

Patient admitted with complaints of colicky abdominal pain and vomiting.

Imaging Findings

The patient was admitted with complaints of colicky abdominal pain and vomiting. She had experienced a weight loss of approximately 5kg in 2 months.

Ultrasound examination of the upper abdomen revealed linear echogenic lesions in the gallbladder extending to the common bile duct (Fig. 1a). Barium enema examination of the stomach, small bowel and colon revealed multiple curvilinear translucent filling defects distributed widely throughout the intestinal segments (Figs 1b-d).

Microbiological analysis of stool confirmed Ascaris lumbricoides infection.

Discussion

Ascaris lumbricoides is the most common intestinal parasite to infect humans. The incidence of ascaris infection is increasing in all part of the world because of world travel and population migration. A. lumbricoides may cause various complications in the gastrointestinal system. Abdominal pain and tenderness with weight loss are the most common clinical presentations. The worm can cause invagination at the intestinal segments and can enter the bile duct and cause cholangitis or biliary colic. Biliary ascariasis, however is a rare condition.

Ascaris roundworms are seen as cylindrical filling defects within contrast filled bowel loops. The appearances in longitudinal section are termed the "strip sign", "spaghetti sign" and "inner tube sign". In transverse section "a bull's eye in the triple O" sign is seen. These appearances are characteristic of ascaris but can also be seen in other forms of parasitosis. The helminth can travel out of the biliary duct system back into the intestines, so subsequent US and barium examinations can even be negative. Faecaloids may mimic the appearances of ascaris. Microbiological and clinical analysis confirms the diagnosis.

Differential Diagnosis List

Final Diagnosis

Gastrointestinal involvement in Ascaris lumbricoides infection

URL:	https://www.eurorad.org/case/1434
DOI:	10.1594/EURORAD/CASE.1434
ISSN:	1563-4086