|
Young Choi, M.D. & William B. Silverman, M.D.
FACG, Division of GI/Hepatology,
University of Iowa Hospitals and Clinics, Iowa City, Iowa
What are Gallstones?
Gallstones are collections of cholesterol, bile pigment or
a combination of the two, which can form in the gallbladder
or within the bile ducts of the liver. In the United States,
the most common type of gallstones is made of cholesterol.
Cholesterol stones form due to an imbalance in the production
of cholesterol or the secretion of bile. Pigmented stones
are primarily composed of bilirubin, which is a chemical produced
as a result of the normal breakdown of red blood cells. Bilirubin
gallstones are more common in Asia and Africa but are seen
in diseases that damage red blood cells such a sickle cell
anemia.
How Do Gallstones Cause Problems?
If gallstones form in the biliary system they can cause blockage
of the bile ducts, which normally drain bile from the gallbladder
and liver. Occasionally the gallstones can also block the
flow of digestive enzymes from the pancreas since both the
bile ducts and pancreas ducts drain through the same small
opening (called the Ampulla of Vater) which is held tight
by a small circular muscle (called the Sphincter of Oddi).
[See diagram below]. This results in inflammation of the pancreas.
This is known as gallstone pancreatitis. Blockage of the bile
ducts may cause symptoms such as abdominal pain, nausea and
vomiting. If the bile duct remains blocked bile is unable
to drain properly, jaundice (yellow discoloration of the eyes
and skin) can develop and an infection known as cholangitis
may also develop.
Figure 1: Anatomy of liver, bile duct, pancreas
duct and sphincter of Oddi. Note that a stone can impact at
the sphincter of Oddi and block both the bile duct and pancreas
duct.
Who Is at Risk for Gallstones?
Female gender, older age, obesity, high cholesterol levels,
treatment with estrogen containing medications, rapid weight
loss, diabetes and pregnancy are all risk factors for developing
cholesterol gallstones. Disorders that lead to the destruction
of red blood cells such as sickle cell anemia are associated
with the development of pigmented or bilirubin stones. The occurrence
of gallstones varies widely among different ethnic groups. For
example, Pima Indians and Hispanics have high occurrence rates
of developing gallstones compared to Asians, who overall, have
a very low rate.
What Are the Symptoms of Gallstones?
Gallstones that are not causing symptoms generally do not
cause problems and do not require further evaluation. Many
times gallstones are found by chance on an abdominal x-ray
or ultrasound done for other reasons. Unless symptoms of pain,
nausea, vomiting or fever are present, no additional testing
or intervention may be needed. Symptoms arise when a gallstone
blocks the flow of bile out of the gallbladder or through
the bile ducts. A gallstone in the common bile duct is called
choledocholithiasis and may cause intermittent or constant
discomfort. The pain of choledocholithiasis is usually localized
in the upper abdomen, and can radiate (be felt in another
location) in the right shoulder, may last many minutes to
hours, and be associated with sweating, nausea, vomiting,
and. Gallstone attacks can produce chest pain that may feel
like a heart attack. If a pain is new and different than other
pains the symptoms should be discussed with a physician.
An inflamed gallbladder (cholecystitis), infected material
trapped within the common bile duct (cholangitis), or a stone
blocking outflow of pancreatic juice (gallstone pancreatitis)
can result in fever, chills, severe abdominal pain or jaundice.
Individuals with these complaints should have an urgent evaluation
by a physician.
How Are Gallstones Diagnosed?
The diagnosis of gallstones is suspected when symptoms of
right upper quadrant abdominal pain, nausea or vomiting occur.
The location, duration and “character” (stabbing,
gnawing, cramping) of the pain help to determine the likelihood
of gallstone disease. Abdominal tenderness and abnormally
high liver function blood tests may be present. An abdominal
ultrasound examination is a quick, sensitive, and relatively
inexpensive method of detecting gallstones in the gallbladder
or common bile duct. This is the test most often used.
What is the Treatment for Gallstones?
The treatment for gallstones that obstruct the common bile
duct is endoscopic retrograde cholangiopancreatography (ERCP)
or surgery. ERCP involves passage of a thin flexible scope
through the mouth and into the duodenum where it is used to
evaluate the common bile duct or pancreatic duct. Tiny tubes
and instruments may be used to further evaluate the ducts
and remove stones if necessary. Gallbladder surgery may be
performed if there are stones found in the gallbladder itself,
as these cannot be removed by ERCP. This operation, known
as cholecystectomy, is frequently done using a laparoscope,
another thin scope that resembles an endoscope, and is inserted
into the abdomen through several small incisions under general
anesthesia. If a gallbladder operation is not possible, a
medicine known as ursodiol, may be used to dissolve cholesterol
gallstones but this can take months, and the stones recur
in many people once the treatment is stopped.
Gallstone pancreatitis is inflammation of the pancreas that
results from blockage of the pancreas duct by a gallstone.
This occurs at the level of the sphincter of Oddi, a round
muscle located at the opening of the bile duct into the small
intestine. If a stone from the gallbladder should travel down
the common bile duct and get stuck at the sphincter, it blocks
outflow of all material from the liver and pancreas. This
results in inflammation of the pancreas that can be quite
severe. Gallstone pancreatitis can be a life-threatening disease
and evaluation by a physician urgently is needed if someone
with gallstones suddenly develops severe abdominal pain.
Who Gets Gallstone Pancreatitis?
Risk factors for gallstone pancreatitis are similar to those
described for gallstone disease.
What Are the Symptoms of Gallstone Pancreatitis?
Symptoms may be similar to those discussed above in Gallstones
and Gallstone Disease. Additionally, the pain may
be felt in the left upper abdomen or in the back. It is usually
sudden in onset, quite severe, frequently sharp or squeezing
in character, and often associated with nausea and vomiting.
How Is Gallstone Pancreatitis Diagnosed?
Blood tests can identify inflammation of the pancreas (amylase
and lipase) and evidence of obstructed outflow of bile from
the liver (ALT, AST, alkaline phosphatase and bilirubin).
Inflammation of the pancreas is best demonstrated by an abdominal
CAT scan, which can also determine the severity of the pancreatic
inflammation. CT scans are not as sensitive at identifying
small gallstones and an abdominal ultrasound may be ordered
if this is considered the cause of the pancreatitis
What is the Treatment of Gallstone Pancreatitis?
Pancreatitis is best treated initially by avoiding any intake
of liquids and solids until the inflammation subsides. Intravenous
delivery of fluids is usually all that’s required if
the inflammation is modest and symptoms resolve in a few days.
Severe inflammation, persistent pain or fevers suggest severe
pancreatitis and ongoing inflammation. Intravenous delivery
of nutrients would be started if oral intake cannot be restarted
within approximately 5-7 days. Severe nausea and vomiting
are treated initially by relieving the stomach of fluid by
use of a nasogastric tube and with antinausea medications.
Pain therapies may be administered by intravenous until oral
treatments and food intake can resume. Sometimes it is important
to remove a gallstone causing pancreatitis urgently, and other
times it may be appropriate to wait 24-48 hours with regular
assessments to assure the individual remains stable. Stones
that cause gallstone pancreatitis may pass out of the duct
without intervention or may require endoscopic or surgical
removal. In cases of infected pancreatic tissue, or a condition
called pancreatic necrosis (dead tissue) occurs, antibiotics
may be used to control or prevent infection.
What Is Sphincter of Oddi Dysfunction?
Sphincter of Oddi Dysfunction (SOD) is a symptom complex
of intermittent upper abdominal pain that may be accompanied
by nausea and vomiting. This disorder is not completely understood.
It is thought to be caused by either scarring or spasm of
the sphincter of Oddi muscle. The sphincter of Oddi muscle
is a small circular muscle approximately ½ inch in
length, located at the downstream end of the bile duct and
pancreas duct. The function of this muscle is to keep the
bile duct and pancreatic duct muscles closed and, therefore,
prevent reflux of intestinal contents into the bile duct and
pancreas duct. If this muscle should spasm or scar, drainage
of the bile duct and/or pancreas duct may be hindered. Abnormal
dilation of the bile duct and/or pancreas duct is often associated
with an increase in the products and enzymes made by the liver,
gallbladder and pancreas, which can be tested for with blood
tests (serum liver tests, amylase, lipase). If the ducts are
blocked this may result in pain.
Who Gets SOD?
Biliary dyskinesia may develop after the gallbladder has
been removed, hence the name post-cholecystectomy syndrome.
What Are the Symptoms of SOD?
Symptoms may be similar to those for which the gallbladder
was initially removed and include abdominal pain, nausea and
vomiting. The symptoms may be episodic. They may wax and wane.
Subjects may experience weight loss due to poor appetite.
Fever, chills and diarrhea are not characteristic of this
disease. If symptoms are severe and do not respond to conservative
treatment, further investigation may be warranted.
What Establishes a Diagnosis of SOD?
It is important to verify that other, more serious conditions
are not being missed prior to embarking on a diagnosis of
sphincter of Oddi dysfunction. Therefore, it would be important
to verify that the patient does not have stones within the
bile ducts, cancer of the pancreas or bile ducts, peptic ulcer
disease or heart disease (poor blood flow to the heart, called
“ischemia” or “angina” may mimic these
symptoms).
The diagnosis of sphincter of Oddi dysfunction can be evaluated
and confirmed using a special endoscope that allows the placement
of a catheter into the bile and pancreatic ducts. Injection
of contrast through the catheter coupled with the use of X-rays
can give the physician pictures of the bile and pancreatic
ducts. The procedure, that requires a special scope is known
as an endoscopic retrograde cholangiopancreatography (ERCP).
This procedure can help determine the presence of gallstones
in the gall bladder or bile duct. In the case of bile duct
stones, special instruments and procedures (sphincterotomy
with stone extraction) (see figure 2, above) can be used at
the time of ERCP to remove the vast majority of them. Measurements
of the contracting force of the sphincter of Oddi muscle can
be made using a special plastic tube inserted into the bile
duct or pancreas duct at the level of the sphincter of Oddi
muscle. This is called “sphincter of Oddi manometry”
and is used to determine if the muscle is “dyskinetic”
or contracts abnormally. If it does, a diagnosis of biliary
dyskinesia is confirmed.
What Is the Treatment of SOD?
In patients with severe symptoms that cannot be tolerated,
the sphincter muscle may be cut open using the ERCP scope
and a special plastic tube with a small wire attached to the
side (called a “sphincterotome”). The sphincterotome
is passed through the ERCP scope channel, then into the bile
duct and/or pancreas duct at the level of the sphincter muscle.
A small electric current is then applied to the wire, which
then cuts and cauterizes the open muscle. This is called “sphincterotomy”.
This procedure should only be done by highly experienced doctors
and only when symptoms are severe and do not resolve. Approximately
5-15% of patients who undergo this therapy may develop inflammation
of the pancreas (called “pancreatitis”) as a complication
immediately following this procedure.
Tests Used to Evaluate for Gallstone
Disease:
- Ultrasound – This test uses sound
waves to examine the bile ducts, liver and pancreas. It
is very safe. Stones may be seen in the gallbladder or bile
ducts. Imaging may be hindered in patients who are very
obese or have recently eaten food.
- Endoscopic Ultrasound – This device
uses a special scope with an ultrasound probe on the end.
The scope is passed down into the intestines where the bile
ducts, gallbladder, and pancreas ducts can be examined internally
rather then externally. Use of the endoscopic ultrasound
device requires special training. It is helpful in locating
bile duct stones that may be missed by ordinary ultrasound.
It is also helpful in diagnosing cancers within the pancreas
and bile ducts.
- CT Scan – It is helpful in diagnosing
cancers within the liver and pancreas. It may identify gallstones
but is not as effective in finding them as ultrasound. It
is the one of the better tests to assess the severity of
pancreatitis.
- ERCP – ERCP (Endoscopic Retrograde
Cholangiopancreatography). This is a special type of endoscope,
which allows access to the bile ducts and pancreas ducts.
It also allows therapy to be performed such as removing
stones from the bile ducts or pancreas ducts. Measurement
of pressure within the sphincter of Oddi muscle may be performed
by an additional test called sphincter of Oddi manometry
(see section on Biliary Dyskinesia). This is done at the
time of ERCP. It is a specialized test requiring special
training.
- MRCP - (Magnetic Resonance Cholangiopancreatography).
This test uses a machine called MRI (Magnetic Resonance
Imaging). It is a noninvasive test that employs special
computer software to create images of the bile and pancreatic
ducts similar to the ones obtained by ERCP and does not
require an endoscopy. Abnormalities found on MRCP would
be further evaluated or treated by ERCP or surgery.
|
