Gallstones
Gallstones are collections of solid crystals (predominantly cholesterol) in the gallbladder or in the bile ducts (biliary tract). When stones are in the gallbladder, the condition is called cholelithiasis; when stones are in the bile ducts, the condition is called choledocholithiasis.
Gallstones are more common among women and among certain groups of people, such as Native Americans. The risk factors for gallstone formation include increased age, obesity, a typical Western diet, and a family history of gallstones. In the United States, about 20% of people older than age 65 have gallstones. Generally, gallstones do not cause symptoms; about 80% of affected people never experience any problems. Each year, more than half a million people in the United States have their gallbladder surgically removed.
 See the figure What Are Gallstones?
In the Western world, the major component of most gallstones is cholesterol, which is insoluble in water yet can dissolve in bile. Bile contains large amounts of cholesterol that usually remains dissolved in the bile. When bile becomes oversaturated with cholesterol, however, the cholesterol becomes insoluble and crystallizes. The microscopic crystals accumulate. Some gallstones are made up of calcium salts and bilirubin, the main pigment in bile (these are called pigmented stones).
Most gallstones form in the gallbladder, which retains the small crystals and allows them to grow. Stones in the bile ducts have usually traveled there from the gallbladder. Stones that form in a bile duct are usually associated with infection or inflammation and consist of pigment material. Any stone in the bile duct system, however, can cause obstruction with inflammation and bacterial infection. A stricture (narrowing) can result, leading to further obstruction of bile flow even after the stone passes.
Symptoms
Most gallstones do not cause any symptoms for many years, if ever, particularly if they remain in the gallbladder.
Typically, gallstones pass from the gallbladder into the bile ducts. If tiny, they may pass through these ducts and into the small intestine without incident, or they may remain in the ducts without obstructing the flow of bile or causing symptoms. Stones that obstruct a bile duct, however, may cause pain as well as nausea and vomiting. Obstruction can allow bacteria to flourish and quickly establish infection in the ducts and occasionally to cause abscesses (pus-filled pockets of infection) in the liver. If an infection develops, it may be accompanied by fever, chills, and jaundice (a yellowish discoloration of the skin and the whites of the eyes). Occasionally, a life-threatening infection called bacterial cholangitis develops. In bacterial cholangitis, the bacteria may spread to the bloodstream and cause infections elsewhere in the body, increasing the risk of death.
Stones that obstruct the outlet of the gallbladder or the cystic duct (the duct that joins the gallbladder with the common bile duct) result in steady pain (biliary colic) in the upper abdomen, usually on the right side under the ribs. This pain comes on gradually, can last from 30 minutes to 12 hours, and resolves. Continued obstruction causes the gallbladder to become inflamed (a condition called acute cholecystitis (see Section 10, Chapter 140)). The pain persists and may extend to the right shoulder blade. The person may have a fever as well.
Stones also can obstruct the pancreatic duct (which joins the pancreas with the common bile duct), causing inflammation of the pancreas (pancreatitis) as well as pain.
Rarely, large gallstones gradually erode the gallbladder wall and enter the small intestine. A gallstone in the small intestine can cause an intestinal obstruction, called a gallstone ileus. This condition occurs more commonly in older people.
Diagnosis
With simple biliary colic, blood test results usually are normal. In acute cholecystitis, the white blood cell count is elevated. With stones obstructing the bile ducts, liver function tests are abnormal, exhibiting a pattern of impaired bile secretion (cholestasis), often with a rise in the amount of the pigment bilirubin. Ultrasound scanning is essential. This method is 95% accurate in detecting gallstones in the gallbladder. Although less accurate in detecting stones in the bile ducts, ultrasound may show that the obstruction has caused the ducts to dilate. Other diagnostic techniques may be necessary, such as endoscopic retrograde cholangiopancreatography (ERCP) (see Section 10, Chapter 134 and Section 10, Chapter 140), computed tomography (CT), or magnetic resonance imaging (MRI) of the biliary and pancreatic system.
Treatment
Most people with gallstones that do not cause any symptoms ("silent" gallstones) do not require treatment. People with intermittent episodes of pain can try avoiding or reducing their intake of fatty foods, but dietary restriction rarely prevents pain or changes the progression of symptoms.
Gallstones in the Gallbladder: If gallstones in the gallbladder cause disruptive recurring attacks of pain, a doctor may recommend surgical removal of the gallbladder (cholecystectomy). Removal of the gallbladder causes no change in digestion. No special dietary restrictions are required after surgery. During cholecystectomy, the doctor may investigate the possibility of stones in the bile ducts.
About 90% of cholecystectomies are performed laparoscopically. In this method, the gallbladder is removed through tubes inserted through small incisions in the abdominal wall. Laparoscopic cholecystectomy has lessened the discomfort after surgery, shortened the length of hospital stays, and reduced sick leave time.
An alternative method of treating gallstone disease without removing the gallbladder involves dissolving gallstones with drugs. Ingestion of bile acids (ursodeoxycholic acid), for example, can dissolve some gallstones. Daily therapy can dissolve tiny stones in 6 months; larger stones may take up to 1 to 2 years. The success rate varies from about 80% for very small stones to less than 40% for large stones, which are the most common. However, even if the stones are successfully dissolved, half of the people so treated develop gallstones again within 5 years.
Gallstones in the Bile Ducts: Stones in the bile ducts can cause serious problems; therefore, they should be removed surgically or by endoscopic retrograde cholangiopancreatography (ERCP). With ERCP, an endoscope (a flexible viewing tube with surgical attachments) is passed through the mouth, down the esophagus, through the stomach, and into the small intestine (see Section 10, Chapter 134). A thin catheter is passed through the endoscope, into the sphincter of Oddi, and up into the common bile duct. Radiopaque dye (a dye that is visible on x-rays) is then injected through the catheter into the bile ducts, and x-rays are taken to detect any abnormalities.
Most stones can be removed from the bile duct during the ERCP procedure. An instrument passed through the endoscope is used to cut the lower bile duct where it joins the duodenum (endoscopic sphincterotomy). Sometimes the stones spill out spontaneously into the duodenum once the cut is made. If not, a basket is passed up into the bile ducts, where it encircles and traps the stone. The basket is then pulled out through the endoscope. When the cut is made, the sphincter of Oddi (between the bile ducts and the duodenum) is opened wide enough to let any future stones that might obstruct the bile duct pass spontaneously into the small intestine and eventually exit in the stool.
ERCP in combination with endoscopic sphincterotomy is successful in 90% of people. Gallstones located only in the gallbladder cannot be removed by this technique. Fewer than 1% of people who undergo this procedure die, and 3 to 7% experience complications, making this procedure a safer option than open abdominal surgery and exploration of the common duct. Immediate complications include bleeding, inflammation of the pancreas (pancreatitis), and perforation or infection of the bile ducts. In 2 to 6% of the people who undergo this procedure, the inflamed ducts narrow (stricture), and stones may develop here in the future.
Most people who have undergone ERCP and endoscopic sphincterotomy later have their gallbladder removed. Otherwise, they are at risk of developing acute gallbladder problems in later years or passing stones into the duct system, causing recurrent obstruction.
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