Gallstones: species and their composition

It is accepted to distinguish cholesterol stones, brown and black pigmentary gallstones.

[1], [2], [3], [4], [5], [6], [7]

Cholesterol Gallstones

Cholesterol stones - the most common type of gallstones - consist of either cholesterol alone or it is the main constituent of calculi. Gallstones consisting only of cholesterol, usually large in size, white in color or with a yellowish tinge, soft, easily crumbled, the bowls have a layered structure. Microscopically pure cholesterol stones are represented by a set of thin long monohydrate crystals of cholesterol that are connected together by mucin-glycoproteins with dark fibers consisting of calcium salts of unconjugated bilirubin

Mixed cholesterol stones contain more than 50% cholesterol and occur somewhat more often than pure cholesterol. They, as a rule, are smaller and the cups are plural.

[8], [9], [10], [11], [12], [13], [14],

Pigmentary gallstones

Pigmental stones account for 10-25% of all gallstones in patients in Europe and the US, but among the population of Asian countries their frequency is much higher. As in the case of cholesterol stones, pigmented stones are more common in women, and they are usually small, fragile, black or dark brown in color, their frequency increases with age.

Black pigmented stones

Black pigmented stones consist of either a black polymer - calcium bilirubinate, or from polymer-like compounds of calcium, copper, a large number of mucin-glycoproteins. Do not contain cholesterol. In stones, it is not possible to reveal a clear crystalline structure. They are more often found in patients with cirrhosis of the liver, with chronic hemolytic conditions (hereditary spherocytic or sickle cell anemia, vascular prosthesis, artificial heart valves, etc.). About 20-25% of the gall bladder stones make up, they can migrate to the bile ducts.

In the mechanism of formation of black pigment stones, a certain role is assigned to the supersaturation of bile with unconjugated bilirubin and a change in its pH.

[15], [16], [17], [18]

Brown pigmented stones

Brown pigmented stones consist mainly of calcium salts of unconjugated bilirubin (calcium bilirubin, polymerized less than in black pigmented stones) with the inclusion of different amounts of cholesterol and protein. The formation of brown pigmented stones is associated with the presence of infection (cholecystitis, ascending cholangitis), microscopic examination reveals cytoskeleton bacteria. Stones can form in the gallbladder and in the ducts, and in the latter they are formed more often than stones of another composition. In recent decades, a decrease in the frequency of pigmentary gallstones has been noted, which many researchers attribute to a decrease in the level of infectious diseases of the biliary tract.

In the mechanism of stone formation, great importance is attached to the hydrolysis of bilirubin glucuronide already in the bile ducts under the action of beta-glucoronidase bacteria with the subsequent precipitation of bilirubin.

[19], [20], [21], [22], [23]

Formation of pigmented stones

Black pigmented stones, as a rule, are formed in the gallbladder of patients with cirrhosis of the liver (up to 30% of observations), chronic hemolysis, chronic pancreatitis. The structure of concrements primarily includes calcium bilirubin, calcium carbonate, calcium phosphate, mucin-glycoprotein (up to 20% of weight), etc.

As is known, bilirubin is a hydrophobic (insoluble in water) and potentially toxic substance that circulates in the plasma in a closely bound albumin and can not be excreted in the urine. The ability of the body to remove bilirubin is associated with the removal of it from the blood plasma by the hepatic cell by conjugation with glucuronic acid and the subsequent splitting into the bile of a water-soluble compound-bound or direct bilirubin (bilirubin diglucuronide, bilirubin monoglucuronide). The unifying factor predisposing to the formation of the first pigmented stones is the increased secretion of bilirubin compounds (especially bilirubin monoglyuku ronida) in the bile. For example, with hemolysis, the release of bilirubin compounds into the bile can increase in 10-fold size.

As a result of a violation of acidification in the gallbladder (for example, with its inflammation), bile supersaturation with carbonate and calcium phosphate arises, which does not occur in acid medium and that in turn facilitates the precipitation of bilirubin compounds and subsequent stone formation. It is important to note that patients with black gallstones have no violations of the motor function of the gallbladder.

It is believed that the formation of brown pigmented stones is the result of an anaerobic infection, while bacterial cytoskeleton is found in the calculi. The presence of biliary stasis can facilitate bacterial infection, the accumulation of mucus and bacterial cytoskeleton in the ducts. Under the action of enzymes produced by enterobacteria, unbound bilirubin ß-glucuronidase), unconjugated bile acids (acid hydrolase), and palmitic and stearic acid (phosphatase A) from phospholipids are produced.

The anionic products of the described enzymatic process can bind to calcium, forming insoluble calcium salts and leading to the formation of gallstones.

[24], [25], [26], [27],