Gallstones are solidified, stone-like accumulations of variable size composed of either excess cholesterol or excess bilirubin in the blood. Gallstones form when bile stored in the gallbladder hardens during digestion. Bile, a substance that helps to digest fats in the body, is made by the liver and then stored in the gallbladder until the body needs it. When the body accesses bile, the gallbladder contracts and releases bile into a tube called the common bile duct. The common bile duct moves bile into the small intestine.
Bile is made up of water, fats, bile salts, cholesterol, proteins, and bilirubin, which is a waste product. Bile salts break up fat and bilirubin gives bile and stool its yellowish-brown color. If liquid bile contains too much cholesterol, bile salts, or bilirubin, it may harden into gallstones.
There are two types of gallstones: cholesterol stones and pigment stones. Cholesterol stones are usually yellow-green and account for about 80% of all gallstones. Pigment stones are small, dark stones made of bilirubin. Sizes vary from that of a grain of sand to the size a golf ball. One very large stone or many smaller stones, or even a combination of the two, may be present.
Why it is Problematic
Gallstones can block the normal flow of bile if they move from the gallbladder and lodge in bile ducts. Trapped bile in any of the ducts can cause inflammation in the gallbladder, the ducts, or, in rare cases, the liver. Sometimes when a gallstone passes through the common bile duct it provokes a pancreatic inflammation called gallstone pancreatitis, an extremely painful and potentially dangerous condition. Gallstones and gallstone "attacks" often cause extreme pain and discomfort.
Causes and Risk Factors
The precise cause of gallstones is unknown. Experts believe that cholesterol stones are a result of a buildup of cholesterol in the blood, whereas pigment stones may be the result of too much bilirubin, an insufficient amount of bile salts, or incomplete or incorrect emptying of the gallbladder.
- Pigment stones often develop in individuals with cirrhosis, biliary tract infections or hereditary blood disorders such as sickle cell anemia, all of which causes the liver to produce too much bilirubin.
- The presence of a gallstone can provoke the formation of more stones.
- Gallstones run in families.
- Women are twice as likely as men to have gallstones; this is thought to be a result of the incidence of excess estrogen during pregnancy, hormonal contraceptive use, or hormone replacement therapy.
- Weight plays a factor in developing gallstones: being moderately overweight increases the risk and obesity is a major contributing risk factor. Rapidly losing weight through crash dieting or fasting can cause gallstones.
- Diets high in fat or cholesterol and low in fiber increase the risk of developing gallstones.
- Individuals over the age of 60 are more likely to have gallstones.
- Native Americans have a genetic disposition to gallstones because of naturally higher levels of cholesterol in the bile. Most have had gallstone treatment by the time they reach 60 years of age. Members of the Pima tribe of Arizona are especially afflicted with gallstones, with 70% of all individuals experiencing gallstones by the age of 30.
- Individuals with diabetes generally have higher levels of fatty acids called triglycerides. Fatty acids may increase the risk of gallstones.
- Medications used to treat cholesterol levels reduce the amount of excreted cholesterol in bile, which can contribute to gallstones.
- Fever, even low-grade, or chills
- Jaundice (the yellowing of the skin or whites of the eyes)
- Stool that is light in color
- Pain that lasts longer than 5 hours
As a gallstone moves into bile ducts and creates a blockage, pressure increases in the gallbladder and one or more symptoms may appear. This is sometimes called a gallbladder attack, because it happens suddenly, sometimes following a fatty meal, and may wake an individual from sleep.
Symptoms of a gallbladder attack may include steady pain in the abdomen that increases rapidly and lasts anywhere from 30 minutes to several hours; this pain may be accompanied by pain in the back, between the shoulder blades.
Symptoms that are considered serious are:
If you are experiencing any two of these symptoms of a gallbladder attack, it is important to contact your doctor.
Many people pass gallstones without realizing it. These stones are sometimes referred to as "silent stones" because they cause no noticeable symptoms.
Without symptoms, gallstones are not dangerous and do not require treatment. Gallstones themselves do not interfere with any body organs.
Gallstones are frequently discovered during tests for another condition.
Generally, an ultrasound is considered the most specific and sensitive test for detecting gallstones. Other diagnostic imaging tests that can be used for the detection of gallstones include CT scan and a cholescintigraphy (HIDA scan) which requires an injection with nontoxic radioactive material that is absorbed by the gallstones. This test is used to detect abnormal contraction of the gallbladder or bile duct obstruction.
Endoscopic retrograde cholangiopancreatography (ERCP) is a method that is sometimes used in the diagnosis of gallstones. This procedure entails a tube with a camera being inserted down the throat and into the stomach and small intestine. A special dye is injected to make bile ducts more visible, and the gallstone is captured and removed by the endoscope.
Blood tests can be administered to monitor for infection, obstruction, pancreatitis, or jaundice.
Symptoms are similar to those indicating other conditions, making an accurate diagnosis from a doctor very important.
Treatment and Prevention
There is typically no treatment necessary for asymptomatic gallstones.
If an individual suffers from frequent attacks, a doctor may recommend a gallbladder removal operation called a cholecystectomy.
The gallbladder is a nonessential organ, and gallbladder removal is one of the most common surgeries in the U.S. People can live without a gallbladder because the liver produces enough bile to permit the body to digest a normal diet. Once the gallbladder is removed, bile flows from the liver directly into the small intestine instead of being stored in the gallbladder. About 1% of those who have had their gallbladder removed report having more frequent and softer stools.
Almost all gallbladder removal surgeries are performed via a minimally invasive procedure called a laparoscopy. In a laparoscopy, with the patient sedated, a surgeon makes a series of tiny incisions in the abdomen and inserts a laparoscope with a video camera to give a close-up view to the surgeon. The surgeon carefully separates the gallbladder and removes it via the tiny incision.
This procedure typically requires only one night's recovery in the hospital, and the patient may resume normal activity in one week, after a few days of bed rest. The benefits of a laparoscopy are that it is less painful and requires less recovery time than does an "open" surgery.
Open surgery is usually performed only when severe inflammation is present in the gallbladder. This type of surgery entails a longer incision, about 5-8 inches. Recovery for open gallbladder surgery is also longer, requiring 3-5 days in the hospital and several weeks at home. This method of surgery is only necessary in about 5% of those who have gallbladder removal surgery.
Nonsurgical cholesterol gallstone removal may be recommended in special circumstances or when another serious medical condition is present. Gallstones will usually recur within 5 years in patients treated with nonsurgical procedures.
Oral dissolution therapy is medication made from bile acid to dissolve gallstones. This treatment may take many months, or even years, to work. Oral dissolution therapy also causes side effects such as diarrhea and may raise the body's temperature as well as levels of liver enzyme (transaminase) and blood cholesterol.
Contact dissolution therapy entails the injection of a drug directly into the gallbladder to dissolve gallstones in 1-3 days.
Most people who have gallstones are not aware that they have them. Approximately 10-15% of all adults in the U.S. have gallstones, with about one million new cases reported each year.
There are about 800,000 gallbladder removal operations every year, making gallstones the most common gastrointestinal disorder requiring hospitalization and costing approximately 5 billion dollars per year nationally.