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GI RADIOLOGY Table of Contents   
Year : 2007  |  Volume : 17  |  Issue : 2  |  Page : 77-78
Images: Hepato-biliary ascariasis

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How to cite this article:
Oswal K, Agarwal A. Images: Hepato-biliary ascariasis. Indian J Radiol Imaging 2007;17:77-8

How to cite this URL:
Oswal K, Agarwal A. Images: Hepato-biliary ascariasis. Indian J Radiol Imaging [serial online] 2007 [cited 2021 Feb 25];17:77-8. Available from:
A 40-years-old woman presented with a two months history of recurrent, intermittent abdominal pain, in the right hypochondrium. On examination, there was mild tenderness in the right hypochondrium.

Ultrasound (USG) of the abdomen revealed a well-distended gall bladder with a wall thickness of 2 mm and no evidence of calculi. The liver was mildly enlarged. There were tubular, non-shadowing structures with highly echogenic walls and less echogenic centers, within the intrahepatic biliary radicles in both lobes of the liver and the common hepatic duct. These were highly suggestive of Ascariasis [Figure - 1],[Figure - 2],[Figure - 3]. The common bile duct was 6 mm in diameter. No worm was seen in the extrahepatic bile duct.

   Discussion Top

USG of the abdomen has been advocated as a quick, safe, noninvasive and relatively inexpensive modality for suspected biliary ascariasis and various appearances of roundworms in the biliary tract and gallbladder have been described. [1],[2] The appearances described are as follows:

  1. Inner-tube sign: The roundworm may be seen as a thick echogenic stripe with a central anechoic tube (gastrointestinal tract of the worm) in a gall bladder or CBD [Figure - 2],[Figure - 3].
  2. Stripe sign: Thin non-shadowing stripe without an inner tube, within the CBD or gall bladder [Figure - 1].
  3. Spaghetti sign: Overlapping longitudinal interfaces in the main bile duct due to coiling of a single worm or several worms in the CBD.

The differential diagnosis of increased echogenecity within the biliary tree, either diffuse or focal, includes calculus, sludge, pus, thrombus, tumor, gas, foreign body and parasites. Calculus or calculi were excluded in this case because the intraluminal echogenic regions did not shadow and did not consist of one or multiple round or oval echogenic areas. Sludge, pus and thrombus would not be expected to be so discretely tubular and smaller in cross-sectional area than the common duct and would also appear more amorphous, lacking the prominently echogenic walls demonstrated in this case. [3],[4] Many tumors may involve the common hepatic bile duct or the common bile duct, but no tumor has an appearance that simulates the long, well-defined, tubular, constant-diameter, intraluminal abnormality surrounded by bile that is present in this case. [3],[5]

A lumbricoides infects approximately 1 billion people worldwide. [6] It is distributed throughout the tropics and subtropics and is also present in other humid regions such as the rural southeastern United States. [6]

The human infection life cycle begins by ingestion of an egg, with the larvae hatching in the small intestine. The larvae invade the small-bowel mucosa, migrate through the circulatory system to the lungs, invade the alveoli, ascend the tracheobronchial tree and then are swallowed into the small intestine where they mature into adult worms. [6]

Ascarids may reach 40 cm in length with a width of 3-6 mm. Intestinal infestation is often asymptomatic. Migration of worms into the biliary tree is a well-known complication, which may result in biliary colic, cholecystitis, cholangitis, intrahepatic abscesses or pancreatitis. [4] After cholelithiasis, it is the second most common cause of acute biliary symptoms worldwide. [7]

There is evidence to suggest that sphincterotomy predisposes a patient to biliary ascariasis. Jaundice and elevated liver enzyme may occur. The diagnosis is established by means of microscopic identification of A lumbricoides eggs in fecal samples. An A lumbricoides worm occasionally is identified in stool or vomitus. [6] USG readily depicts the worm in the bile ducts or gallbladder. [7],[8] Mebendazole (three days of twice daily oral therapy) or albendazole (a single oral dose of medication) are the treatments of choice. [6]

   References Top

1.Cerri GG, Leite GJ, Simoes JB, Correia Da Rocha DJ, Albuquerque FP, Machado MC, et al . Ultrasonographic evaluation of Ascaris in the biliary tract. Radiology 1983;146:753-4.  Back to cited text no. 1    
2.Schulman A, Loxton TA, Heydenrych JJ, Abdurahman EK. Sonographic diagnosis of biliary ascariasis. AJR Am J Roentgenol 1982;139:485-9.  Back to cited text no. 2    
3.Bude RO, Bowerman RA. Biliary ascariasis. Radiology 2000;214:844-7.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]
4.Suri A, Bhatia M, Chander BN, Chaturvedi A. Images: Hepatobiliary ascariasis. Indian J Radiol Imaging 2002;12:221-3.  Back to cited text no. 4    
5.Robledo R, Muro A, Prieto ML. Extrahepatic bile duct carcinoma: US characteristics and accuracy in demonstration of tumors. Radiology 1996;198:869-73.  Back to cited text no. 5  [PUBMED]  
6.Liu LX, Weller PF. Intestinal nematodes. In : Fauci AS, Braunwald E, Isselbacher KJ, et al , editors. Harrison's principles of internal medicine. 15 th ed. McGraw-Hill: New York, NY; 1998. p. 1208-9.  Back to cited text no. 6    
7.Mani S, Merchant H, Sachdev R, Rananavare R, Cunha N. Sonographic evaluation of biliary ascariasis. Australas Radiol 1997;41:204-6.  Back to cited text no. 7  [PUBMED]  
8.Khuroo MS, Zargar SA, Mahajan R. Hepatobiliary and pancreatic ascariasis in India. Lancet 1990;335:1503-6.  Back to cited text no. 8  [PUBMED]  

Correspondence Address:
Ajay Agarwal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.33614

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  [Figure - 1], [Figure - 2], [Figure - 3]


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