A 30-year-old woman from a rural endemic area presents with sudden onset severe colicky right upper quadrant pain and vomiting. Ultrasound shows a linear echogenic shadow with a central anechoic tube in the common bile duct. What is the most likely causative organism?
- A Ancylostoma duodenale
- B Ascaris lumbricoides ✓
- C Fasciola hepatica
- D Taenia solium
Correct answer: B. Ascaris lumbricoides
Explanation
Ascaris lumbricoides adults can migrate from the duodenum into the biliary tree, causing biliary colic or obstruction. The ultrasound finding of a linear echogenic shadow with a central anechoic tube is pathognomonic for an adult worm in the bile duct. Ancylostoma causes iron deficiency anemia. Fasciola causes liver fluke infection with different imaging. Taenia solium causes intestinal taeniasis or cysticercosis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.