Parasites and Biliary stones

Gallbladder stones ٦٥
• Drugs: Estrogens increase cholesterol formation, which supersaturate
the bile, leading to precipitation of cholesterol stones (Lee, 2006).
Clofibrate and other fibrate hypolipidemic drugs increase hepatic
elimination of cholesterol via biliary secretion. Somatostatin analogs
appear to predispose to gallstones by decreasing gallbladder emptying
(Heuman, 2006).
Composition of cholesterol stones:
They have a protein matrix and although are composed
predominantly of cholesterol, they contain also bile pigments and
different amounts of calcium carbonate and palmitate. These calcium
salts are deposited on the periphery of the stones and their amounts
determines their radio density (Cuschieri et al., 2002).
(B) Black pigment gallstones:
Account for 20% of stones in the west although their prevalence is
higher in Asian countries (Apstein and Carey, 1993).
Risk factors:
Disorders of hemolysis associated with pigment gallstones include
sickle cell anemia, hereditary spherocytosis, and beta thalassemia. About
half of all cirrhotic patients have pigment gallstones, due to red cell
sequestration in enlarged spleen (Heuman, 2006).
Composition and characters of black pigment stones: They are
composed of bilirubin polymers without calcium palmitate, different
amounts of cholesterol (3-25%) and a matrix of organic materials. These
stones are usually multiple, small, irregular and dark green to black in
color (Schwartz, 2005).