A gallstone is a lump of hard material usually ranging in size from a grain of sand to 3-4 cm. They are formed inside the gallbladder as a result of precipitation of cholesterol and bile salts from the bile.
Types of gallstones and causes
Cholesterol stones are usually yellow-green and are made primarily of hardened cholesterol. They account for about 80% of gallstones. Scientists believe cholesterol stones form when bile contains too much cholesterol, too much bilirubin, not enough bile salts or when the gallbladder does not empty as it should.
Pigment stones are small, dark deposits of bilirubin. The exact cause is not known. They tend to develop in people who have cirrhosis, biliary tract infections, and hereditary blood disorders such as sickle cell anaemia in which too much bilirubin is formed.
Mixed stones are the most common type. They are comprised of both cholesterol and salts.
Other causes are related to excess excretion of cholesterol by liver through bile, and include:
- Gender: Women between 20 and 60 years of age are twice as likely to develop gallstones as men.
- Obesity: Obesity is a major risk factor for gallstones, especially in women.
- Oestrogen: Excess oestrogen during pregnancy, hormone replacement therapy or birth control pills can cause the development of gallstones.
- Cholesterol-lowering drugs
- Diabetes: People with diabetes generally have high levels of fatty acids called triglycerides, which can deposit as gallstones.
- Rapid weight loss: As the body metabolises fat during rapid weight loss, it causes the liver to secrete extra cholesterol into bile, which can cause gallstones.
Many people with gallstones have no symptoms. These patients are said to be asymptomatic, and these stones are called "silent stones”. When symptoms do occur they are similar to those of heart attack, appendicitis, ulcers, irritable bowel syndrome, hiatal hernia, pancreatitis and hepatitis. So accurate diagnosis is important.
Symptoms may vary, often following fatty meals, and may occur during the night.
- Abdominal bloating
- Recurring intolerance of fatty foods
- Steady pain in the 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 or vomiting
- Indigestion and belching
Ultrasound is the most sensitive and specific test for gallstones.
Other diagnostic tests may include
- Computed tomography (CT) scan may show gallstones or complications.
- Endoscopic retrograde cholangiopancreatography (ERCP) involves the insertion of an endoscope - a long, flexible, lighted tube connected to a computer and TV monitor. The doctor guides the endoscope through the stomach and into the small intestine. A special dye is then injected that temporarily stains the ducts in the biliary system. ERCP is used to locate and remove stones in the ducts.
- Blood tests may be used to look for signs of infection, obstruction, pancreatitis or jaundice.
Course of illness
Bile-duct blockage and infection caused by stones in the biliary tract can be life-threatening. With prompt diagnosis and treatment, the outcome is usually very good.
The obstruction caused by a gallstone may lead to biliary colic, inflammation of the gallbladder (Cholecystitis). Other complications may include
- Cirrhosis is the result of chronic liver disease that causes scarring of the liver (fibrosis - nodular regeneration) and liver dysfunction.
- Cholangitis is an infection of the common bile duct, which carries bile (helps in digestion) from the liver to the gallbladder and then to the intestines.
Surgery to remove the gallbladder is the most common way to treat symptomatic gallstones. The most common operation is called laparoscopic cholecystectomy. For this operation, your surgeon makes several tiny incisions in the abdomen and inserts surgical instruments and a miniature video camera into the abdomen. The camera sends a magnified image from inside the body to a video monitor, giving your surgeon a close up view of the organs and tissues. While watching the monitor, your surgeon uses the instruments to carefully separate the gallbladder from the liver, ducts and other structures and remove it through one of the incisions.
If gallstones are in the bile ducts, your physician (usually a gastroenterologist) may use endoscopic retrograde cholangiopancreatography (ERCP) to locate and remove them before or during the gallbladder surgery.