The gallbladder is a small pear-shaped organ located beneath the liver on the right side of the abdomen. The gallbladder's primary functions are to store and concentrate bile and secrete bile into the small intestine at the proper time to help digest food.

The gallbladder is connected to the liver and the small intestine by a series of ducts, or tube-shaped structures, that carry bile. Collectively, the gallbladder and these ducts are called the biliary system.

Bile is a yellow-brown fluid produced by the liver. In addition to water, bile contains cholesterol, lipids (fats), bile salts (natural detergents that break up fat), and bilirubin (the bile pigment that gives bile and stools their color). The liver can produce as much as three cups of bile in 1 day, and at any one time, the gallbladder can store up to a cup of concentrated bile.

As food passes from the stomach into the small intestine, the gallbladder contracts and sends its stored bile into the small intestine through the common bile duct. Once in the small intestine, bile helps digest fats in foods. Under normal circumstances, most bile is recirculated in the digestive tract by being absorbed in the intestine and returning to the liver in the bloodstream.

Gallstones are pieces of solid material that form in the gallbladder. Gallstones form when substances in the bile, primarily cholesterol and bile pigments, form hard, crystal-like particles.

Cholesterol stones are usually white or yellow in color and account for about 80 percent of gallstones. They are made primarily of cholesterol.

Pigment stones are small, dark stones made of bilirubin and calcium salts that are found in bile. They account for the other 20 percent of gallstones. Risk factors for pigment stones include cirrhosis, biliary tract infections, and hereditary blood cell disorders, such as sickle cell anemia.

Gallstones vary in size and may be as small as a grain of sand or as large as a golf ball. The gallbladder may develop a single, often large, stone or many smaller ones, even several thousand.
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2) What Causes Gallstones?

Progress has been made in understanding the process of gallstone formation. Researchers believe that gallstones may be caused by a combination of factors, including inherited body chemistry, body weight, gallbladder motility (movement), and perhaps diet.

Cholesterol gallstones develop when bile contains too much cholesterol and not enough bile salts. Besides a high concentration of cholesterol, two other factors seem to be important in causing gallstones. The first is how often and how well the gallbladder contracts; incomplete and infrequent emptying of the gallbladder may cause the bile to become overconcentrated and contribute to gallstone formation. The second factor is the presence of proteins in the liver and bile that either promote or inhibit cholesterol crystallization into gallstones.

Other factors also seem to play a role in causing gallstones but how is not clear. Obesity has been shown to be a major risk factor for gallstones. A large clinical study showed that being even moderately overweight increases one's risk for developing gallstones. This is probably true because obesity tends to cause excess cholesterol in bile, low bile salts, and decreased gallbladder emptying. Very low calorie, rapid weight-loss diets, and prolonged fasting, seem to also cause gallstone formation.

In addition, increased levels of the hormone estrogen as a result of pregnancy, hormone therapy, or the use of birth control pills, may increase cholesterol levels in bile and also decrease gallbladder movement, resulting in gallstone formation.

No clear relationship has been proven between diet and gallstone formation. However, low-fiber, high-cholesterol diets, and diets high in starchy foods have been suggested as contributing to gallstone formation.
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3) Who Is at Risk for Gallstones?

This year, more than 1 million people in the United States will learn they have gallstones. They will join the estimated 20 million Americans--roughly 10 percent of the population--who already have gallstones.

• Women between 20 and 60 years of age. They are twice as likely to develop gallstones than men.
• Men and women over age 60.
• Pregnant women or women who have used birth control pills or estrogen replacement therapy.
• Native Americans. They have the highest prevalence of gallstones in the United States. A majority of Native American men have gallstones by age 60. Among the Pima Indians of Arizona, 70 percent of women have gallstones by age 30.
• Mexican-American men and women of all ages.
• Men and women who are overweight.
• People who go on "crash" diets or who lose a lot of weight quickly.

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4) What Are the Symptoms of Gallstones?

Most people with gallstones do not have symptoms. They have what are called silent stones. Studies show that most people with silent stones remain symptom free for years and require no treatment. Silent stones usually are detected during a routine medical checkup or examination for another illness.
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5) What Problems Can Occur?

A gallstone attack usually is marked by a steady, severe pain in the upper abdomen. Attacks may last only 20 or 30 minutes but more often they last for one to several hours. A gallstone attack may also cause pain in the back between the shoulder blades or in the right shoulder and may cause nausea or vomiting. Attacks may be separated by weeks, months, or even years. Once a true attack occurs, subsequent attacks are much more likely.

Sometimes gallstones may make their way out of the gallbladder and into the cystic duct, the channel through which bile travels from the gallbladder to the small intestine. If stones become lodged in the cystic duct and block the flow of bile, they can cause cholecystitis, an inflammation of the gallbladder. Blockage of the cystic duct is a common complication caused by gallstones.

A less common but more serious problem occurs if the gallstones become lodged in the bile ducts between the liver and the intestine. This condition can block bile flow from the gallbladder and liver, causing pain and jaundice. Gallstones may also interfere with the flow of digestive fluids secreted from the pancreas into the small intestine, leading to pancreatitis, an inflammation of the pancreas.

Prolonged blockage of any of these ducts can cause severe damage to the gallbladder, liver, or pancreas, which can be fatal. Warning signs include fever, jaundice, and persistent pain.
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6) How Are Gallstones Diagnosed?

Many times gallstones are detected during an abdominal x-ray, computerized axial tomography (CT) scan, or abdominal ultrasound that has been taken for an unrelated problem or complaint.

When actually looking for gallstones, the most common diagnostic tool is ultrasound. An ultrasound examination, also known as ultrasonography, uses sound waves. Pulses of sound waves are sent into the abdomen to create an image of the gallbladder. If stones are present, the sound waves will bounce off the stones, revealing their location.

Ultrasound has several advantages. It is a noninvasive technique, which means nothing is injected into or penetrates the body. Ultrasound is painless, has no known side effects, and does not involve radiation.
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7) How Are Gallstones Treated?

Surgery

Despite the development of nonsurgical techniques, gallbladder surgery, or cholecystectomy, is the most common method for treating gallstones. Each year more than 500,000 Americans have gallbladder surgery. Surgery options include the standard procedure, called open cholecystectomy, and a less invasive procedure, called laparoscopic cholecystectomy.

The standard cholecystectomy is a major abdominal surgery in which the surgeon removes the gallbladder through a 5-to 8-inch incision. Patients may remain in the hospital about a week and may require several additional weeks to recover at home.

Laparoscopic cholecystectomy is a new alternative procedure for gallbladder removal. Some 15,000 surgeons have received training in the technique since its introduction in the United States in 1988. Currently about 80 percent of cholecystectomies are performed using laparoscopes.

Laparoscopic cholecystectomy requires several small incisions in the abdomen to allow the insertion of surgical instruments and a small video camera. The camera sends a magnified image from inside the body to a video monitor, giving the surgeon a close-up view of the organs and tissues. The surgeon watches the monitor and performs the operation by manipulating the surgical instruments through separate small incisions. The gallbladder is identified and carefully separated from the liver and other structures. Finally, the cystic duct is cut and the gallbladder removed through one of the small incisions. This type of surgery requires meticulous surgical skill.

Laparoscopic cholecystectomy does not require the abdominal muscles to be cut, resulting in less pain, quicker healing, improved cosmetic results, and fewer complications such as infection. Recovery is usually only a night in the hospital and several days recuperation at home.

The most common complication with the new procedure is injury to the common bile duct, which connects the gallbladder and liver. An injured bile duct can leak bile and cause a painful and potentially dangerous infection. Many cases of minor injury to the common bile duct can be managed nonsurgically. Major injury to the bile duct, however, is a very serious problem and may require corrective surgery. At this time it is unclear whether these complications are more common following laparoscopic cholecystectomy than following standard cholecystectomy.

Complications such as abdominal adhesions and other problems that obscure vision are discovered during about 5 percent of laparoscopic surgeries, forcing surgeons to switch to the standard cholecystectomy for safe removal of the gallbladder.

Many surgeons believe that laparoscopic cholecystectomy soon will totally replace open cholecystectomy for routine gallbladder removals. Open cholecystectomy will probably remain the recommended approach for complicated cases.

A Consensus Development Conference panel, convened by the National Institutes of Health in September 1992, endorsed laparoscopic cholecystectomy as a safe and effective surgical treatment for gallbladder removal, equal in efficacy to the traditional open surgery. The panel noted, however, that laparoscopic cholecystectomy should be performed only by experienced surgeons and only on patients who have symptoms of gallstones.

In addition, the panel noted that the outcome of laparoscopic cholecystectomy is greatly influenced by the training, experience, skill, and judgment of the surgeon performing the procedure. Therefore, the panel recommended that strict guidelines be developed for training and granting credentials in laparoscopic surgery, determining competence, and monitoring quality. According to the panel, efforts should continue toward developing a noninvasive approach to gallstone treatment that will not only eliminate existing stones, but also prevent their formation or recurrence.
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In addition to surgery, nonsurgical approaches have been pursued but are used only in special situations and only for gallstones that are predominantly cholesterol.

Oral dissolution therapy with ursodiol (Actigallr) and chenodiol (Chenixr) works best for small, cholesterol gallstones. These medicines are made from the acid naturally found in bile. They most often are used in individuals who cannot tolerate surgery. Treatment may be required for months to years before gallstones are dissolved.

Mild diarrhea is a side effect of both drugs; chenodiol may also temporarily elevate the liver enzyme transaminase and mildly elevate blood cholesterol levels.

Two therapies, contact dissolution with methyltert butyl ether instillation through a catheter placed into the gallbladder and extracorporeal shock-wave lithotripsy (ESWL), are still experimental.

Each of these alternatives to gallbladder surgery leaves the gallbladder intact; so stone recurrence, which happens in about one-half the cases, is a major drawback.
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Additional Readings

Gupta, KL. Cholelithiasis: New options for diagnosis and treatment of its complications. Senior Patient 1991; 3(1): 42, 44-46. Article for health professionals explores new options for diagnosis of gallstones and treatment of complications.

Lewis, R. Gallbladder: an organ you can live without. FDA Consumer 1991; 25(4): 13-15. Article for a lay audience reviews current information about gallbladder function and disease.

Traverso, LW. Laparoscopic cholecystectomy. Practical Gastroenterology 1991; 15(4): 16, 21, 25-27. Article for health professionals discusses surgical technique of laparoscopic cholecystectomy.

Your gallstones: diagnosis and treatment, 1991. Digestive Disease National Coalition, 711 Second Street, NE, Suite 2, Washington, DC 20002; (202) 544-7497. Brochure outlines causes, diagnosis, and treatments of gallstones.

National Digestive Diseases Information Clearinghouse

2 INFORMATION WAY
BETHESDA, MD 20892-3570

NIH Publication No. 95-2897
March 1993