Parasites and Biliary stones

Hepatolithiasis ٨٥
Hepatolithiasis
Primary intrahepatic lithiasis is an entity defined by intrahepatic
stones exclusively located in the intrahepatic ducts above the emergence
of the common bile duct. The disease is classified in two types: Eastern
type (stones formed primarily in intrahepatic ducts) and Western type
(stones formed in the extrahepatic bile system, usually in gallbladder,
which migrate up to the intra-hepatic ducts) (Pereira et al., 1994).
Hepatolithiasis appears mostly as brown pigment stones (calcium
bilirubinate stones) but contain more cholesterol in composition. The
disease is characterized by its intractable nature and frequent recurrence.
Moreover, the most unfavorable complication of the disease is an
intrahepatic cholangiocarcinoma (Shoda et al., 2003).
These stones are rough surfaced, ovoid or faceted in shape, brown-
to-orange in colour, soft and friable in consistency, and easily crushed to
form ‘biliary mud’. They usually number more than 10 in a single patient.
Microscopically, they consist of calcium salts of bilirubin, fatty acid and
cholesterol arranged in a glycoprotein matrix. Scanning electron
microscopy often reveals microcolonies of bacteria mixed with the
crystals (Strichartz et al, 1991).
Hepatolithiasis is associated with bile stasis and bacterial infection.
E coli were the most frequent isolate followed by Klebsiella,
Streptococcus (D), and pseudomonas. Beta-glucuronidase from E coli has
been thought to be responsible for the formation of calcium bilirubinate
stones by effecting hydrolysis of bilirubin glucuronide to free bilirubin,
which is insoluble in water. Bacteroides and Clostridium were the most
frequent isolates from the biliary tract and were shown to have beta-
glucuronidase activity. Anaerobes were often found together with