In this condition factsheet:
The Facts on Gallstones
Gallstones are crystal-like masses that typically form in the gallbladder. The gallbladder is a small organ located on the right side of the abdomen, just below the liver. The gallbladder's main function is to store bile (made by the liver) and secrete it into the small intestine to help digestion. Bile is made of water, cholesterol, fats, bile salts (natural detergents that break up fat), and a pigment called bilirubin. Gallstones form if the bile contains too much cholesterol, bile salts, or bilirubin.
There are two types of gallstones. Cholesterol stones contain mostly hardened cholesterol and account for approximately 80% of gallstones. Pigment stones are made of bilirubin and account for the other 20%. Gallstones can range in size from very small to as large as a golf ball. The gallbladder may develop any number and size of stones.
Gallstones are more common in women and people who are older, as well as in certain groups of people, such as people of First Nations descent and people who are overweight. In the United States, 20% of people over the age of 65 have gallstones, but most never experience symptoms. However, complications from gallstones can be serious if symptomatic stones are left untreated.
Causes of Gallstones
Medical understanding of how gallstones develop is increasing. It's believed that gallstones may be caused by a combination of factors including heredity, obesity, and the ability of the gallbladder to contract (motility).
Cholesterol gallstones form when there's too much cholesterol in the bile and not enough bile salts. Problems with the gallbladder's motility may cause the bile to become too concentrated and lead to stone formation.
The cause of pigment stones is uncertain. They tend to develop in people with pre-existing conditions such as cirrhosis, biliary tract infections, and hereditary blood disorders such as sickle cell anemia.
Risk factors that may lead to the formation of gallstones include:
- gender - women between 20 and 60 years of age are twice as likely to develop gallstones as men
- age - people over the age of 60
- estrogen - women who are pregnant or using hormone replacement therapy (HRT) or birth control pills
- obesity - a large clinical study showed that being even moderately overweight increases the risk for gallstone formation
- ethnicity - some ethnic groups have a higher prevalence of gallstones
- certain cholesterol-lowering medications - these medications lower cholesterol in the blood but lead to an increase in the amount of cholesterol secreted in bile
- diabetes - people with diabetes generally have high levels of fatty acids called triglycerides which increase the risk of gallstones
- rapid weight loss - this causes the liver to secrete extra cholesterol into the bile
- fasting - this inhibits the gallbladder's ability to contract, causing high concentrations of cholesterol to build up in the bile
- a diet high in fat and sugar along with an inactive lifestyle - this sets the stage for increased risk for gallstones
Symptoms and Complications of Gallstones
Most people with gallstones don't have symptoms. Gallstones in these cases are known as silent stones. They're sometimes detected during tests for an unrelated condition and usually don't need to be treated.
Problems arise when a gallstone attack occurs. Attacks may occur over a period of weeks, months or even years. However, once a full attack occurs, subsequent attacks are more likely. One attack may last from 20 minutes to several hours. Symptoms of an attack include:
- persistent, severe pain in the upper middle or upper right abdomen that increases rapidly
- pain in the back between the shoulder blades
- pain under the right shoulder
- nausea and vomiting
Other signs and symptoms of gallstones may be vague and non-specific.
The gallbladder is attached to the liver and small intestine by a series of tubes called ducts. Complications can occur if gallstones block the flow of bile by lodging in any of the ducts that carry the bile from the liver and gallbladder to the small intestine. Trapped gallstones may lead to gallbladder inflammation (cholecystitis) and duct inflammation (cholangitis). Gallstones may also become trapped in the pancreatic duct, which can cause painful inflammation (pancreatitis).
Beware of symptoms such as jaundice (yellowing of the skin and whites of the eyes), fever, clay-coloured stools, tea- or coffee-coloured urine, and persistent pain.