Gallstones are hard deposits that form inside the gallbladder. These may be as small as a grain of sand or as large as a golf ball.
The cause of gallstones varies.
There are two main types of gallstones:
• Stones made of cholesterol — This is the most common type. Cholesterol gallstones are not related to cholesterol level in the blood. In most cases, they are not visible on CT scans.
• Stones made of bilirubin — These are called pigment stones. They occur when red blood cells are destroyed and too much bilirubin is in the bile.
Gallstones are more common in:
• Female sex
• Native Americans and people of Hispanic descent
• People over age 40
• People who are overweight
• People with family history of gallstones
The following factors also make you more likely to develop gallstones:
• Bone marrow or solid organ transplant
• Failure of the gallbladder to empty bile properly (this is more likely to happen during pregnancy)
• Liver cirrhosis and biliary tract infections (pigmented stones)
• Medical conditions that cause too many red blood cells to be destroyed
• Rapid weight loss from eating a very low-calorie diet, or after weight loss surgery
• Receiving nutrition through a vein for a long period of time (intravenous feedings)
• Taking birth control pills