Ascariasis of gallbladder: a rare case report and a review of the literature

Introduction

The round worm named as ascaris lumbricoides is the most common helminthic infection (nematode) in humans. ¹ The adult nematode worm is mainly present in the small intestine.^1,2

Sometimes the worm enters into the common bile duct, passing through the papilla of water present in the second part of duodenum and then into the gallbladder lumen through the cystic duct. This is a very rare presentation. We report a rare case of gallbladder ascariasis with intrahepatic biliary radicles ascariasis.

Case report

A 15-year-old boy presented to the outpatient clinic with complaints of pain in the abdomen, vomiting, pruritus, and fever on-and-off for 10 days. There was also history of multiple episodes of passing worms in the stool for 20 days. On examination he was thin and toxic in appearance and jaundice was present. His vitals were normal except for a raised temperature. On laboratory investigation, his haemoglobin was 10 gm%, total white blood count (WBC) – 20,000/mm³. A liver function test (LFT) showed serum bilirubin – 5.6 mg/dL, alkaline phosphatase (ALP) – 160 IU/L, angiotensin sensitivity test (AST) – 140 IU/L, and alanine aminotransferase (ALT) – 98 IU/L.

On radiological examination, an ultrasonography of the abdomen showed a dilated gallbladder with multiple linear echogenic, tubular, parallel lines inside the lumen of the gallbladder, common bile duct and intrahepatic biliary radicles (Figures 1 and 2). The common bile duct was dilated with a diameter of approximately 12 mm with dilatation of the biliary radicles. The zigzag and coiling movement of the worm was noted in the lumen of the gallbladder on real time B-mode ultrasonography. Mild hepatomegaly was also noted. There was no evidence of cholecystitis. OPEN IN VIEWER

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Figure 2.

Ultrasonography of the abdomen showing dilated intrahepatic biliary radicles with multiple linear echogenic, tubular and parallel lines inside the lumen.

A diagnosis of ascariasis of the gallbladder and common bile duct was made and the anthelminthic drug albendazole (400 mg/day) was given. The patient improved after 10 days of multiple episodes of the passage of worms in his stools.

Discussion

Ascariasis is caused by Ascaris lumbricoides roundworms which belong to the phylum nematode and is the most common helminthic infection in humans. ¹ The prevalence is worldwide but occurs most often in tropical and subtropical countries. The adult worm is usually seen in the small intestine, mainly in the jejunum. The infection occurs mainly in developing countries due to poor sanitation, unhygienic conditions, and overcrowding, as the route of transmission is faeco-oral. The adult worm enters the common bile duct and main pancreatic duct from the second part of the duodenum through an ampulla of water and then goes into the gallbladder lumen through the cystic duct which is relatively rare. Only 2.1% of all cases involve the biliary tract. ³ The incidence is low because of tortuous and narrow cystic duct. ⁴

Biliary ascariasis presents with complaints of right upper abdominal quadrant pain, low grade fever, vomiting, tenderness of the abdomen, and multiple episodes of passage of worms in the stools. The complications can look like acute cholangitis if the obstruction occurs in the common bile duct and presents with fever, jaundice, and tender hepatomegaly. Sometimes it can cause acute cholecystits due to the obstruction of the cystic duct and as acute pancreatitis due to the obstruction of the main pancreatic duct.^5,6

On radiological examination, ultrasonography is the modality of choice for the diagnosis of gallbladder ascariasis because the appearance and movement of live worms can be seen. ⁵ The live worm presents as linear, tubular, parallel, non-shadowing echogenic lines inside the gallbladder lumen and shows coiling, zigzag and non-directional movements which confirm that the worm is alive. ⁷

A computed tomography (CT) scan shows tubular hyperdense foci in the gallbladder and common bile duct lumen with dilatation of the intrahepatic biliary radicles.

Conclusion

Treatment includes anthelminthic drugs. Most commonly albendazole is given and in most cases the patient responds well to medical management. Sometimes surgery is required, usually laparoscopic or endoscopic procedures such as endoscopic retrograde cholangiopancreatographic (ERCP) examination^8,9 if the worm is dead and causing obstructive in the biliary system. However, in this case the patient responded well to anthelminthic drugs and no intervention was required. On follow-up, no evidence of the worm was noted in the gallbladder or the common bile duct lumen.