Parasites and Biliary stones

Relationship between clonorchis sinensis and biliary stones ٩٦
The diagnosis of clonorchiasis is confirmed by the presence of an
adult worm in duodenal aspirate or bile or the presence of ova in the
stool. Abdominal ultrasound and CT scanning demonstrate predominantly
intrahepatic biliary disease with diffuse dilatation and clubbing. Bile duct
fibrosis may be seen as increased echogenicity of ultrasound and
thickening on CT. Individual Clonorchis worms may produce an
echogenic focus without shadowing in the peripheral ducts, but in general
they are too small to be seen by non-invasive imaging. ERCP is useful in
the diagnosis of patients with jaundice. Four patterns have been observed:
Diffuse tapering of the intrahepatic ducts with dilatation indistinguishable
from that associated with extrahepatic obstruction; a solitary cyst similar
to a liver abscess cavity or retention cyst; multiple cystic dilatations of the
intrahepatic ducts, producing a mulberry-like appearance that is
characteristic of liver fluke infestation; and a combination of these
findings, with extensive cystic dilatation in some areas of the liver and
biliary duct ectasia in others (Goldman and Brandborg, 1996).
Cholangiography may also show a characteristic appearance of
Clonorchis worms as filling defects within the ductal system. Depending
on the projection, one of five patterns may appear on the cholangiogram:
filamentous, wavy, curled-up, elliptical wavy and elliptical-shaped filling
defects (Leung et al., 1989). Because of the location of the worms, the
diagnosis should be suspected if there is significant peripheral ductal
dilatation in the absence of extrahepatic ductal dilatation or stricture.
(Leung, 1997).