From the Research
Brown gallstones are primarily composed of calcium bilirubinate, calcium fatty acid soaps, and other calcium salts, and one key pathophysiological mechanism that contributes to their formation is the infection of the biliary tree, leading to the hydrolysis of conjugated bilirubin and lecithin by bacterial enzymes. The composition of brown gallstones can vary, but they typically contain a mixture of calcium salts, including calcium bilirubinate, calcium palmitate, and calcium carbonate 1. The formation of brown gallstones is often associated with infection of the biliary tree, which can lead to the hydrolysis of conjugated bilirubin and lecithin by bacterial enzymes, resulting in the formation of insoluble calcium salts 2, 3.
Some key factors that contribute to the formation of brown gallstones include:
- Infection of the biliary tree with enteric bacteria
- Hydrolysis of conjugated bilirubin and lecithin by bacterial enzymes
- Formation of insoluble calcium salts, including calcium bilirubinate and calcium palmitate
- Stasis and anaerobic conditions in the biliary tree, which can promote the growth of bacteria and the formation of brown gallstones 1, 4.
It's worth noting that the evidence suggests that brown gallstones are distinct from black pigment stones and cholesterol stones, and have a unique composition and pathophysiological mechanism of formation 1, 4. The most recent and highest quality study on this topic is from 2012, which provides a comprehensive overview of the pathogenesis of pigment gallstones, including brown gallstones 1.