Biliary Ascariasis Mimicking Biliary Sludge on Abdominal Ultrasonography: Diagnosis and Worm Extraction by Snare During Side-Viewing Endoscopy at ERCP

Abstract

Introduction: Biliary ascariasis is a common parasitic infection in tropical countries, but is relatively rare in the United States. Common clinical presentations include biliary colic, acute cholangitis, acute cholecystitis, acute pancreatitis, or hepatic abscesses. A case is reported of the worm producing abnormal liver function tests, mimicking biliary sludge on abdominal ultrasound, and being successfully extracted during endoscopic retrograde cholangiopancreatography (ERCP). Case report: A 53-year-old female, immigrant to the United States from Bangladesh with prior cholecystectomy, and biliary sphincterotomy for cholelithiasis presented complaining of progressive abdominal pain for one month. Physical examination revealed a soft, nontender abdomen. The leukocyte count=16,100/mm3, with 14,300/mm3 neutrophils, and no eosinophilia. The serum alkaline phosphatase= 321 U/L, aspartate aminotransferase=428 U/L, alanine aminotransferase=232 U/L, total bilirubin= 1.5 mg/dl, and direct bilirubin=0.7 mg/dl. Serologies for viral hepatitis were all negative. Smooth muscle antibody, anti-mitochondrial antibody, celiac disease screen, and stool for ova and parasites were all negative. Abdominal ultrasound revealed a mildly dilated common bile duct (CBD) measuring 9 mm, containing a long segment, non-shadowing, echogenic material thought to represent sludge (Figure 1). Abdominal computed tomography and magnetic resonance cholangiopancreatography revealed extrahepatic dilatation attributed to the prior cholecystectomy. Endoscopic viewing before cannulation during ERCP revealed a curvilinear projection from the ampulla initially interpreted as a biliary stent. Closer examination showed the projection was a 12-cm-long nematode projecting from the ampulla (Figure 2), which was completely removed by snare. After cannulation, the CBD measured 10 mm in diameter. Sequential balloon pull-through resulted in extracting biliary sludge. Final occlusion cholangiogram did not reveal any residual filling defects. An expert parasitologist identified the nematode as an adult Ascaris lumbricoides. Patient was treated with one dose of albendazole 400 mg administered orally. The abdominal pain rapidly resolved and the liver function tests rapidly decreased towards normal before discharge.Figure 1Figure 2Discussion: This case report emphasizes that biliary ascariasis should be considered in the differential of chronic abdominal pain and abnormal liver function tests in patients from endemic regions, that the worm may mimic biliary sludge during abdominal ultrasound, and that it may be diagnosed and treated by ERCP.