hepatic and biliary disorders
Cholelithiasis
Pathophysiology of Cholelithiasis
 is often a precursor of gallstones. It consists of calcium bilirubinate (a polymer of bilirubin), cholesterol microcrystals, and mucin. Sludge develops during gallbladder stasis, as occurs during pregnancy or use of total parenteral nutrition. Most sludge is asymptomatic and disappears when the primary condition resolves. Alternatively, sludge can evolve into gallstones or migrate into the biliary tract, obstructing the ducts and leading to biliary colic, Choledocholithiasis and Cholangitis , or There are several types of gallstones. 85% of gallstones in the Western world ( Pathophysiology reference ). For cholesterol gallstones to form, the following is required: Bile must be supersaturated with cholesterol. Normally, water-insoluble cholesterol is made water soluble by combining with bile salts and lecithin to form mixed micelles. Supersaturation of bile with cholesterol most commonly results from excessive cholesterol secretion (as occurs in Obesity or The excess cholesterol must precipitate from solution as solid microcrystals. Such precipitation in the gallbladder is accelerated by mucin, a glycoprotein, or other proteins in bile. The microcrystals must aggregate and grow. This process is facilitated by the binding effect of mucin forming a scaffold and by retention of microcrystals in the gallbladder with impaired contractility due to excess cholesterol in bile. are small, hard gallstones composed of calcium (Ca) bilirubinate and inorganic Ca salts (eg, Ca carbonate, Ca phosphate). Factors that accelerate stone development include Alcohol-Related Liver Disease , chronic hemolysis, and older age. Brown pigment stonesare soft and greasy, consisting of bilirubinate and fatty acids (Ca palmitate or stearate). They form during infection, inflammation, and parasitic infestation (eg, liver flukes in Asia). Gallstones grow at about 1 to 2 mm/year, taking 5 to 20 years before becoming large enough to cause problems. Most gallstones form within the gallbladder, but brown pigment stones form in the ducts. Gallstones may migrate to the bile duct after cholecystectomy or, particularly in the case of brown pigment stones, develop behind strictures as a result of stasis and infection. 1.European Association for the Study of the Liver (EASL): EASL Clinical Practice Guidelines on the prevention, diagnosis and treatment of gallstones.J Hepatol65(1):146-181, 2016. doi: 10.1016/j.jhep.2016.03.005 