Endoscopic cholangiopancreatography in hepatic clonorchiasis--a follow-up study

Liver fluke eggs in bile duct brush cytology: An unexpected diagnosis during evaluation of a biliary stricture

Clonorchis sinensis, a liver fluke parasite, infects humans through ingestion of raw or undercooked fish, crabs, or crayfish in endemic areas where the parasite is found. Clonorchis sinensis infects the liver, gallbladder, and bile duct in humans, causing Clonorichiasis. Although the majority of patients are asymptomatic, long-lasting infections may cause severe disease. Without treatment, human infection may persist for the parasite's lifespan (25-30 years). Pathologic diagnosis can be challenging as sampling may demonstrate limited cellularity with minuscule eggs that may be overlooked. Here, we report a rare case of liver fluke eggs diagnosed in bile duct brush cytology.

Parasitic infestations of the biliary tract

Parasitic infestations of the biliary tract are a common cause of biliary obstruction in tropical countries and can lead to such serious complications as cholangitis and cholangiocarcinoma. Endoscopic therapy has helped in the management of biliary complications caused by these parasites. Ascaris lumbricoides organisms, which normally reside in the jejunum, are actively motile and can invade the papilla, thus migrating into the bile duct and causing biliary obstruction. Endoscopic retrograde cholangiopancreatography is a useful diagnostic tool with potential for therapeutic management of biliary ascariasis. Infestation with Clonorchis sinensis organisms can cause such complications as intrahepatic stones, recurrent pyogenic cholangitis, cirrhosis, cholelithiasis, pancreatitis, and cholangiocarcinoma. Opisthorchis viverrini, Opisthorchis felineus, and Dicrocoelium dendriticum are closely related to C. sinensis and can also cause serious biliary complications. Fascioliasis, caused by Fasciola hepatica and F. gigantica, is a zoonotic helminthiasis that can present as acute hepatic or chronic biliary tract infection. CT, MRI, and ultrasound guidance are useful imaging tools for identifying these parasites and their complications.

Endoscopic diagnosis and management of tropical parasitic infestations

Biliary parasitosis is one of the common causes of biliary obstruction in developing countries and can often be confused with stone disease. With increased worldwide travel and immigration, these conditions are not limited to the developing countries alone. Ascariasis, hydatid liver disease, clonorchiasis, and fascioliasis are the commonly encountered parasitic infestations of the biliary tract usually presenting with biliary colic or cholangitis. Endoscopy has an important role in the diagnosis and emergent management of these conditions and in elective endoscopic therapy of associated complications. Endoscopic sphincterotomy and bile ductal clearance, along with pharmacotherapy, are the mainstays of treatment.

Risk factors for biliary tract carcinogenesis

Cholangiocarcinoma has a worldwide distribution which accounts for about 10-15% of all cases of primary hepatobiliary malignancy. Although, in the majority of cases, no aetiological factor can be identified, a number of risk factors have been shown to be important in the development of cholangiocarcinoma; most of these factors share long standing inflammation and chronic injury of the biliary epithelium. Primary sclerosing cholangitis is an uncommon disease, characterized by stricturing, fibrosis and inflammation of the biliary tree which is closely associated with chronic inflammatory bowel disease, particularly ulcerative colitis. It is commonly associated with cholangiocarcinoma and between 10-20% of patients with primary sclerosing cholangitis will go on to develop a cholangiocarcinoma. The rare congenital fibropolycystic diseases of the biliary system are associated with increased risks of cholangiocarcinoma, particularly choledochal cysts and Caroli's disease. Choledochal cysts are associated with a 10% overall incidence of cholangiocarcinoma: there is a 1% cumulative risk which plateaus after 15-20 years. However, the risk is diminished in children who present under the age of 10 years where the over all risk is 0.7%. This compares with the 14% over all risk of patients presenting over the age of 20 years. In the Far East, other forms of chronic inflammation associated with cholangiocarcinoma include infestation with liver flukes. Clonorchis sinensis and Opisthorchis viverinni. Cholangiocarcinoma is also rarely seen in association with cirrhosis and has been weakly linked to hepatitis C infection.

Biliary papillary hyperplasia with clonorchiasis resembling cholangiocarcinoma

Infection by the liver fluke Clonorchis sinensis is very common in the Far East. It causes low grade inflammatory changes and proliferation in the biliary tree. Initially there is desquamation of the biliary epithelium, followed by hyperplasia and adenomatous proliferation. Cholangiocarcinomas are potential long term complications. We present a case of biliary papillary hyperplasia with clonorchiasis resembling cholangiocarcinoma in a 69-yr-old Korean man. Early recognition of biliary hyperplasia and treatment of Clonorchis sinensis is important to prevent development of cholangiocarcinoma, especially in the Far East.

Hepatolithiasis and biliary parasites

Hepatolithiasis, or the presence of intrahepatic stones, is prevalent in East Asia and is characterized by the finding of stones within the intrahepatic bile ducts proximal to the confluence of the right and left hepatic ducts. Bile stasis and bacterial infection have been incriminated as the major aetiopathogenic factors. Clinical features include recurrent pyogenic cholangitis, multiple liver abscesses, secondary biliary cirrhosis and cholangiocarcinoma. The goals of management include accurate localization of pathologies, control of biliary sepsis and the elimination of stones and stasis. Ultrasonography, computed tomography and direct cholangiography complement each other in defining the stones, strictures and degree of liver damage. Non-operative biliary decompression by endoscopy and interventional radiology is effective in controlling the infection, but surgery remains the mainstay for the treatment of stones and strictures. Intra-operative ultrasound and flexible choledochoscopy, combined with percutaneous transhepatic cholangioscopy and intraductal lithotripsy, facilitate stone removal. Balloon dilatation and biliary stenting serve to open the bile duct strictures. The creation of a hepaticocutaneous jejunostomy after conventional surgery allows atraumatic access to the biliary system for the removal of recurrent stones. The management of biliary parasites begins with conservative measures, including analgesics and anti-helminthic therapy. In refractory cases or patients with acute cholangitis, endoscopic biliary drainage and the extraction of worms may be necessary. Improvement in sanitation plays a crucial role in the epidemiological control of these biliary diseases.