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What are gallstones?

Gallstones are small, pebble-like substances that develop in the gallbladder. The gallbladder is a small, pear-shaped sac located below your liver in the right upper abdomen. Gallstones form when liquid stored in the gallbladder hardens into pieces of stone-like material. The liquid—called bile—helps the body digest fats. Bile is made in the liver, then stored in the gallbladder until the body needs it. The gallbladder contracts and pushes the bile into a tube—called the common bile duct—that carries it to the small intestine, where it helps with digestion.

Bile contains water, cholesterol, fats, bile salts, proteins, and bilirubin—a waste product. Bile salts break up fat, and bilirubin gives bile and stool a yellowish-brown color. If the liquid bile contains too much cholesterol, bile salts, or bilirubin, it can harden into gallstones.

The two types of gallstones are cholesterol stones and pigment stones. Cholesterol stones are usually yellow-green and are made primarily of hardened cholesterol. They account for about 80 percent of gallstones. Pigment stones are small, dark stones made of bilirubin. Gallstones can be as small as a grain of sand or as large as a golf ball. The gallbladder can develop just one large stone, hundreds of tiny stones, or a combination of the two.

The gallbladder and the ducts that carry bile and other digestive enzymes from the liver, gallbladder, and pancreas to the small intestine are called the biliary system.

Gallstones can block the normal flow of bile if they move from the gallbladder and lodge in any of the ducts that carry bile from the liver to the small intestine. The ducts include the

  • Hepatic ducts, which carry bile out of the liver
  • Cystic duct, which takes bile to and from the gallbladder
  • Ccommon bile duct, which takes bile from the cystic and hepatic ducts to the small intestine

Bile trapped in these ducts can cause inflammation in the gallbladder, the ducts, or in rare cases, the liver. The pancreas can also be affected by gallstones. The pancreas drains chemicals that help digest food through the pancreatic duct. The common bile duct and the pancreatic duct drain through the same opening into the small intestine. Sometimes gallstones passing down the common bile duct can block the pancreatic duct. This provokes inflammation in the pancreas—called gallstone pancreatitis—an extremely painful and potentially dangerous condition.

If any of the bile ducts remain blocked for a significant period of time, severe damage or infection can occur in the gallbladder, liver, or pancreas. Left untreated, the condition can be fatal. Warning signs of a serious problem are fever, jaundice, and severe pain in the right upper abdomen.


What causes gallstones?

Scientists believe cholesterol stones form when bile contains too much cholesterol, too much bilirubin, or not enough bile salts, or when the gallbladder does not empty completely or often enough. The reason these imbalances occur is not known.

The cause of pigment stones is not fully understood. The stones tend to develop in people who have liver cirrhosis, biliary tract infections, or hereditary blood disorders—such as sickle cell anemia—in which the liver makes too much bilirubin.

Other factors that contribute to the formation of gallstones, particularly cholesterol stones, include…

  • Sex. Women are twice as likely as men to develop gallstones. Excess estrogen from pregnancy, hormone replacement therapy, and birth control pills appears to increase cholesterol levels in bile and decrease gallbladder movement, which can lead to gallstones.
  • Family history. Gallstones often run in families, pointing to a possible genetic link.
  • Weight. Being even moderately overweight increases the risk for developing gallstones. The most likely reason is that the amount of bile salts in bile is reduced, resulting in more cholesterol. Obesity is a major risk factor for gallstones, especially in women.
  • Diet. Diets high in fat and cholesterol and low in fiber increase the risk of gallstones due to increased cholesterol in the bile and reduced gallbladder emptying.
  • Rapid weight loss. As the body metabolizes fat during prolonged fasting and rapid weight loss—such as “crash diets”—the liver secretes extra cholesterol into bile, which can cause gallstones. In addition, the gallbladder does not empty properly.
  • Age. People older than age 60 are more likely to develop gallstones than younger people. As people age, the body tends to secrete more cholesterol into bile.
  • Ethnicity. American Indians have a genetic predisposition to secrete high levels of cholesterol in bile. In fact, they have the highest rate of gallstones in the United States. The majority of American Indian 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 also have high rates of gallstones.
  • Cholesterol-lowering drugs. Drugs that lower cholesterol levels in the blood actually increase the amount of cholesterol secreted into bile. In turn, the risk of gallstones increases.
  • Diabetes. People with diabetes generally have high levels of fatty acids called triglycerides. These fatty acids may increase the risk of gallstones


Who is at risk for gallstones?

People at risk for gallstones include:

  • Women—especially women who are pregnant, use hormone replacement therapy, or take birth control pills
  • People over age 60
  • American Indians
  • Mexican Americans
  • Overweight or obese men and women
  • People who fast or lose a lot of weight quickly
  • People with a family history of gallstones
  • People with diabetes
  • People who take cholesterol-lowering drugs


What are the symptoms of gallstones?

Gallstones can move into the cystic duct or the bile ducts and create a blockage. Pressure increases behind the stone and one or more symptoms may occur. Symptoms of blocked bile ducts are often called a gallbladder “attack” because they occur suddenly. Gallbladder attacks often follow fatty meals, and they may occur during the night. A typical attack can cause

  • Steady pain in the right upper abdomen that increases rapidly and lasts from 30 minutes to several hours
  • Pain in the back between the shoulder blades
  • Pain under the right shoulder
  • Nausea
  • Low grade fever
  • Yellow jaundice

Notify your doctor if you think you have experienced a gallbladder attack. Although these attacks often pass as gallstones move, your gallbladder can become infected and rupture if a blockage remains.

Many people with gallstones have no symptoms; these gallstones are called “silent stones.” They do not interfere with gallbladder, liver, or pancreas function and do not need treatment.


How are gallstones diagnosed?

Frequently, gallstones are discovered during tests for other health conditions. When gallstones are suspected to be the cause of symptoms, the doctor is likely to order one or many of the following exams.

  • Abdominal ultrasound. A handheld device, which a technician glides over the abdomen, sends sound waves toward the gallbladder. The sound waves bounce off the gallbladder, liver, and other organs, and their echoes make electrical impulses that create a picture on a video monitor. If gallstones are present, the sound waves will bounce off them, too, showing their location. Abdominal ultrasound is one of the most sensitive and specific tests for gallstones.
  • Cholescintigraphy (HIDA scan). The patient is injected with a small amount of nonharmful radioactive material that is normally mixes with the bile secreted by the liver. On a normal study the radioactive substance enters the gallbladder and is secreted in to the duodenum. Failure of the substance to pass in to the gallbladder or the duodenum suggests obstruction of the cystic duct or bile duct, respectively.
  • Magnetic Resonance Imaging (MRI). A large magnet creates very sophisticated cross-section images of the body. This test is noninvasive and uses no radiation. An special type of MRI called an MRCP is extremely sensitive for diagnosing stones in the common bile duct and pancreatic duct.
  • Endoscopic Ultrasound (EUS). With the patient sedated, a thin, flexible, lighted tube called an endoscope is passed though the mouth down into the small intestine. This special endoscope has an ultrasound probe on its tip allowing the doctor to examine the common bile duct through the wall of the small intestine. EUS has proven to be as sensitive as MRCP at diagnosing stones in the common bile duct. ERCP can often be performed during the same procedure to remove the stone.
  • Blood tests. Blood tests may be performed to look for signs of infection, obstruction, pancreatitis, or jaundice.

Because gallstone symptoms may be similar to those of a heart attack, appendicitis, ulcers, irritable bowel syndrome, hiatal hernia, pancreatitis, and hepatitis, an accurate diagnosis is important.


How are gallstones treated?

ERCP (Endoscopic Retrograde Cholangiopancreatography)

When imaging studies demonstrate gallstones within the common bile duct or blood work strongly suggests it, an ERCP is typically performed to remove the stone. With the patient sedated, a special endoscope is passed through the mouth down to the small intestine. The site where the common bile duct enters the small intestine is identified and a small catheter, or plastic tube, is inserted. Contrast material is injected and x rays are taken. The stones are clearly outlined as the contrast fills around them. To remove the stones a small incision through a sphincter, or circular muscle, is made at the bottom of the bile duct. This allows more room for the stone to pass. A balloon on the tip of the catheter above the stone is then inflated and the stone is dragged out into the intestine. Larger stones, that can not be simply dragged out, occasional have to captured in a small basket and crushed. The smaller fragments can then be sweep out of the bile duct. ERCP is often done as an outpatient procedure. Occasionally the patient is keep over night for observation. The risks of ERCP included bleeding, infection, and pancreatitis.

Gallstones within the gallbladder not causing symptoms, do not require treatment. If you are having frequent gallbladder attacks, or passing stones in to the common bile duct your doctor will likely recommend you have your gallbladder removed—an operation called a cholecystectomy. Surgery to remove the gallbladder—a nonessential organ—is one of the most common surgeries performed on adults in the United States.

Nearly all cholecystectomies are performed with laparoscopy. After giving you medication to sedate you, the surgeon makes several tiny incisions in the abdomen and inserts a laparoscope and a miniature 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. While watching the monitor, the surgeon uses the instruments to carefully separate the gallbladder from the liver, bile ducts, and other structures. Then the surgeon cuts the cystic duct and removes the gallbladder through one of the small incisions.

Recovery after laparoscopic surgery usually involves only one night in the hospital, and normal activity can be resumed after a few days at home. Because the abdominal muscles are not cut during laparoscopic surgery, patients have less pain and fewer complications than after “open” surgery, which requires a 5- to 8-inch incision across the abdomen.

If tests show the gallbladder has severe inflammation, infection, or scarring from other operations, the surgeon may perform open surgery to remove the gallbladder. In some cases, open surgery is planned; however, sometimes these problems are discovered during the laparoscopy and the surgeon must make a larger incision. Recovery from open surgery usually requires 3 to 5 days in the hospital and several weeks at home. Open surgery is necessary in about 5 percent of gallbladder operations.

The most common complication in gallbladder surgery is injury to the bile ducts. An injured common bile duct can leak bile and cause a painful and potentially dangerous infection. The majority of bile leaks can be treated successfully by ERCP. Major injury, however, is more serious and requires additional surgery.

Do people need their gallbladder?

Fortunately, the gallbladder is an organ people can live without. Your liver produces enough bile to digest a normal diet. Once the gallbladder is removed, bile flows out of the liver through the hepatic ducts into the common bile duct and directly into the small intestine, instead of being stored in the gallbladder. Because now the bile flows into the small intestine more often, mild diarrhea can occur after cholecystectomy. This diarrhea can be easily treated with bile salt binders (i.e. cholestyramine).


Points to Remember

  • Gallstones form when bile hardens.
  • Gallstones typically form in the gallbladder, but can also form in the bile ducts.
  • Gallstones are more common among older adults; women; American Indians; Mexican Americans; people with diabetes; those with a family history of gallstones; people who are overweight, obese, or undergo rapid weight loss; and those taking cholesterol-lowering drugs.
  • Gallbladder attacks often occur after eating a meal, especially one high in fat.
  • Symptoms can mimic those of other problems, including a heart attack or stomach ulcer, so an accurate diagnosis is important.
  • Gallstones can cause serious problems if they become trapped in the bile ducts.
  • Laparoscopic surgery to remove the gallbladder is the most common treatment.


Reprinted with modifications from the National Digestive Diseases Information Clearinghouse.