The gallbladder sits below the liver and stores bile. Cholesterol or pigment stones, both commonly referred to as gallstones, can occur in the gallbladder. Gallstones affect more than 25 million people in the United States with almost 1 million new individuals affected each year, according to the American Gastroenterological Association. Gallstones are more common in females, individuals over the age of 60, pregnant women, and obese people. Gallstones can block the bile from leaving the gallbladder and can cause inflammation and pain for the affected individual.
Increased Cholesterol
One function of the liver is to excrete cholesterol, which is a type of fat found in the bloodstream. Bile from the liver also dissolves the excess cholesterol. Once too much cholesterol occurs in the bile, it begins to form solid crystals. The crystals start sticking together and cause a cholesterol stone to form, according to Merck Manuals. Cholesterol stones are usually yellow or green colored.
Increased Bilirubin
A function of the liver is to break down old red blood cells from the body. The byproduct of destroying the red blood cells is a chemical called bilirubin. Some medical conditions, such as cirrhosis of the liver or an infection of the biliary tract, can cause the liver to produce too much bilirubin, according to MayoClinic.com. The increased amounts of bilirubin in the bile can cause gallstones to form. The stones that form from excessive bilirubin are pigment stones. Pigment gallstones are either black or brown in color.
Gallbladder Malfunction
Conditions such as pregnancy may cause the gallbladder to not empty properly. When the gallbladder retains materials, the particles of different compounds, such as cholesterol and bilirubin, create a substance referred to as biliary sludge, according to the Merck Manuals. The biliary sludge can naturally resolve or can cause gallstones to form from the accumulated particles.
