Saturday, January 23, 2010

Oriental cholangitis - MRI

42 year old female came with history of recurrent attacks of abdominal pain, fever, and jaundice. MRCP coronal HASTE image of upper abdomen shows dilatation of intrahepatic biliary radicles and CBD with multiple calculi within the hepatic ducts (L>R) and CBD (arrows). No calculi in the gall bladder. Thick slab MRCP image (left) better shows the IHBR and CBD dilatation with hepaticolithiasis and choledocholithiasis. Incidentally note the right retrocaval ureter.

Recurrent pyogenic cholangitis (RPC) or Oriental cholangiohepatitis is a recurrent and chronic and biliary tract infectious process typically seen in the Asian population, particularly Chinese. The disease involves recurrent episodes of infectious cholangitis with fever, abdominal pain, and jaundice. The causative infectious agents are typically bacterial such as E. coli and other coliforms. However biliary tract parasites such as Ascaris lumbricoides and Clonorchis sinensis are common coexistent pathogens, and it is not clear which infectious agents are the primary cause or representative of secondary superinfection.
The recurrent infections lead to bile duct dilatation, strictures, obstruction, and calculi. The bile duct dilatation may be pronounced and involves both the intrahepatic and extrahepatic ducts. There is a predilection for ductal involvement in the left lobe of the liver but diffuse intrahepatic disease can be seen. The extrahepatic bile duct can be quite dilated up to as much as 3-4cm in diameter. The dilatation of the extrahepatic duct may be secondary to loss of elasticity of the duct wall due to chronic infection or it may be due to ampullary narrowing.
The calculi are typically bile pigment stones with varying amounts of calcium. The stones have a mud or paste-like consistency. The stones presumably form due to bacterial enzymes causing deconjugation of bilirubin which then precipitates as calcium bilirubinate. In addition it has been postulated that a low protein diet as is seen in some Asian populations may play a role in formation of intraductal stones. MRCP is gold standard non invasive investigation for diagnosis of oriental cholangitis.

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