There are two types of gallstones: cholesterol stones and pigment stones. Eighty percent of gallstones are cholesterol stones. The size of gallstones varies from a grain of salt to golf-ball size. A person can develop a single stone or several hundred.
Gallstones form when bile stored in the gallbladder hardens into stone-like material. Too much cholesterol, bile salts, or bilirubin (bile pigment) can cause gallstones. Slow emptying of the gallbladder can also contribute to the formation of gallstones.
When gallstones are present in the gallbladder itself, it is called cholelithiasis. When gallstones are present in the bile ducts, it is called choledocholithiasis. Gallstones that obstruct bile ducts can lead to severe or life-threatening infection of the bile ducts, pancreas, or liver. Bile ducts can also be obstructed by cancer or trauma.
Cholesterol stones are believed to form when bile contains too much cholesterol, too much bilirubin, not enough bile salts, or when the gallbladder does not empty as it should for some other reason.
Pigment stones tend to develop in people who have cirrhosis, biliary tract infections, and hereditary blood disorders such as sickle cell anemia. The causes of these stones are uncertain.
At first, most gallstones do not cause symptoms. However, when gallstones become larger, or when they begin obstructing bile ducts, symptoms or "attacks" begin to occur. Attacks of gallstones usually occur after a fatty meal and at night. The following are the most common symptoms of gallstones. However, each individual may experience symptoms differently. Symptoms may include:
- pain that comes and goes in the abdomen
- jaundice - yellowing of the skin and eyes
- clay-colored stools
- dark urine
- abdominal bloating
- intolerance of fatty foods
- belching or gas
The symptoms of gallstones may resemble other medical conditions or problems. Always consult your physician for a diagnosis.
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors.
Although these risk factors increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors.
But, knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
The following are suggested risk factors for gallstones:
Obesity is a major risk factor for gallstones, especially in women.
Excess estrogen from pregnancy, hormone replacement therapy, or birth control pills appears to increase cholesterol levels in bile and decrease gallbladder movement, both of which can lead to gallstones.
Native Americans have the highest rates of gallstones in this country and seem to have a genetic predisposition to secrete high levels of cholesterol in bile.
Women are twice as likely to develop gallstones than men.
People over 60 are more likely to develop gallstones than younger people.
- cholesterol-lowering drugs
Drugs that lower cholesterol in blood can actually increase the amount of cholesterol secreted in bile, which, in turn, increases the risk of gallstones.
People with diabetes generally have high levels of fatty acids, called triglycerides, which increase the risk of gallstones.
- rapid weight loss
As the body metabolizes fat during rapid weight loss, it causes the liver to secrete extra cholesterol into bile, which can cause gallstones.
Fasting decreases gallbladder movement, which causes the bile to become over-concentrated with cholesterol.
- other conditions
Pigment stones tend to develop in people with cirrhosis, biliary tract infections, and hereditary blood disorders such as sickle cell anemia.
In some cases, asymptomatic gallstones are discovered by accident - during another diagnosis. However, when pain persists, your physician may want to conduct a complete medical history and physical examination, in addition to the following diagnostic procedures for gallstones:
- ultrasound (Also called sonography.) - a diagnostic imaging technique which uses high-frequency sound waves to create an image of the internal organs. Ultrasounds are used to view internal organs of the abdomen such as the liver spleen, and kidneys and to assess blood flow through various vessels.
- cholecystography (Also called oral cholecystography or gallbladder series.) - a series of x-rays are taken of the gallbladder after a special contrast dye is swallowed, making it possible to detect gallstones, cholecystitis, and other abnormalities.
- blood tests (to look for signs of infection, obstruction, jaundice, and/or pancreatitis)
- computed tomography scan (CT or CAT scan) - a diagnostic imaging procedure using a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- endoscopic retrograde cholangiopancreatography (ERCP) - a procedure that allows the physician to diagnose and treat problems in the liver, gallbladder, bile ducts, and pancreas. The procedure combines x-ray and the use of an endoscope - a long, flexible, lighted tube. The scope is guided through the patient's mouth and throat, then through the esophagus, stomach, and duodenum. The physician can examine the inside of these organs and detect any abnormalities. A tube is then passed through the scope, and a dye is injected which will allow the internal organs to appear on an x-ray.
- magnetic resonance cholangiopancreatography (MRCP) - uses magnetic resonance imaging (MRI) to obtain pictures of the bile ducts. The machine uses radio waves and magnets to scan internal organs and tissues.
- sphincterotomy - opening the muscle sphincter, a ring of muscle around a natural opening that acts like a valve, wide enough so stones can pass into the intestine.
Specific treatment for gallstones will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the condition
- your tolerance of specific medicines, procedures, or therapies
- expectations for the course of the condition
- your opinion or preference
If the gallstones cause no symptoms (asymptomatic), treatment is usually not necessary. However, if pain persists, treatment may include:
- gallbladder removal (Also called cholecystectomy.) - once removed, the bile flows directly from the liver to the small intestine. Removal may be achieved through a surgical incision or by laparoscopy. Side effects of this may include diarrhea, because the bile is no longer stored in the gallbladder.
- oral dissolution therapy - drugs made from bile acid are used to dissolve the stones.
- methyl-tert-butyl ether - a solution injected into the gallbladder to dissolve stones.
- extracorporeal shockwave lithotripsy (ESWL) - a procedure that uses shock waves to break stones up into tiny pieces that can pass through the bile ducts without causing blockages.
- contact dissolution therapy - an experimental procedure that involves injecting a drug directly into the gallbladder to dissolve the stones.
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