Ascariasis biliary obstruction — DTM&H MCQ

Correct answer: B — Supportive care with endoscopic removal if obstructed

The correct answer is B, supportive care with endoscopic removal if obstructed. The ultrasound finding of a long tubular motile structure in the common bile duct in a child from an Ascaris lumbricoides endemic area (rural Bangladesh) with colicky right upper quadrant pain is classic for biliary ascariasis, where an adult worm migrates from the duodenum into the biliary tree. Initial management is conservative (analgesia, antispasmodics, hydration) because worms often migrate spontaneously back into the duodenum, and anthelminthic therapy is given once the acute obstruction settles. If obstruction, cholangitis or pancreatitis persists or the worm does not pass spontaneously, endoscopic retrograde cholangiopancreatography (ERCP) with mechanical extraction is the definitive intervention, as this is both diagnostic and therapeutic and avoids the morbidity of open surgery. This staged approach (conservative first, endoscopy for failure or complications) reflects the standard described in tropical medicine and endoscopy literature. Why the other options are wrong: C. Metronidazole alone: This treats protozoal or anaerobic bacterial infection, not nematode infestation; Ascaris is unaffected by metronidazole. E. Liposomal amphotericin: This is antifungal/antileishmanial therapy and has no role in helminthic biliary obstruction. D. Praziquantel: This is used for trematodes (schistosomiasis, liver flukes) and cestodes, not for Ascaris lumbricoides, which requires benzimidazoles such as albendazole, and even then only after the acute obstructive episode is managed. A. Rabies vaccine: There is no exposure history or clinical feature suggesting rabies; this is irrelevant to a biliary motile worm. Key point: A migratory tubular structure in the CBD on ultrasound in an endemic child is biliary ascariasis, managed conservatively first with ERCP reserved for persistent obstruction or complications, followed by anthelminthic treatment.

Reference: ScienceDirect review, Biliary parasitic disease management: conservative measures with analgesics and anti-helminthic therapy first-line, endoscopic biliary drainage and worm extraction reserved for refractory cases or acute cholangitis (https://www.sciencedirect.com/science/article/abs/pii/S0016510788713644)