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ABDOMINAL IMAGING Table of Contents   
Year : 2002  |  Volume : 12  |  Issue : 2  |  Page : 221-223
Images : Hepatobiliary ascariasis

Radiologist, Command Hospital Air Force, Bangalore-560007, India

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Keywords: Ascariasis, biliary, ultrasound

How to cite this article:
Suri A, Bhatia M, Chander B N, Chaturvedi A. Images : Hepatobiliary ascariasis. Indian J Radiol Imaging 2002;12:221-3

How to cite this URL:
Suri A, Bhatia M, Chander B N, Chaturvedi A. Images : Hepatobiliary ascariasis. Indian J Radiol Imaging [serial online] 2002 [cited 2020 Dec 3];12:221-3. Available from:

   Introduction Top

Hepato Biliary Ascariasis(HBA) is endemic in third world countries. Ascariasis in the hepatobiliary tract can cause acute cholecystitis, acute cholangitis, obstructive jaundice, acute pancreatitis and hepatic liver abscess. After gaining entry from the ampulary orifice the worms can freely move in and out of the biliary tree and at times the disease can be symptomless. Ultrasound is an excellent modality to diagnose and follow up hepatobiliary ascariasis. MRCP and CT are complimentary imaging techniques.

   Case Report Top

An 18 years old rural male presented with insidious onset of right hypochondrial pain which progressed in severity over the next 12 hours. There was associated nausea and vomiting. On examination there was tenderness and guarding in the right hypochondrium with a palpable gall bladder. He was treated with antispasmodics and the pain subsided intermittently. An urgent ultrasound performed showed a grossly dilated gall bladder with a curved cord like lesion emerging from the neck of the gall bladder. The lesion had an inner hypoechoic tube along its length [Figure - 1].There was thick, layered,non mobile sludge seen in the gall bladder fundus. The gall bladder wall was thickened (5.6 mm) and revealed wall edema with pericholecystic fluid. There was mild to moderate degree of dilation of the intra hepatic biliary radicles suggestive of obstructive jaundice. The margins of the common bile duct were obscure. On further examination it was seen to contain similar two to three isotohyperechoic cord like lesions, along the length of the common duct and entwined around each other. Some of the lesions showed an inner hypoechoic tube and no movements of these lesions could be appreciated. In addition there was a space occupying lesion seen in the left lobe of the liver measuring 43 mm x 52 mm x 38 mm. This lesion was round, heterogenous, predominantly hyperechoic, with a well defined capsule and without any significant probe tenderness. An usg diagnosis of helminthiasis impacted in the gall bladder neck and the CBD causing acute cholecystitis and obstructive jaundice was made. The left lobe lesion was most likely an abscess formed over an intraparenchymal worm. A plain CT scan abdomen performed on the same day confirmed the same findings as revealed on USG -curvilinear densities seen in the neck of the gall bladder and the CBD with a dilated biliary tree[Figure - 2].

The patient was put on antihelminthic treatment in the form of oral albendazole after which a usg abdomen revealed the intraluminal worm to have bunched up.Other findings remained the same.

The patient developed low grade fever (100F) the next day and jaundice (4 mg%).Liver enzymes were mildly elevated,SGOT 120 IU,SGPT 130 HU,Alkaline Phosphatase was 800 KA units. A MRCP performed showed linear filling defects in an enlarged CBD with a distended gall bladder and IHBR dilation. The fluid filled gut of the worm was seen as a hyperintense stripe within its body [Figure - 3].

The patient was operated, a cholecystectomy and choledochotomy was done. One impacted worm was removed from the gall bladder neck and three worms removed on incising the CBD. The immediate postoperative period was uneventful. The left lobe abscess gradually disappeared as seen on serial usg.The T-tube cholangiograms performed subsequently revealed a normal biliary tree and no strictures or filling defects were seen.The patient recovered completely.

   Discussion Top

The incidence of Hepatobiliary Ascariasis (HBA) is probably underestimated [1]. The condition is closely linked to sanitation and thus common in the third world countries. IN some areas like Kashmir,it has been estimated to be as common as gall stone disease (34.8 %)[1]. In a sonographic study the prevalence of HBA in adult population has been estimated to be less than half a percent but may be more if other modalities of detection like duodenoscopy and stool examination were included.[2]

Ascaris has a propensity to explore small openings and when in the duodenum invades through the ampullary orifice to gain entry into the hepatobiliary system. They generally tend to move out of the ducts within a day or two after having caused symptoms a fact that has been recorded on duodenoscopy and serial ultrasounds.[2].Worms trapped in the ducts form a nidus for stone formation [2].

The clinical presentation of HBA depends on the presence of worms in the lumen or ductal system. Worms in the duodenum invading the ampullary orifice induce biliary colic or acute pancreatitis by blocking the bile duct or pancreatic duct respectively. Worms in the common and cystic duct caused gall bladder distension and acute cholecystitis. Khuroo et al having studied 500 symptomatic patients, all cases of HBA confirmed on usg, duodenoscopy or both found biliary colic (56%),acute cholangitis(24%) and acute cholecystitis (13%) as the predominant clinical presentation.[2] Less common were acute pancreatits (6%) and hepatic abscess(1%).

Usg is a non-invasive, cheap and accurate modality to diagnose and follow up cases of HBA. Khuroo et al have outlined several sonographic appearances of worms in the bile ducts [1],[2],[3]. Linear or curvilinear structures, single or multiple, with or without acoustic shadowing are typical for ascariasis [Figure - 4].Various signs have been described for ascariasis which include " spaghetti appearance", " bulls eye sign "and "impacted worm sign".[3],[4]. The 'inner tube" or the "double tube" signs imply the visualisaton of the hypoechoic alimentary canal seen within the round cross section of the worm [Figure - 5]. Movement of the worms has to be differentiated from that due to breathing and the worm movement is unrelated to changes in posture of the patient.

Dilation of the common bile duct with or without a distended gall bladder is the next common finding [1]. Other associated features are gall bladder wall edema, sludge in the gall bladder, edematous pancreas and liver abscesses.

Worms in the gall bladder lumen are less common but easily demonstrable on usg, as seen in our case [3].

Finally usg is also useful in confirming exit of the worms from the biliary tree and follow up as reinfection is common.

The disadvantage of usg is that it cannot visualize the more common duodenal ascariasis and thereby miss half the cases of HBA.[2]

CT -axial images and the coronal reformats can detect linear structures in the gall bladder neck,common bile duct and the ampullary area of the duodenum, structures that may not be easily accessible on usg. In transverse images the end-on appearance of the coiled worm forms two high density ring shaped structures described as two bull's eyes or as an eye glass.[5].

MRCP has the advantage of detecting worms in the duodenum and those across the papilla,and also in a minority of those in the main pancreatic duct. It confirms the findings of usg which are operator dependent and also gives a global view of the entire hepatobiliary system. These signs are seen in more detail on MRCP which can also reveal the hyperintense fluid in the gut of the ascariasis and thereby giving the worm a double tube appearance. Postprocessing of the MRCP source images provides an endoscopic view of the worm in the CBD. Although MRI is the superior imaging modality, it is not cost effective in developing countries where the incidence is very high. Therefore ultrasound alone may be sufficient to diagnose and treat HBA in most cases

   References Top

1.Khuroo MS,Zargar SA,Mahajan R,Bhat RL,Javid G.Sonographic appearances in biliary ascariasis.Gastroenterology1987;93:267-72.  Back to cited text no. 1  [PUBMED]  
2.Khuroo MS, Zargar SA,Mahajan R.Hepatobiliary and pancreatic ascariasis in India.Lancet 1990;335:1503-1506.  Back to cited text no. 2  [PUBMED]  
3.Khurro MS,Zargar SA,Yatoo GN, et al .Sonographic findings in gall bladder ascariasis.J clin ultrasound 1992;20:587-589.  Back to cited text no. 3    
4.Kubaska SM,Chew FS.Biliary Ascariasis.AJR 1997;169:492  Back to cited text no. 4  [PUBMED]  
5.Biliary ascariasis:CT,MR cholangiopancreatography and navigator endoscopic appearance -a report of a case of acute biliary obstruction.Abdom Imaging.1999 sep-Oct;34(3):136-138.  Back to cited text no. 5    

Correspondence Address:
A Suri
Radiologist, Command Hospital Air Force, Bangalore-560007
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]

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