Parasites and Biliary stones

Hepatolithiasis ٨٦
aerobes, suggesting the possibility of a synergistic effect that may
influence the occurrence and development of cholangitis, which is often
associated with hepatolithiasis. when an infection of the biliary tract
occurs the route by which bacteria reach the region is thought to be
hematogenous, lymphatic, or direct intraluminal ascending infection
(Tabata and Nakayama, 1984).
Biliary infestation by Clonorchis sinensis and Ascaris lumbricoides
leads to inflammation of the biliary epithelium, enhancing mucin
secretion and providing a nidus for stone formation together with
fragments of parasites and/or their eggs (Chen et al., 1984).
Recent investigations indicate that intrahepatic stone formation is
based upon the dual defects of up-regulation of cholesterol synthesis and
down-regulation of bile-acid synthesis in the liver, possibly in association
with defective secretion of phospholipid by its canalicular transporter,
(Shoda et al., 2006). Also, the anatomical changes of the intrahepatic
ducts, metabolic disorders, infections, idiopathic alteration. All these
factors may facilitate biliary stasis leading to stone formation (Pereira et
al., 1994).
Congenital and acquired risk factors:
Anatomical anomaly with branching of the right segmental bile
ducts from the left hepatic duct with is possibly associated with left
intrahepatic stone formation. Congenital choledochal dilatation, including
choledochal cyst, has relationship to intrahepatic stones. In contrast,
haemolytic diseases lead to bilirubin overproduction; this is associated
with pigment stones regardless of stone location with intrahepatic,
extrahepatic, common bile duct and/or gallbladder. Also less common
causes of bile stasis include Caroli’s disease (Hamlyn et al., 1976 and
Mercadier et al., 1984) which is a rare congenital condition