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Gallstones form when liquid stored in the gallbladder hardens
into pieces of stone-like material. The liquid, called bile, is used
to help the body digest fats. Bile is made in the liver, then stored
in the gallbladder until the body needs to digest fat. At that time,
the gallbladder contracts and pushes the bile into a tube--called
the common bile duct--that carries it to the small intestine, where
it helps with digestion.
Bile contains water, cholesterol, fats, bile salts, proteins, and
bilirubin. Bile salts break up fat, and bilirubin gives bile and
stool a yellowish color. If the liquid bile contains too much
cholesterol, bile salts, or bilirubin, under certain conditions it
can harden into stones.
The two types of gallstones are cholesterol stones and pigment
stones. Cholesterol stones are usually yellow-green and are made
primarily of hardened cholesterol. They account for about 80 percent
of gallstones. 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
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 gallstone pancreatitis.
If any of these ducts remain blocked for a significant period of
time, severe--possibly fatal--damage or infections can occur,
affecting the gallbladder, liver, or pancreas. Warning signs of a
serious problem are fever, jaundice, and persistent pain.
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Scientists believe cholesterol stones form when 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
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 anemia in which too much
bilirubin is formed.
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 for cholesterol
- 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.
- Estrogen. 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.
- Ethnicity. Native Americans have a genetic
predisposition to secrete high levels of cholesterol in bile. In
fact, they have the highest rate 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
also have high rates of gallstones.
- Gender. Women between 20 and 60 years of age are twice
as likely to develop gallstones as men.
- Age. People over age 60 are more likely to develop
gallstones than younger people.
- Cholesterol-lowering drugs. Drugs that lower
cholesterol levels in blood actually increase the amount of
cholesterol secreted in bile. This in turn can increase the risk
- 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 bile, which can cause gallstones.
- Fasting. Fasting decreases gallbladder movement,
causing the bile to become overconcentrated with cholesterol,
which can lead to gallstones.
- people over age 60
- Native Americans
- Mexican Americans
- overweight men and women
- people who fast or lose a lot of weight quickly
- pregnant women, women on hormone therapy, and women who
use birth control pills
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Symptoms of gallstones are often called a gallstone "attack"
because they occur suddenly. A typical attack can cause
- 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
Gallstone attacks often follow fatty meals, and they may occur
during the night. Other gallstone symptoms include
- abdominal bloating
- recurring intolerance of fatty foods
People who also have the above and any of following symptoms
should see a doctor right away:
- low-grade fever
- yellowish color of the skin or whites of the eyes
- clay-colored stools
Many people with gallstones have no symptoms. These patients are
said to be asymptomatic, and these stones are called "silent
stones." They do not interfere in gallbladder, liver, or pancreas
function and do not need treatment.
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Many gallstones, especially silent stones, are discovered by
accident during tests for other problems. But 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 such as a
pregnant uterus, and their echoes make electrical impulses that
create a picture of the organ on a video monitor. If stones are
present, the sound waves will bounce off them, too, showing their
location. Ultrasound is the most sensitive and specific test for
Other tests used in diagnosis include
- Computed tomography (CT) scan may show the gallstones
- MR cholangiogram may diagnose blocked bile
- Cholescintigraphy (HIDA scan) is used to diagnose
abnormal contraction of the gallbladder or obstruction. The
patient is injected with a radioactive material that is taken up
in the gallbladder, which is then stimulated to contract.
- 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. The
doctor then injects a special dye that temporarily stains the
ducts in the biliary system. ERCP is used to locate and remove
stones in the ducts.
- Blood tests. Blood tests may be used to look for signs
of infection, obstruction, pancreatitis, or
Gallstone symptoms are similar to those of heart attack,
appendicitis, ulcers, irritable bowel syndrome, hiatal hernia,
pancreatitis, and hepatitis. So accurate diagnosis is
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Surgery to remove the gallbladder is the most common way to treat
symptomatic gallstones. (Asymptomatic gallstones usually do not need
treatment.) Each year more than 500,000 Americans have gallbladder
surgery. The surgery is called cholecystectomy.
The most common operation 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 closeup
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
Because the abdominal muscles are not cut during laparoscopic
surgery, patients have less pain and fewer complications than they
would have had after surgery using a large incision across the
abdomen. Recovery usually involves only one night in the 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.
It is called "open" surgery because the surgeon has to make a 5- to
8-inch incision in the abdomen to remove the gallbladder. This is a
major surgery and may require about 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 physician (usually a
gastroenterologist) may use endoscopic retrograde
cholangiopancreatography (ERCP) to locate and remove them before or
during the gallbladder surgery. In 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. The doctor then injects a special dye
that temporarily stains the ducts in the biliary system. Then the
affected bile duct is located and an instrument on the endoscope is
used to cut the duct. The stone is captured in a tiny basket and
removed with the endoscope.
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 approaches are used only in special situations--such
as when a patient has a serious medical condition preventing
surgery--and only for cholesterol stones. Stones usually recur after
- Oral dissolution therapy. Drugs made from bile acid are
used to dissolve the stones. The drugs, ursodiol (Actigall) and
chenodiol (Chenix), work best for small cholesterol stones. Months
or years of treatment may be necessary before all the stones
dissolve. Both drugs cause mild diarrhea, and chenodiol may
temporarily raise levels of blood cholesterol and the liver enzyme
- Contact dissolution therapy. This experimental
procedure involves injecting a drug directly into the gallbladder
to dissolve stones. The drug--methyl tertbutyl ether--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 being tested in patients with symptomatic,
noncalcified cholesterol stones.
- Extracorporeal shockwave lithotripsy (ESWL). This
treatment uses shock waves to break up 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 known. This approach is
usually combined with therapeutic ERCP.
Fortunately, the gallbladder is an organ that people can
live without. Losing it won't 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 isn't stored in the
gallbladder, it flows into the small intestine more
frequently, causing diarrhea in about 1 percent of
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- Gallstones form when substances in the bile harden.
- Gallstones are more common among women, Native Americans,
Mexican Americans, and people who are overweight.
- Gallstone attacks often occur after eating a meal.
- Symptoms can mimic those of other problems, including heart
attack, so accurate diagnosis is important.
- Gallstones can cause serious problems if they become trapped
in the bile ducts.
- Laparoscopic surgery to remove the gallbladder is the most
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