Ascending Cholangitis

Published on 19/07/2015 by admin

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Last modified 19/07/2015

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 Dilation of intrahepatic ± extrahepatic ducts with abrupt cut off at site of obstruction

– Biliary dilatation may be central, diffuse, or segmental
image Bile duct wall thickening with hyperenhancement
image Intraductal purulent bile or pus: High density on CT, intermediate to low signal on T1 and T2WI MR
image Heterogeneous liver enhancement, which can be wedge-shaped, peribiliary, patchy, or diffuse
image Can be associated with liver abscesses (1/4 of cases) or portal vein thrombosis
• Ultrasound findings

image Dilatation, stenosis, and thickening of bile duct walls with intraluminal echogenic debris (purulent bile)

TOP DIFFERENTIAL DIAGNOSES

• Primary sclerosing cholangitis
• Recurrent pyogenic, AIDS-related, or chemotherapy-related cholangitis

PATHOLOGY

• Pathogenesis: Stone/stricture → obstruction → bile stasis → ↑ biliary pressure → infection
• Source of infection is usually bacteria from duodenum, which ascend biliary tree
• Obstruction due to gallstones accounts for 80% of cases
• Other common causes include biliary strictures (benign or malignant), recent intervention, and hepatobiliary surgery

CLINICAL ISSUES

• Treatment with broad spectrum parenteral antibiotics and biliary drainage (usually via ERCP)
• Patients classically present with Charcot triad (pain, fever, jaundice)
image
(Left) Coronal CECT in a patient with fever and leukocytosis after Whipple procedure shows the common bile duct anastomosed to the Roux limb with thickening and hyperenhancement of the bile duct wall image and adjacent free fluid image, characteristic of ascending cholangitis.

image
(Right) Coronal MRCP in a patient with markedly elevated liver function tests and leukocytosis shows intra- and extrahepatic biliary dilatation. Note the relatively low signal pus and infectious debris within the mid and distal common duct image.
image
(Left) Coronal CECT in a patient presenting with fever and hypotension demonstrates thickening and hyperenhancement of a dilated CBD image with a small amount of adjacent fluid image, suggesting ascending cholangitis.

image
(Right) Coronal NECT in the same patient demonstrates an obstructing stone image as the cause of the patient’s cholangitis.

TERMINOLOGY

Synonyms

• Bacterial cholangitis, acute cholangitis, suppurative cholangitis, biliary infection

Definitions

• Pyogenic infection of biliary tree as a result of biliary obstruction

IMAGING

General Features

• Best diagnostic clue

image Biliary ductal dilatation, often with an irregular branching pattern and bile duct wall thickening with hyperenhancement
• Location

image Dilation of intrahepatic ± extrahepatic ducts

CT Findings

• Dilation of intrahepatic ± extrahepatic ducts (depending on level of obstruction) with abrupt “cut-off” at site of obstruction

image Obstructing stone of variable density on CT depending on stone type

– Sensitivity of CT for stones is variable (25-90%) with roughly 1/4 of stones isoattenuating to bile
– Bull’s-eye sign: Rim of bile surrounding stone
– Meniscus sign at distal common bile duct (CBD) may suggest occult stone (even if stone is low density and not visible)
• High-density intraductal debris (purulent bile or pus)
• Concentric and diffuse bile duct wall thickening with hyperenhancement
• Heterogeneous hepatic parenchymal enhancement: Wedge-shaped, peribiliary, patchy, or diffuse

image May be more apparent on arterial phase imaging
• Can be associated with liver abscesses (1/4 of cases) or portal vein thrombosis

image Small abscesses may arise adjacent to biliary tree and may communicate with bile ducts

MR Findings

• Intrahepatic biliary dilatation almost always present ± extrahepatic ductal dilatation

image MRCP nicely demonstrates level of obstruction with abrupt cut-off of duct, as well as abnormal arborization and tapering of intrahepatic ducts
image Biliary dilatation may be central, diffuse, or segmental
• Presence of intermediate to low T2WI and intermediate T1WI signal purulent material (pus) within bile ducts

image Juxtaposed against normal T2 hyperintense and T1 hypointense bile
• Obstructing stones are low signal on T1WI and T2WI
• Bile duct walls appear thickened on T1WI and T2WI with progressive hyperenhancement of duct walls on T1WI C+

image Often outlined by high T2 signal periportal edema
• Diffusely heterogeneous hepatic parenchymal enhancement, which can be wedge-shaped, peribiliary, or patchy in distribution

image Abnormal enhancement most apparent in arterial and delayed phases
• Liver abscesses (1/4 of cases) and portal vein thrombosis are common complications

Fluoroscopic Findings

• Cholangiography

image Irregular, thickened bile duct wall with luminal narrowing
image Ductal stricture or radiolucent filling defect (stone) with obstruction and proximal ductal dilatation
image Abnormal arborization and tapering of intrahepatic ducts
image Intrahepatic bile ducts may show communication with hepatic abscesses

Ultrasonographic Findings

• Dilatation, stenosis, and thickening of bile duct walls
• Intraluminal echogenic material (purulent bile or pus)

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