Re: Color of Stones

Gallstones

Gallstones are made mainly of cholesterol, bilirubin and calcium salts, with smaller amounts of protein and other materials. The main types re as follows:

Black pigment stones, (bilirubin stones) consist of polymers of bilirubin, with large amounts of mucoprotein. Bilirubin is formed when red blood cells die and their hemoglobin is broken down in the liver. These stones usually contain less than 10% cholesterol and 30-60% unconjugated bilirubin by weight. Conjugation is the joining of molecules in a certain way. Unconjugated bilirubin is not water soluble, while conjugated bilirubin is water soluble. Stones that are more than 4% calcium by weight show up on an x-ray, which is about 50% of black pigment stones. They are common in people with cirrhosis and chronic red blood cell conditions, such as the thalassemias and possibly sickle cell anemia, in which bilirubin excretion is increased.

Brown pigment stones are made of calcium salts of unconjugated bilirubin, with variable amounts of protein and cholesterol. They are usually primary biliary stones and are usually associated with biliary infection. Bacteria in the biliary system release products, which modify bilirubin precipitating as its calcium salt. They are more prevalent in Asians. It is associated with decreased secretory immunoglobulin which can make us more susceptible to infection and may be a fundamental cause of asthma, autoimmune conditions, Coeliac Disease, chronic infections, Crohn's Disease, candidiasis, food intolerances , allergies, autism and other behavioural problems. Very high levels of sIgA can also be found in people who have chronic infections and whose immune system is overloaded or hypersensitive. Lifestyle, stress and nutritional factors can all influence levels.

Cholesterol stones are the majority, 75-80% of Gallstones and are classified as cholesterol (non-pigmented) stones. Almost all cholesterol stones don’t show on x-rays. Cholesterol is the major component (usually greater than 70% by weight). Cholesterol-saturated bile is a prerequisite for the formation of cholesterol gallstones. People with Gallstones have a smaller pool of bile acid than similar people without stones.

Primary bile duct stones are stones formed in the biliary tree as the result of bile stasis either above a constriction, around a solid material or in association with infection. They are often earthy, muddy stones that can reach very large dimensions, and are composed predominantly of calcium bilirubinate and minor amounts of cholesterol or fatty acids. These stones do not dissolve well in lipid solvents and may be found in the bile ducts inside or outside the liver.

Secondary bile duct stones are found in the bile ducts in association with gallbladder stones, either having migrated out of the gallbladder or having formed concomitantly in the bile ducts. Their matrix reflects the composition of gallbladder stones, i.e. predominantly cholesterol in 80%, and black pigment in 20% of cases. The cause of black pigment stones are unknown, but may be associated with chronic red blood cell conditions or cirrhosis. Bacterial infection is not thought to be important in the development of either type of secondary stones.
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