Biliary obstruction is seen with
Liver (Biliary) Flukes
a. On the basis of their migratory pathway in humans, these infections may be divided into the Clonorchis and Fasciola groups
b. Infection with Clonorchis sinensis, the Chinese or oriental fluke.
c. Infection with any of these three species is established by ingestion of raw or inadequately cooked freshwater fish harboring metacercariae.
d. These organisms excyst in the duodenum, releasing larvae that travel through the ampulla of Vater and mature into adult worms in bile canaliculi.
e. Mature flukes are flat and elongated, measuring 1–2 cm in length. The hermaphroditic worms reproduce by releasing small operculated eggs, which pass with bile into the intestines and are voided with stools.
f. The life cycle is completed in the environment in specific freshwater snails (the first intermediate host) and encystment of metacercariae in freshwater fish.
g. Except for late sequelae, the exact clinical syndromes caused by clonorchiasis and opisthorchiasis are not well defined. Since most infected individuals harbor a low worm burden, many are asymptomatic.
h. Moderate to heavy infection may be associated with vague right-upper-quadrant pain. In contrast, chronic or repeated infection is associated with manifestations such as cholangitis, cholangiohepatitis, and biliary obstruction.