Parasites and Biliary stones

Relationship between Echinococcosis and biliary stones ٩٩
Relationship between fascioliasis and biliary
stones
Fascioliasis can be characterized by three distinct phases: Invasive
(acute) phase; latent phase, and chronic phase. The invasive phase
corresponds to the penetration and migration of the juvenile, immature
parasites through the liver parenchyma with the production of tissue
necrosis, acute inflammation and hemorrhage (Kayabali et al., 1992).
The invasive phase occurs during the first 3 months after ingestion of the
encysted metacercariae. After a period, healing takes place and evidence
of tissue destruction disappears completely (Dawes, 1963). The chronic
phase is established when the flukes gain access to the biliary system.
The fasciola produces biliary epithelial hyperplasia. Thickening and
dilatation of the ducts and the gallbladder wall occur. Other complications
of long standing fascioliasis in humans including portal and biliary
fibrosis, cirrhosis and portal hypertension (Rivero and Marcial, 1989).
However, the etiological relationship between fasciola infection and
cirrhosis is not clear (Jones et al., 1977).
Associated lithiasis of the bile ducts or of the gallbladder is frequent
(Chen and Mott 1990 and Wong et al., 1985). Eggs or fragments of
dead parasites may constitute the nucleus for calculi. Acute pancreatitis as
a complication of biliary fascioliasis has been reported (Maroy et al.,
1987). ERCP and sphincterotomy may be used to extract F. hepatica
parasites from the biliary tree (Veerappan et al., 1991).