Gallstones and Bile Duct Stones
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.
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. Being overweight increases one's risk for developing gallstones. Very low calorie, rapid weight-loss diets, and prolonged fasting, seem also to cause gallstone formation. 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 gallstone formation and diet.
Who is at risk for gallstones?
More than 1 million people in the United States each year learn they have gallstones. They will join the estimated 20 million Americans – roughly 10 percent of the population – who already have gallstones.
Those who are most likely to develop gallstones are:
- 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 of lot of weight quickly.
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.
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 an inflammation of the gallbladder (cholecystitis). Blockage of the cystic duct is a common complication cause 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, called cholangitis, can block bile flow from the gallbladder and liver, causing pain, jaundice and fever. Gallstones may also interfere with the flow of digestive fluids into the small intestine, leading to an inflammation of the pancreas, or pancreatitis. Prolonged blockage of any of these ducts can cause severe damage to the gallbladder, liver, or pancreas which can be fatal.
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.
Other tests may be needed sometimes to detect small stones (or make sure they are not present). These include MRCP (magnetic resonance cholangiopancreatography), EUS (endoscopic ultrasound), and ERCP (endoscopic retrograde cholangiopancreatography). ERCP is particularly relevant for diagnosis and management of stones in the bile duct.
Other gallbladder diseases
The gallbladder can sometimes be painful and become inflamed even in the absence of gallstones. Rare conditions include "acalculus cholecystitis," and "biliary dyskinesia." Acalculus cholecystitis, or inflammation of the gallbladder without stones, tends to occur during other severe illnesses; the gallbladder fluids become stagnant and infected.
Biliary dyskinesia, or disordered function of the gallbladder, describes a condition in which the gallbladder cannot empty properly due to inflammation or spasm of its drainage system (the cystic duct). Pain arises when the gallbladder tries to contract (after meals) against this resistance. These two conditions can be diagnosed by a scanning technique using radioactive isotopes, usually referred to as an HIDA scan. This shows whether the gallbladder is blocked, or cannot drain completely. These conditions are treated in the same way as gallbladder stones.
Cancer can develop in the wall of the gallbladder. It appears to be more common in patients with gallstones. Unfortunately, it often does not cause symptoms until the cancer has spread to the liver or adjacent bile duct. Surgical removal is appropriate where technically possible.
Surgery, called cholecystectomy, is the most common method for treating gallstones despite the development of some nonsurgical techniques. Each year more than 500,000 Americans have gallbladder surgery. There are two types of cholecystectomy – the standard "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 currently the standard procedure for gallbladder removal. About 95 percent of cholecystectomies are done that way. 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.
Laparoscopic cholecystectomy does not require the abdominal muscles to be cut, and thus results in less pain, quicker healing, improved cosmetic results, and fewer complications such as infection. Recovery usually requires only a night in the hospital, and several days recuperation at home.
The most feared complication with the laparoscopic 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.
Difficulties 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 "open" cholecystectomy for safe removal of the gallbladder.
Several methods are available, but are used only in special circumstances.
Patients with acute inflammation of the gallbladder (and acalculus cholecystitis) may sometimes be treated first with "percutaneous drainage." This involves passing a needle and tube, called a catheter, through the abdominal wall directly into the gallbladder, to drain the toxic fluids. Cholecystectomy is performed after the acute situation has settled.
Gallstones which are predominantly made of cholesterol can be slowly"dissolved" with special medicines, made from the acids found naturally in bile. This medical treatment works only when the gallbladder is not blocked, and is more effective with small stones. However, treatment usually requires many months or years (and stones may return when the treatment is stopped). Thus, it is used only rarely in certain individuals who cannot tolerate surgery.
Extracorporeal shockwave lithotripsy (ESWL) is an excellent method for treating stones in the kidneys. It can be used also to break up stones in the gallbladder (the fragments from which then pass spontaneously through into the intestine). However, ESWL often requires several treatments, and has other drawbacks, including the possibility of stone recurrence. It is used only in very rare circumstances.
Treatment of bile duct stones
Approximately 10% of patients with stones in the gallbladder also have stones in the bile duct. These can cause acute blockage to the bile duct with "cholangitis" (with infection and jaundice), or acute pancreatitis. When blockage can cause life threatening illness, emergency treatment is best applied with ERCP (endoscopic retrograde cholangiopancreatography). The gastroenterologist passes an endoscope down to the bile duct opening, and then releases the stone into the duodenum with a small cutting incision (sphincterotomy).
There are many options for treating stones in the bile duct which are not causing severe symptoms. They can be removed with the gallbladder at the time of traditional "open cholecystectomy." Whilst some experts can remove bile duct stones during the newer less invasive "laparoscopic" cholecystectomy, this technique of laparoscopic common bile duct exploration is available only in a few specialist centers. Thus, there is an increasing tendency to use a combination approach – laparoscopic cholecystectomy for the gallbladder stones, and ERCP for the stones in the bile duct. ERCP is used beforehand when it is obvious from the clinical presentation and tests that a stone is present. ERCP can be performed after laparoscopic cholecystectomy when the bile duct stone is found during the operation (by doing an "operative cholangiogram" X-ray).
The above information is adapted from the publication "Gallstones" distributed by the National Digestive Diseases Information Clearinghouse (2 Information Way, Bethesda, MD 20892).