What Are Gallstones?
s 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 fat
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 a duct—that carries it to the small intestine
, where it helps with digestion
s, bile salt
s, and bilirubin
. Bile salts break up fat, and bilirubin
ish color. If the liquid bile
contains too much cholesterol
, bile salt
s, or bilirubin
, it can harden into stones
The two types of gallstone
s 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.
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 duct
, 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 duct to the small intestine
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 enzyme
s out of the pancreas
. If a gallstone
blocks the opening to that duct, digestive enzymes can become trapped in the pancreas
and cause an extreme
ly painful inflammation
If any of these ducts remain block
ed for a significant
period of time, severe
can occur, affecting the gallbladder
, or pancreas
. Warning sign
s of a serious problem are fever
, and persistent pain
What Causes Gallstones?
Scientists believe cholesterol
stones form when bile
contains too much cholesterol
, too much bilirubin
, or not enough bile salt
s, or when the gallbladder
does not empty as it should for some other reason.
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
It is believed that the mere presence of gallstone
s may cause more gallstone
s 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 rates 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 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 bile, which can cause gallstones.
- Fasting. Fasting decreases gallbladder movement, causing the bile to become overconcentrated with cholesterol, which can lead to gallstones.
Who Is at Risk for Gallstones?
What are the Symptoms?
s are often called a gallstone "attack
" because they occur suddenly. A typical attack can cause
Gallstone attacks often follow fat
s, and they may occur during the night
. Other gallstone symptoms
People who also have the following symptoms should see a doctor right away:
Many people with gallstone
s have no symptoms
. These patients are said to be asymptomatic
, and these stones are called "silent stones
." They do not interfere in gallbladder
, or pancreas function
and do not need treatment.
How Are Gallstones Diagnosed?
s, especially silent stones
, are discovered by accident
s for other problems. But when gallstone
s are suspected to be the cause of symptoms, the doctor is likely to do an 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
, and other organs
, and their echo
es 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.
Other tests used in diagnosis include
are similar to those of heart attack
, irritable bowel syndrome
, hiatal hernia
, and hepatitis
. So accurate diagnosis
What is the Treatment?
to remove the gallbladder
is the most common way to treat symptomatic gallstone
s. (Asymptomatic gallstones usually do not need treatment.) Each year more than 500,000 Americans have gallbladder surgery
. The surgery is called cholecystectomy
The standard surgery is called laparoscopic cholecystectomy
. For this operation
, the surgeon
makes several tiny incision
s 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
. While watching the monitor, the surgeon uses the instruments to carefully separate the gallbladder
from the liver
, 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
using a large incision
across the abdomen
. Recovery usually involves only one night in the hospital
, followed by several days of restricted activity
If the surgeon
discovers any obstacle
s to the laparoscopic procedure, such as infection
ring from other operation
s, 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
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
injuries can sometimes be treated nonsurgically. Major injury
, however, is more serious and requires additional surgery
s 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 approaches are used only in special situations—such as when a patient's condition prevents using an anesthetic
—and only for cholesterol
stones. Stones recur after nonsurgical treatment about half the time.
- 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 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 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 very high. Remaining stones can sometimes be dissolved with medication.
Don't People Need Their Gallbladders?
, 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 some people. Also, some studies suggest that removing the gallbladder
may cause higher blood cholesterol
levels, so occasional cholesterol tests may be necessary.
Points To Remember
National Digestive Diseases Information Clearinghouse
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The National Digestive Diseases Information Clearinghouse (NDDIC) is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). NIDDK is part of the National Institutes of Health under the U.S. Department of Health and Human Services. Established in 1980, the clearinghouse provides information about digestive diseases to people with digestive disorders and to their families, health care professionals, and the public. NDDIC answers inquiries; develops, reviews, and distributes publications; and works closely with professional and patient organizations and Government agencies to coordinate resources about digestive diseases.
Publications produced by the clearinghouse are reviewed carefully for scientific accuracy, content, and readability.
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NIH Publication No. 99-2897
e-text posted: January 1999