Gallstones

Summary

• Gallstones form when liquid stored in the gallbladder hardens into pieces of stone-like material.
• The two types of gallstones are cholesterol stones and pigment stones.
• Many people have no symptoms and are unaware they have gallstones.
  
• Gallstones are not totally preventable and may occur in susceptible persons.

Description

The gallbladder is a small pear-shaped pouch about three to six inches long. It is tucked just under the liver and is connected to the intestine and liver by small tubes called bile ducts. Bile ducts carry bile, a greenish-brown fluid that is made in the liver. Bile acts like a detergent, breaking up fat from the food we eat into small droplets. It also enables the body to absorb vitamins A, D, E and K. Bile is concentrated and stored in the gallbladder, ready for use and is only released when we eat. Gallstones form when liquid stored in the gallbladder hardens into pieces of stone-like material.

Cause

The two types of gallstones are cholesterol stones and pigment stones.

• Cholesterol stones - Bile contains water, cholesterol, fats, bile salts, and bilirubin. Bile salts break up fat, and bilirubin gives bile and stool a brownish colour. If the liquid bile contains too much cholesterol, too much bilirubin, or not enough bile salts, or when the gallbladder does not empty, as it should for some other reason, it can promote cholesterol stone forming. Cholesterol stones are usually yellow-green and are made primarily of hardened cholesterol. They account for about 80 percent of gallstones.
• Pigment stones - The cause of pigment stones is uncertain. They tend to develop in people who have cirrhosis, biliary tract infections, and hereditary blood disorders, such as sickle cell anaemia. Pigment stones are small, dark stones made of bilirubin.

Gallstones can be as small as a grain of sand or as large as a golf ball. The gallbladder can develop just one large stone, hundreds of tiny stones, or almost any combination.

The gallbladder and the ducts that carry bile and other digestive enzymes from the liver, gallbladder, and pancreas to the small intestine are called the biliary system.

Gallstones can block the normal flow of bile if they lodge in any of the ducts that carry bile from the liver to the small intestine. That includes the hepatic ducts, which carry bile out of the liver; the cystic duct, which takes bile to and from the gallbladder; and the common bile duct, which takes bile from the cystic and hepatic ducts to the small intestine. Bile trapped in these ducts can cause inflammation in the gallbladder, the ducts, or, rarely, the liver. Other ducts open into the common bile duct, including the pancreatic duct, which carries digestive enzymes out of the pancreas. If a gallstone blocks the opening to that duct, digestive enzymes can become trapped in the pancreas and cause an extremely painful inflammation called pancreatitis.

If any of these ducts remain blocked for a significant period of time, severe - possibly fatal - damage can occur, affecting the gallbladder, liver, or pancreas. Warning signs of a serious problem are fever, jaundice, and persistent abdominal pain.

Symptoms

Many people with have no symptoms and are unaware that they have gallstones until the stones show up in tests performed for other reasons. When symptoms do develop, it is usually because the gallbladder wall becomes inflamed or because the stones have moved out of the gallbladder and block the tube connected to the intestine. A typical gallstone "attack" may occur suddenly and often follows a fatty meal, frequently occurring during the night. The attack starts as a continuous upper abdominal pain that increases rapidly and lasts from 30 minutes to several hours.

The following symptoms may also be experienced:

• Pain in the back between the shoulder blades or pain under the right shoulder
• Nausea or vomiting
• Abdominal bloating
• Recurring intolerance of fatty foods
• Colic
• Indigestion

Prevalence

It is believed that the mere presence of gallstones may cause more gallstones to develop. However, other factors that contribute to gallstones have been identified, especially in the case of cholesterol stones.

Obesity - Obesity is a major risk factor for gallstones, especially in women. A large clinical study showed that being even moderately overweight increases one's risk for developing gallstones. The most likely reason is that obesity tends to reduce the amount of bile salts in bile, resulting in more cholesterol. Obesity also decreases gallbladder emptying.

Oestrogen - Excess oestrogen 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.

Gender - Women between 20 and 60 years of age are twice as likely to develop gallstones as men.

Age - People over 60 are more likely to develop gallstones than younger people.

Cholesterol-lowering drugs - Drugs that lower cholesterol levels in the blood actually increase the amount of cholesterol secreted in bile. This in turn can increase the risk of gallstones.

Diabetes - People with diabetes generally have high levels of fatty acids called triglycerides. These fatty acids 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 the bile, which can cause gallstones.

Fasting - Fasting decreases gallbladder movement, causing the bile to become over-concentrated with cholesterol, which can lead to gallstones.

Course

The stone can block the ducts that carry bile to the intestines. This may result in jaundice, infection or inflammation of the pancreas, liver, or gallbladder. Death may occur from some of these complications. Scarring of the gallbladder or the stone may erode through the gallbladder causing a general bowel infection and blockage.

It is not certain whether gallstones increase one's risk of gallbladder cancer.

Risk Factors

• Women - Pregnant women, women on hormone therapy, and women who use birth control pills.
• People over 60
• Overweight - Men and women
• People who fast or lose a lot of weight quickly

When to see a doctor

People with the following symptoms should see a doctor soon as possible:

• Sweating
• Chills
• Low-grade fever
• Yellowish colour of the skin or whites of the eyes
• Clay-coloured stools.

Gallstones may simulate the symptoms of a heart attack, appendicitis, ulcers, irritable bowel syndrome, hiatus hernia, pancreatitis, and hepatitis. Accurate diagnosis is therefore important.

Diagnosis

Gallstones, especially "silent" stones, are often discovered by chance during tests for other problems. When gallstones are suspected to be the cause of symptoms, the doctor is likely to do an ultrasound exam. Ultrasound uses sound waves to create images of organs. Sound waves are sent toward the gallbladder through a handheld device that a technician glides over the abdomen. The sound waves bounce off the gallbladder, liver, and other organs, and their echoes create electrical impulses that form a picture of the organ on a video monitor. If stones are present, the sound waves will bounce off them, too, showing their location.

Other tests used in diagnosis include:

• Cholecystogram or cholescintigraphy - The patient is injected with a special iodine dye, and X-rays are taken of the gallbladder over a period of time. (Some people swallow iodine pills the night before the X-ray.) The test shows the movement of the gallbladder and any obstruction of the cystic duct.
• Endoscopic retrograde cholangiopancreatography (ERCP) - The patient swallows 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, and then injects a special dye that temporarily stains the ducts in the biliary system. ERCP is used to locate stones in the ducts.
• Blood tests - Blood tests may be used to look for signs of infection, obstruction, pancreatitis, or jaundice.

Treatment

Surgery

Surgery to remove the gallbladder is the most common way to treat symptomatic gallstones. (Asymptomatic gallstones usually do not need treatment.) The surgery is called cholecystectomy.

The standard surgery is called laparoscopic cholecystectomy. For this operation the 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 the surgeon a close-up view of the organs and tissues. While watching the monitor, the surgeon uses the instruments to carefully separate the gallbladder from the liver, ducts, and other structures. Then the cystic duct is cut and the gallbladder removed through one of the small incisions.

Because the abdominal muscles are not cut during laparoscopic surgery, patients have less pain and fewer complications than they would have had after surgery by means of a large incision across the abdomen. Recovery usually involves only one night in hospital, followed by several days of restricted activity at home.

If the surgeon discovers any obstacles to the laparoscopic procedure, such as infection or scarring from other operations, the operating team may have to switch to open surgery. In some cases the obstacles are known before surgery, and an open surgery is planned from the start. It is called "open" surgery because the surgeon makes a 10-15 cm incision in the abdomen to remove the gallbladder. This is a major surgery and may require a 2- to 7-day stay in the hospital and several more weeks at home to recover. Open surgery is required in about 5 percent of gallbladder operations.

The most common complication in gallbladder surgery is injury to the bile ducts. An injured common bile duct can leak bile and cause a painful and potentially dangerous infection. Mild injuries can sometimes be treated nonsurgically. Major injury, however, is more serious and requires additional surgery.

If gallstones are in the bile ducts, the surgeon may use ERCP in removing them before or during the gallbladder surgery. Once the endoscope is in the small intestine, the surgeon locates the affected bile duct. An instrument on the endoscope is used to cut the duct, and the stone is captured in a tiny basket and removed with the endoscope. This two-step procedure is called ERCP with endoscopic sphincterotomy.

Occasionally, a person who has had a cholecystectomy is diagnosed with a gallstone in the bile ducts weeks, months, or even years after the surgery. The two-step ERCP procedure is usually successful in removing the stone.

Nonsurgical Treatment

Nonsurgical approaches are used only in special situations, e.g. when a patient's condition prevents using an anesthetic, and only in the case of cholesterol stones. Stones recur after nonsurgical treatment in about in 50% of cases.

• Oral dissolution therapy - Drugs made from bile acid, e.g. chenic acids, are used to dissolve the stones. This works best for small cholesterol stones. Months or years of treatment may be necessary before all the stones dissolve. These drugs cause mild diarrhea, and may temporarily raise levels of blood cholesterol and the liver enzyme transaminase.
• Contact dissolution therapy - This experimental procedure involves injecting a drug directly into the gallbladder to dissolve stones. The drug, methyl tert butyl, can dissolve some stones in 1 to 3 days, but it must be used very carefully because it is a flammable anesthetic that can be toxic. The procedure is currently being tested in patients with symptomatic, noncalcified cholesterol stones.
• Extracorporeal shockwave lithotripsy (ESWL) - This treatment uses shock waves to break stones into tiny pieces that can pass through the bile ducts without causing blockages. Attacks of biliary colic (intense pain) are common after treatment, and ESWL's success rate is not very high. Remaining stones can sometimes be dissolved with medication.

Fortunately, the gallbladder is an organ that people can live without. Losing it does not even require a change in diet. Once the gallbladder is removed, bile flows out of the liver through the hepatic ducts into the common bile duct and goes directly into the small intestine, instead of being stored in the gallbladder. However, because the bile is not stored in the gallbladder, it flows into the small intestine more readily, causing diarrhea in some people. Some studies suggest that removing the gallbladder may cause higher blood cholesterol levels, so regular cholesterol tests may be necessary.

Prevention

Due to diverse risk factors, gallstones are not totally preventable and may occur in susceptible persons.

Reviewed by Prof. Don du Toit, Faculty of Health Sciences, University of Stellenbosch