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Like many people, you may have gallstones and not know it. In fact, gallstones — solid deposits of cholesterol or calcium salts that form in your gallbladder or nearby bile ducts — often cause no symptoms and require no treatment. But some people with gallstones will have a gallbladder attack that can cause symptoms such as nausea and an intense, steady ache in their upper middle or upper right abdomen. In some cases, the pain can be severe and intermittent.

Gallstones affect as many as one in 12 Americans. You're at greater risk of developing gallstones if you're older, female or overweight. Rapid weight loss or eating a very low calorie diet also can put you at risk of gallstones.

Complications from gallstones can be serious, and even fatal, if left untreated. Fortunately, treatment is usually straightforward, and newer techniques often allow faster recovery time.

You may not know you have gallstones until they're discovered during tests done for other reasons. But sometimes gallstones may cause certain signs and symptoms. These include:

• Chronic indigestion. Signs and symptoms of indigestion may include nausea, gas, bloating and sometimes abdominal pain. These signs and symptoms may occur or be made worse after you eat high-fat foods. But even if you have gallstones, they often aren't the cause of your digestive problems. A number of other conditions — including gastroesophageal reflux disease (GERD) and peptic ulcers of the stomach or duodenum — also can cause chronic indigestion. For that reason, it's important to discuss your symptoms carefully with your doctor.
• Sudden, steady and moderate to intense pain in your upper middle or upper right abdomen. This may signal a gallbladder attack. The pain may occur one to two hours after eating but may also occur at other times — even at night. It can last from 15 to 30 minutes to several hours. Gallbladder pain starts in your upper middle or upper right abdomen and, on occasion, may shift to your back or right shoulder blade. After the pain subsides, you might have a mild aching or soreness in your upper abdomen that can last for up to a day or so. Gallbladder attacks tend to occur infrequently — weeks, months or even years apart.
• Nausea and vomiting. These signs and symptoms may accompany a gallbladder attack.

Gallstones sometimes get trapped in the neck of the gallbladder and can cause persistent pain that lasts several hours and is accompanied by fever. If you experience this type of persistent pain or you have a fever with the pain, seek medical attention right away.

Sometimes small gallstones escape the gallbladder and enter the duct leading from your liver and gallbladder to your small intestine (common bile duct). They may also occasionally enter the duct leading to your pancreas. In some cases, a stone may block this duct — a condition called pancreatitis, which can be fatal if you don't receive treatment. You'll likely have pain and sometimes fever due to inflammation at or near the site of the blockage. Other signs and symptoms of bile duct obstruction include:

• Yellowing of your skin and the whites of your eyes (jaundice)
• Clay-colored stools
• Dark urine
• Fever
• Chills

If you experience any of these signs and symptoms, seek medical treatment right away. Keep in mind that sometimes you may have jaundice and changes in the color of your urine or stools without also having much pain or indigestion. It may take a few days before you notice the discoloration.

Your liver produces bile — a greenish-brown fluid composed of bile salts, fatty compounds, cholesterol and other chemicals. This fluid is concentrated and stored in your gallbladder until it's needed to help digest fats in your small intestine.

When you eat, your gallbladder contracts and releases bile through the cystic duct and into the common bile duct. The common bile duct then carries bile to the upper part of your small intestine (duodenum), where it begins to help break down the fat in your food. But if bile within your gallbladder becomes chemically unbalanced, it can form into hardened particles that eventually grow into stones. This may take several years.

Gallstones can be as small as a grain of sand or as large as a golf ball and may be smooth and round or irregular with a number of edges. You can have just one stone or hundreds of them.

Categories of gallstones
No matter what their size, shape or number, gallstones fall into one of three categories:

• Cholesterol gallstones. These gallstones, often yellow in color, are composed mainly of undissolved cholesterol, although they can also have other components, such as calcium and bilirubin, the residue from the breakdown of red blood cells. About 80 percent of gallstones are cholesterol stones.
• Pigment gallstones. These small, dark brown or black stones form when your bile contains too much bilirubin. It's not always clear what causes them. They tend to form in people with conditions — such as cirrhosis, biliary tract infection and sickle cell anemia — that result in excess bilirubin forming.
• Primary bile duct stones. Unlike stones that form in your gallbladder but escape into your bile ducts, these stones form in the ducts themselves. Primary bile duct stones are rare.

Contributors to gallstones
Many factors, some of which aren't well understood, contribute to the formation of gallstones. They include:

• Too much cholesterol. Normally, your bile contains enough bile salts and lecithin — a fatty compound — to dissolve the cholesterol excreted by your liver. But if your bile contains more cholesterol than can be dissolved, the cholesterol may form into crystals and eventually into stones. Cholesterol in your bile has no relation to the levels of cholesterol in your blood, and cholesterol-lowering drugs don't help prevent gallstones.
• Incomplete or infrequent gallbladder emptying. If your gallbladder doesn't empty completely or often enough, bile may become too concentrated and contribute to the formation of gallstones. This may occur during pregnancy. Eating too little fat or going long periods without eating, such as skipping breakfast, also can decrease gallbladder contractions. Fewer contractions can keep the gallbladder from emptying completely or frequently.

Gallstones tend to run in families. Other factors that may increase your risk include:

• Sex. Women between the ages of 20 and 60 are more than twice as likely as men are to have gallstones. That's because the female hormone estrogen causes more cholesterol to be excreted in bile. Pregnancy, which causes estrogen levels to rise, also increases the risk. In addition, birth control pills and hormone therapy (HT) both increase bile cholesterol levels and decrease gallbladder emptying. If you take these medications and are concerned about gallstones, talk to your doctor. HT has other potential side effects as well. Taking HT as a combination therapy — estrogen plus progestin — can result in serious health risks. Work with your doctor to evaluate the options and decide what's best for you.
• Body weight. As your body mass index (BMI) — a method of estimating your percentage of body fat using your height and weight — increases, so does your risk of developing gallstones. Being even moderately overweight increases cholesterol in your bile. It also decreases bile salts and reduces the frequency with which your gallbladder contracts and empties.
• Diet. Low-calorie, rapid-weight-loss diets tend to disrupt your bile chemistry and may cause your gallbladder to contract less often. This makes it more likely you'll develop gallstones. In fact, losing more than 3 pounds a week may increase your risk of developing gallstones when compared with losing weight more gradually. People who undergo gastrointestinal surgery to lose weight rapidly, also called bariatric surgery, are at increased risk of gallstones. As many as one in three people who have bariatric surgery may develop symptomatic gallstones a few months after surgery.
• Age. Your chance of developing gallstones increases with age. People older than 60 years of age are more likely to have gallstones than are those who are younger.
• Ethnicity. American Indians have the highest incidence of gallstones in the United States. Mexican-Americans also are at increased risk.

Call your doctor if you develop a sudden, intense pain in your abdomen, especially if you also have nausea, vomiting or fever. If you develop one or more symptoms of bile duct obstruction — abdominal pain, yellowing of your skin and the whites of your eyes, dark urine, and a high fever with chills — seek emergency care.

Many gallstones, especially those that don't cause signs or symptoms, are discovered during tests — including ultrasounds or computerized tomography scans — done for other reasons. If you have signs or symptoms of gallstones, your doctor is likely to suspect them based on your medical history and a physical exam. During the exam, he or she will check for jaundice of your skin or the whites of your eyes and will feel (palpate) your abdomen to see if it's tender. If your doctor suspects gallstones, you may have a blood test to check for signs of infection (shown by an elevated white blood cell count), abnormal levels of liver or pancreatic enzymes, or excess bilirubin.

You may also undergo these diagnostic tests:

• Ultrasonography. An ultrasound test uses sound waves rather than X-rays to display an image of the organs in your abdomen, including your gallbladder. It's often the best way to detect gallstones in your gallbladder and sometimes in the common bile duct.
• Computerized tomography (CT) scan. A CT scan is a diagnostic imaging procedure that uses a series of computer-generated X-rays to provide a comprehensive view of your internal organs.
• Radionuclide scan (cholescintigraphy, HIDA scan). In this test, you'll receive a small amount of a radioactive tracer material through your veins (intravenously), followed by a scan of the gallbladder to see if the tracer material gains access to the gallbladder. If it doesn't, a stone is likely blocking the opening of the gallbladder or cystic duct.
• Endoscopic retrograde cholangiopancreatography (ERCP). Your doctor may perform this procedure to help locate and remove stones in the ducts. During ERCP, a flexible, lighted viewing instrument (endoscope) is gently passed down your throat, through your stomach and into the upper part of your small intestine (duodenum). Air is used to inflate your intestinal tract so that your doctor can more easily see the openings of the bile and pancreatic ducts. Then, a dye is injected into these ducts through a tiny hollow tube (cannula) that's passed through the endoscope. Finally, X-rays are taken of the ducts. If a stone is blocking one of the ducts, a specialized kind of cutting instrument may be inserted through the endoscope to try to remove the stone. A less invasive alternative, called magnetic resonance cholangiopancreatography, is used in some medical centers to diagnose blocked bile ducts. However, this technique doesn't allow for the removal of the stone.
• Endoscopic ultrasound (EUS). In some cases, your doctor may use this technique to help diagnose stones in the common bile duct. In this procedure, an ultrasound transducer is placed on the tip of an endoscope, which is then gently passed down your throat and through your stomach. Because the ultrasound instrument is closer to the bile ducts, it provides clearer and more accurate images than does traditional ultrasound. EUS is a less invasive and complex procedure than is ERCP, but if any stones need to be removed, your doctor will still need to perform an ERCP.

Complications of gallstones may include:

• Blockage of the common bile duct. In some cases, gallstones can block the ducts that lead from your gallbladder, liver or pancreas to your small intestine. The signs and symptoms of common bile duct obstruction include yellowing of the whites of the eyes and skin (jaundice), dark urine, and pain in the upper abdomen. If you also have fever and chills, you may have an underlying complication such as an inflamed gallbladder (cholecystitis) or an infection in your bile duct (cholangitis).
• Inflammation of the pancreas. An obstruction in the common bile duct near the junction with the pancreatic duct can also cause a blockage in the pancreatic duct or inflammation of the pancreas (acute pancreatitis). In many people the common duct and the pancreatic duct empty into the duodenum at a common opening. Pancreatitis is likely to cause an intense, constant pain in your upper abdomen that may radiate to your back or chest. The pain is usually worse when you lie flat and better when you sit up or bend forward. You may not be able to pass gas, and your abdomen may be tender and distended. Sometimes, you may also have nausea, vomiting and fever. In mild cases, symptoms usually subside within a few days to a week, but severe acute pancreatitis can be life-threatening.
• Gallbladder cancer. People with gallstones are also more likely to develop gallbladder cancer. Researchers speculate that gallstones may cause your gallbladder to release bile more slowly, which increases the amount of time cells are exposed to toxins. However, gallbladder cancer is rare and the vast majority of people with gallstones never develop gallbladder cancer.

Because the majority of gallstones produce no symptoms, they require no treatment. Doctors often discover these "silent stones" during routine medical checkups or exams for other illnesses and usually recommend taking a wait-and-see approach to treatment. If your gallstones cause symptoms, however, several possible treatments are available.

Surgery
Removing the gallbladder is the preferred treatment for the majority of people who have gallstones that cause symptoms. In fact, gallbladder surgery (cholecystectomy) is one of the most common surgeries performed in the United States. The surgery can be performed in two ways:

• Laparoscopic surgery. Most often gallbladder surgery is performed using a laparoscope, a pencil-thin tube with its own lighting system and miniature video camera. A surgeon inserts the laparoscope into your abdomen through a hollow instrument (cannula). Only small incisions are required. The video camera then produces a magnified view on a television monitor of the inside of your abdomen. This allows the surgeon to see the surgery in detail. To remove your gallbladder, he or she uses tiny instruments inserted through several other small abdominal incisions. Because laparoscopic cholecystectomy uses smaller incisions, you'll likely have less postoperative pain, less scarring and an earlier return to your normal activity — often within just a few days. Laparoscopic removal of the gallbladder is effective in the majority of cases.
• Open surgery. Occasionally an option is open surgery, in which the gallbladder is removed through a large abdominal incision. Your doctor may regard this surgery as the best option in severe cases. It may also be used when the gallbladder walls are thick and hard, the gallbladder is obviously infected, or there is scar tissue from earlier abdominal operations. Recovery from open surgery typically entails up to a week's stay in the hospital, followed by several weeks at home.

After surgery your liver continues to produce enough bile to digest a normal diet. But you may notice you're having more bowel movements than usual and that their consistency is less solid. For some people these changes can be major. In most cases the symptoms usually lessen over time. When diarrhea remains a problem, general self-care measures — such as avoiding dairy products, fats and spicy foods as well as adding more fiber to your diet — may help. If diarrhea persists, see your doctor, because medications can sometimes help.

If you have stones in the bile duct as well as your gallbladder, your doctor may recommend surgical removal of both the duct stones and your gallbladder. But in some cases, your doctor may suggest removing the stones in the bile duct using an endoscope (ERCP). Your gallbladder also may be removed at a later date. Often, a cutting instrument is inserted through the endoscope, and the entrance of the bile duct is enlarged so the stone can pass through it. The same procedure may be used to remove a stone from a blocked pancreatic duct.

Nonsurgical options
Stones usually recur when nonsurgical treatments are used. However, when surgery isn't the best option, your doctor may recommend one of the following options:

• Bile salt tablets. Your doctor may have you take the medication ursodiol (Actigall), which dissolves cholesterol stones over a period of time. The treatment works best on small cholesterol stones. To prevent a recurrence, most people need to take the medication indefinitely.
• Sound wave therapy (extracorporeal shock wave lithotripsy). This treatment uses high-frequency sound waves to break up gallstones. You then take ursodiol tablets to dissolve the fragments. Sound wave therapy is appropriate for only a small percentage of people with gallstones. If you have more than one stone, your stone is large, or you have acute cholecystitis or cholangitis, you're probably not a good candidate for this treatment. And, as with other nonsurgical therapies, your gallstones are likely to return unless you take ursodiol indefinitely.

Although you can't entirely prevent gallstones from forming, you may be able to lower your risk by following these suggestions:

• Maintain a healthy body weight.
• Avoid crash diets or a very low intake of calories — less than 800 calories a day.
• Exercise regularly.
• Choose a low-fat, high-fiber diet that emphasizes fresh fruits, vegetables and whole grains. Reduce the amount of animal fat, butter, margarine, mayonnaise and fried foods you eat.