Biliary Ascariasis: A Rare but Treatable Cause of Biliary Obstruction

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 Biliary Ascariasis: A Rare but Treatable Cause of Biliary Obstruction

Keywords: biliary ascariasis, Ascaris lumbricoides, ERCP, obstructive jaundice, parasitic infection, albendazole, hepatobiliary imaging, gastrointestinal parasites

Introduction

Biliary ascariasis is a parasitic infestation of the biliary tree by Ascaris lumbricoides, an intestinal roundworm that may enter the hepatobiliary system, causing significant morbidity. Though common in endemic regions such as South Asia and parts of Latin America, it remains an underrecognized cause of obstructive jaundice and acute cholangitis in industrialized nations. This case study of a 75-year-old male patient highlights the clinical features, diagnostic modalities, and treatment strategies for biliary ascariasis, emphasizing its relevance in global health and radiological practice.

Case Presentation

A 75-year-old man presented to the emergency department with a 3-week history of fever, progressive abdominal pain, and pale-colored stools. On admission, he was febrile (38.2°C), and physical examination revealed right upper quadrant tenderness and clinical jaundice.

Laboratory findings were remarkable for:

  • Leukocytosis: 24,870/μL (normal: 4,000–10,000)

  • Neutrophilia

  • Total bilirubin: 3.8 mg/dL (normal: 0–1.2)

These findings indicated a systemic inflammatory response with cholestasis, suggestive of a biliary tract infection or obstruction.

Imaging and Endoscopic Findings

Ultrasonography

Ultrasound of the right upper quadrant demonstrated:

  • Dilated intrahepatic and extrahepatic bile ducts

  • Echogenic tubular structures consistent with biliary sludge and possibly parasites

Figure 1: Abdominal ultrasound image showing echogenic tubular structure (arrow) in the dilated common bile duct, suggestive of parasitic infestation.

Endoscopic Retrograde Cholangiopancreatography (ERCP)

ERCP was performed for both diagnostic and therapeutic purposes. During the procedure:

  • A live worm was seen emerging from the ampulla of Vater

  • The worm was retrieved and identified as an adult Ascaris lumbricoides

Subsequent cholangiography revealed additional worms within the common bile duct. A balloon catheter was used to extract two more worms.

Figure 2: ERCP cholangiogram showing multiple linear filling defects in the bile duct consistent with parasitic worms (arrows).

Diagnosis: Biliary Ascariasis

The patient was diagnosed with biliary ascariasis, confirmed by direct visualization and extraction of the worms during ERCP.

Pathophysiology

Ascaris lumbricoides eggs are ingested through contaminated food or water. The larvae hatch in the intestine, migrate through the lungs, and return to the gut where they mature. Adult worms occasionally enter the biliary system through the ampulla, especially during febrile illness, anesthesia, or pregnancy when sphincter tone is reduced.

Treatment and Outcome

The patient received:

  • Albendazole (400 mg, single dose) for anthelmintic therapy

  • Piperacillin-tazobactam for presumed secondary cholangitis

Clinical symptoms improved markedly within one week. Follow-up labs showed normalization of bilirubin levels and a drop in leukocyte count.

Discussion

Epidemiology

Biliary ascariasis is most commonly reported in:

  • India

  • Bangladesh

  • Pakistan

  • Middle East

  • South America

In endemic areas, Ascaris infections can recur due to environmental exposure and inadequate sanitation.

Clinical Features

FeatureFrequency (%)
Right upper quadrant pain   95%
Jaundice   80%
Fever   70%
Nausea/Vomiting   65%
Pale stools   40%

Radiologic Clues

  • Ultrasound: Long, tubular, mobile echogenic structures (“strip sign”, “spaghetti sign”)

  • ERCP/MRCP: Linear filling defects in bile ducts

  • CT: Can show intraductal worms, but is less sensitive than ultrasound

Differential Diagnoses

  • Choledocholithiasis (bile duct stones)

  • Biliary stricture

  • Cholangiocarcinoma

  • Primary sclerosing cholangitis

  • Clonorchiasis

Management Strategy

StepPurpose
ERCP     Diagnosis + worm extraction
Anthelmintics     Kill residual intestinal worms
Antibiotics     Treat secondary infections
Follow-up imaging     Monitor for recurrence

Public Health Implications

Biliary ascariasis underscores the intersection of parasitic disease and gastrointestinal practice. With increasing globalization, clinicians must consider parasitic infections even in developed settings, particularly among immigrants, travelers, and immunocompromised patients.

Prevention strategies include:

  • Improved sanitation

  • Deworming programs

  • Health education

Quiz

1. A 75-year-old man presents with fever, jaundice, and progressive abdominal pain. Ultrasound reveals echogenic tubular structures in the dilated common bile duct. ERCP shows a worm emerging from the ampulla, which is identified as the causative agent of biliary ascariasis. What is the most likely causative organism?

A. Clonorchis sinensis
B. Ascaris lumbricoides
C. Schistosoma haematobium
D. Taenia saginata

2. Which imaging or procedural technique was used in this case to both diagnose and extract the parasitic worms from the biliary tract?

A. Abdominal X-ray
B. Abdominal Ultrasound
C. Endoscopic Retrograde Cholangiopancreatography (ERCP)
D. Magnetic Resonance Cholangiopancreatography (MRCP)

Answer & Explanation

1. Correct Answer: B. Ascaris lumbricoides. Explanation: Ascaris lumbricoides is the most common cause of biliary ascariasis. The adult worms can migrate from the small intestine into the biliary tract, causing obstruction, cholangitis, or pancreatitis. While Clonorchis sinensis also inhabits the biliary tree, it presents differently (multiple thin flukes) and usually causes chronic disease rather than acute obstruction. ERCP confirming a single adult roundworm emerging from the ampulla supports Ascaris infection.

2. Correct Answer: C. Endoscopic Retrograde Cholangiopancreatography (ERCP). Explanation: ERCP is a diagnostic and therapeutic endoscopic technique that allows for direct visualization and extraction of obstructions in the biliary and pancreatic ducts. In this case, it enabled visualization of a live Ascaris worm emerging from the ampulla and allowed for the successful removal of additional worms with a balloon catheter. Ultrasound and MRCP are non-invasive but cannot be used for direct removal.

Conclusion

Biliary ascariasis is a rare but reversible cause of biliary obstruction. Timely diagnosis via ultrasound and ERCP is crucial for symptom resolution and the prevention of complications. This case serves as a reminder to include parasitic infections in the differential diagnosis of obstructive jaundice, especially in high-risk populations.

References

  1. J. K. Das, et al., “Biliary ascariasis: diagnosis and management,” World J Gastroenterol., vol. 20, no. 43, pp. 16190–16195, 2014.

  2. G. Sharma and A. Anand, “Endoscopic management of biliary ascariasis,” Gastrointest Endosc., vol. 79, no. 5, pp. 748–749, 2014.

  3. M. Khuroo, “Ascariasis,” Gastroenterol Clin North Am., vol. 26, no. 3, pp. 617–630, 1997.

  4. S. Mahmood et al., “Radiologic imaging in biliary ascariasis,” AJR Am J Roentgenol., vol. 178, no. 4, pp. 979–981, 2002.

  5. J. A. Horton, “Albendazole: a review of anthelmintic efficacy,” Trans R Soc Trop Med Hyg., vol. 101, no. 1, pp. 29–36, 2007.

  6. K. Tandon et al., “Biliary parasitosis: ultrasonographic findings,” J Ultrasound Med., vol. 20, no. 4, pp. 379–383, 2001.

  7. A. S. Misra et al., “Therapeutic ERCP in biliary ascariasis,” Indian J Gastroenterol., vol. 23, no. 1, pp. 6–7, 2004.

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