Gallstones are hard, stone-like masses that develop in the gallbladder or bile ducts. They are composed of substances such as cholesterol or bilirubin, which occur in bile, a fluid produced in the liver.  

An estimated 16 million to 22 millions Americans, or one in 12 people, have gallstones, according to the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK).

Many people with gallstones do not experience symptoms but, when they do, the most common is pain in the upper abdomen. Other symptoms may include nausea, vomiting and jaundice. Gallstones can cause serious complications, such as inflammation of the gallbladder (cholecystitis), infection of the bile duct (cholangitis) and inflammation of the pancreas (pancreatitis).

The causes of gallstones are not well understood. Some contributing factors are excess cholesterol in the bile and inadequate emptying of the gallbladder. People Women, older people, obese people and those with a family history of gallstones have an increased risk of developing gallstones.

Gallstones are often identified during imaging tests performed to investigate another medical problem. Diagnosis is aided by a physical examination that includes a medical history.  Imaging tests such as ultrasound, computed axial tomography (CAT) scans and magnetic resonance imaging are the most useful methods to identify gallstones.

Gallstones may be treated in a variety of ways. Those who do not experience symptoms usually receive no treatment. Those experiencing symptoms typically have surgery to remove the gallbladder (cholecystectomy). The formation of gallstones may be prevented by eating a well-balanced diet, maintaining a healthy body weight and exercising regularly.

Gallstones are solid deposits that form in the gallbladder or bile ducts when substances in bile, such as cholesterol and bilirubin, crystalize.

The gallbladder is a pear-shaped organ located in the upper, right side of the abdomen, just beneath the liver. Small tubes called bile ducts connect the gallbladder to the liver and the small intestine.  The gallbladder stores and releases bile, a greenish-brown fluid produced in the liver and used to help the body digest fats.

A series of ducts move bile from the liver to the upper portion of the small intestine, or duodenum. Bile leaves the liver through the hepatic duct and travels to and from the gallbladder through the cystic duct. The junction of the cystic and hepatic ducts forms the common bile duct, which transports bile to the duodenum. The common bile duct joins the duodenum alongside or with the pancreatic duct, which originates in the pancreas.

Bile contains water, cholesterol, bile salts and other fatty substances called lipids. It also contains waste products, such as bilirubin. When the body needs to digest fat, the gallbladder contracts and pushes bile into the ducts that carry it to the small intestine. There, bile dissolves excess cholesterol and bile salts help to break down fat.

Gallstones may form when the balance of components in bile changes. When there is too much cholesterol, the other components may be unable to dissolve the cholesterol and some of the bile hardens into stones. Diminished protein levels in the bile can also cause the cholesterol to crystalize. In addition, when the gallbladder does not contract regularly and empty itself of bile, the concentration of cholesterol in bile can increase to form stones.

Patients can develop one gallstone or up to several hundred. They may be tiny or as large as a golf ball. Most gallstones are smaller than 1 inch (2.54 centimeters). In some cases, patients have tiny, sandlike gallstones called biliary sludge.

When gallstones form in the gallbladder, the condition is called cholelithiasis. When they form in the bile ducts, the condition is called choledocholithiasis.

Gallstones can block the flow of bile from the liver to the small intestine if they become lodged in ducts. If any of the ducts remain blocked for a significant period of time, severe and possibly even fatal complications can occur in the gallbladder, liver or pancreas. Complications of gallstones may include:

• Common bile duct blockage. Gallstones can block the ducts that lead from the gallbladder, liver or pancreas to the small intestine. This can result in an inflamed gallbladder (cholecystitis) or infection of the bile duct (cholangitis).
  
  
• Pancreatitis (inflammation of the pancreas). This condition typically causes intense pain in the upper abdomen.
  
  
• Gallbladder cancer. People with gallstones face a higher risk of developing gallbladder cancer.

There are two main types of gallstones, including:

• Cholesterol gallstones. About 80 percent of gallstones in the United States are cholesterol gallstones. They are typically yellowish-green in color and composed mainly of cholesterol, although they can contain other substances, such as calcium and bilirubin.
  
  
• Pigment gallstones. Small, dark brown or black stones that are formed when bile contains too much bilirubin. Pigment gallstones are more common among Asians.

The causes of gallstones are not fully understood, but there are several contributing factors. They include:

• Excess cholesterol. When bile contains too much cholesterol, it cannot be dissolved by bile salts. This causes cholesterol to crystalize and possibly form into gallstones.
  
  
• Inadequate gallbladder emptying. If the gallbladder does not empty frequently enough or completely enough, bile can become too concentrated. This contributes to the formation of gallstones. This may happen during pregnancy. Eating too little or avoiding food for long periods of time can decrease gallbladder contractions.

In addition, there are many factors that increase the risk of developing gallstones. They include:

• Gender. Women between the ages of 20 and 60 are more likely to develop gallstones than men.
  
  
• Body weight. People who are obese (particularly women with waistlines exceeding 35 inches) and those who have lost weight rapidly have a greater risk of developing gallstones. Fasting also increases the risk. Research also indicates that men who lose and then regain weight (“weight cycling”) have an increased risk of developing gallstones.
  
  
• Age. The risk of developing gallstones increases with age. People over age 60 face the highest risk.
  
  
• Ethnicity. Gallstones develop more frequently in people of Native American, Hispanic and western Caucasian heritage. African Americans, natives of South Africa and Japanese populations have the lowest rate.
  
  
• Personal history. People who have previously developed gallstones are more likely to develop them again.
  
  
• Family history. The development of gallstones tends to run in families.
  
  
• Estrogen levels. Increased levels of the female hormone estrogen may increase the risk of gallstones by increasing cholesterol levels in bile and decreasing gallbladder movement. Pregnant women, women using hormonal methods of birth control (e.g., oral contraceptives) and postmenopausal women undergoing hormone replacement therapy all have a greater likelihood of developing gallstones.
  
  
• Diseases of the gallbladder and bile ducts. People with disorders of the gallbladder or bile ducts, such as bile duct cysts, are at increased risk for gallstones.
  
  
• Other diseases. People with diseases that involve the small intestine such as Crohn's disease, and metabolic diseases such as diabetes face a higher risk of gallstones. Liver diseases such as cirrhosis may also increase the risk of gallstones.
  
  

  

  
  
• Conditions associated with rapid destruction of red blood cells, such as sickle cell anemia, increase the risk of developing gallstones by causing excess bilirubin in the bile.
  
  
• Medications. Hormonal medications (especially those containing estrogen) may promote gallstones. A hormonal medication used for acromegaly (a disease characterized by excess production of growth hormone) may cause gallstones. Cholesterol lowering medications also increase the risk of developing gallstones by increasing the amount of cholesterol secreted in bile. There are also concerns that a relatively common prescription weight-loss drug may increase gallstone risk in patients.
  
  
• Parenteral nutrition. People who cannot take food by mouth or through their stomachs may receive nutrients through a tube inserted in their veins. These people may have an increased risk of developing gallstones.

Most people with gallstones do not experience symptoms, particularly if the gallstones remain in the gallbladder. They may never know they have gallstones, or discover them while physicians are investigating another problem.

Some people experience symptoms that occur suddenly, which is known as a gallstone attack. The most common symptom of an attack is biliary colic. This constant pain in the upper abdomen lasts from 30 minutes to several hours. Pain may be felt in the back between the shoulder blades or under the right shoulder. Biliary colic is usually caused by the gallbladder contracting in response to a fatty meal, which causes the gallstones to press against and block the cystic duct opening. Attacks often occur at night and the pain may wake the person from sleep.

Other symptoms of an attack may include:

• Nausea or vomiting
• Abdominal bloating or gas
• Belching
• Indigestion

Gallstones that move into and block one of the ducts require immediate medical attention. These blockages can cause inflammation of the gallbladder (acute cholecystitis) or the pancreas (pancreatitis).  

Patients who experience any of the following symptoms of bile duct obstruction should seek medical attention immediately. They include:

• Upper abdominal pain
• Jaundice (yellowing of the skin and whites of the eyes)
• Darkened urine
• Clay-colored stools
• Fever
• Chills
• Sweating

In cases where patients experience no symptoms, gallstones are sometimes discovered as an incidental finding when imaging tests are conducted for another medical problem. When patients experience symptoms, gallstones may be diagnosed during a physical examination that includes a complete medical history.

A physician may perform several blood tests while diagnosing gallstones, usually to check for infection and the function of the liver and pancreatic enzymes. In most cases, imaging tests are used to diagnose gallstones. These imaging tests include:

• Ultrasound. An imaging technology that uses sound waves to produce images of the shape and outline of various tissues and organs of the body. Ultrasound is the imaging test most commonly used for gallstones. An abdominal ultrasound passes a special probe over the gallbladder and may show gallstones. In some cases, an endoscopic ultrasound (EUS) may be performed using an endoscope (lighted tube) inserted in the mouth to the small intestine because it produces better images than a standard ultrasound. EUS is useful for diagnosing gallstones within the bile ducts.
  
  
• X-rays. An image of a body part, organ or bodily system on film paper or fluorescent screens. It is produced by using low doses of radiation. X-rays are only useful in diagnosing gallstones, which contain enough calcium to be visible on an x-ray.
  
  
• Oral cholecystogram (OCG).  Test in which the patient swallows pills containing contrast dye before x-rays are taken. This test is useful in determining gallbladder function.
  
  
• Cholescintigraphy (HIDA scan). A small amount of a radioactive substance is injected intravenously (through a vein). The substance enters the liver and is secreted into bile. It identifies obstructions in the cystic duct and evaluates the ability of the gallbladder to contract.
  
  
• Endoscopic retrograde cholangiopancreatography (ERCP). This procedure is performed when gallstones are suspected in the bile ducts. An endoscope (lighted tube) is inserted through the mouth to the small intestine. A dye is passed through a thin flexible tube (catheter) inside the endoscope before x-rays are taken. ERCP can also be used to remove gallstones from the bile ducts in some cases.
  
  
• Magnetic resonance imaging (MRI). Tests, such as a magnetic resonance cholangiography or a magnetic resonance cholangiopancreatography (MRCP), may be performed instead of an ERCP because they are less invasive. An MRI uses powerful magnets to produce images on a computer screen.
  
  
• Gallbladder bile collection. When imaging tests do not reveal gallstones, but the patient is still experiencing symptoms, a sample of bile may be taken from the duodenum or bile duct during an ERCP or EUS. The bile is examined under a microscope to detect the presence of cholesterol or bile crystals, which may indicate that a small gallstone not detected with other tests is present.
  
  
• Computed axial tomography (CAT) scan. A test that allows for multiple x-rays to be taken from different angles around the patient. It creates images of organs and bones within the body. This may identify the presence of gallstones, but it is not as useful in identifying gallstones as other tests.

Gallstones may be treated in several different ways. People with gallstones who experience no symptoms (silent gallstones) typically do not receive treatment. Though people with silent gallstones may experience symptoms at some point in their lives, it is widely believed that the risks associated with treating gallstones outweigh the potential risk of a future gallbladder attack.

For patients with gallstones located in the gallbladder, treatment involves surgical removal of the gallbladder (cholecystectomy). Although the gallbladder plays an important role in digestion, it is not vital for survival. After it is removed, bile flows from the liver through the hepatic ducts, into the common bile duct and directly into the small intestine, instead of being stored in the gallbladder. Removing the gallbladder may have little impact on digestion and does not usually require a change in diet. However, in a small percentage of patients, it produces mild symptoms, such as loose stools, gas and bloating.

Cholecystectomy is a safe and common procedure that may be performed as open surgery or as a less invasive laparoscopy.  About 80 percent of the gallbladder surgeries performed are now laparoscopic procedures, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

During a laparoscopic cholecystectomy, four or five very small incisions are made in the abdomen and a tiny video camera and surgical instruments are inserted. Video pictures are displayed in the operating room and the gallbladder is removed with the surgical instruments. Because the abdominal muscles are not cut during this procedure, there is less pain following surgery, a shorter hospital stay (sometimes less than a day), faster recovery time and less noticeable scars. Laparoscopic procedures occasionally damage the bile ducts.

Open cholecystectomy may be performed for more complicated surgeries, such as those where infection or a large amount of scar tissue is present. An incision several inches long is made in the abdomen and the gallbladder is removed. The surgery usually requires a three-to-five-day hospital stay followed by several weeks of recuperation at home. The most common complication of cholecystectomy is injury to the bile ducts, although it is rare. Injury can cause bile to leak and result in infection. Minor injuries may be treated with non-surgical methods, but more severe injuries typically require surgical reparation.

Patients who have gallstones in the bile ducts may be treated with surgery to remove them or with endoscopic retrograde cholangiopancreatography (ERCP). This procedure involves inserting an endoscope (lighted tube) through the mouth to the small intestine. A dye is passed through a thin, flexible tube (catheter) inside the endoscope and x-rays are taken.

Gallstones can be removed during an ERCP. An instrument is passed through the endoscope and used to cut the lower bile duct where it joins the duodenum (the first part of the small intestine). One of several instruments may be used to remove the gallstones through the endoscope.

When surgery is not the best option, a patient may be treated with a non-surgical technique. They include:

• Oral dissolution therapy. Medications that contain a natural bile acid are used to dissolve cholesterol gallstones slowly over time. Although they are safe and well-tolerated medications, they can only be used in patients with small gallstones. Most patients need to take the medication for months or years for treatment to be effective.
  
  
• Extracorporeal shock wave lithotripsy (ESWL) This treatment involves the use of high frequency sound waves to break up gallstones. Oral dissolution medication is then taken to dissolve gallstone fragments. This treatment technique is not typically used for patients with more than one stone or a large stone. It is associated with a low success rate and a large degree of pain. ESWL is more commonly used and more effective in treating kidney stones. There is concern about gallstone fragments blocking the bile ducts and ERCP may be performed in association with ESWL.
  
  
• Contact dissolution therapy. This experimental treatment technique involves injecting a medication directly into the gallbladder to dissolve gallstones. It is still in the investigational stages in the United States.

The biggest disadvantage of treating gallstones with a non-surgical technique is that gallstones tend to recur because the gallbladder was not removed. Recurring gallstones may require future treatment.

Although the formation of gallstones cannot be completely prevented, there are several ways to minimize the risk of development. They include:

• Eat a well-balanced diet. Eating a low-fat, high-fiber diet that includes fresh fruits, vegetables and whole grains is recommended. Patients should restrict the amount of animal fat, butter, margarine, mayonnaise and fried foods eaten. Patients should also avoid diets that involve eating very few calories (less than 800 per day).
  
  
• Maintain a healthy body weight.
  
  
• Exercise regularly.
  
  
• Avoid rapid weight loss.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to gallstones:

1. Am I at risk for gallstones? What steps can I take to reduce my risk?
   
   
2. Why do you suspect that I may have gallstones?
   
   
3. Are any tests needed to confirm the diagnosis? How should I prepare for testing?
   
   
4. What caused my gallstones to form?
   
   
5. If a close family member has gallstones, will I get them too?
   
   
6. Should I have my gallbladder removed to treat my gallstones?
   
   
7. What risks are associated with gallbladder surgery?
   
   
8. What types of non-surgical treatments are available to me?
   
   
9. How can I prevent a future gallstone attack?
   
   
10. Can I get gallstones after my gallbladder is removed?