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Primary biliary cirrhosis is a disease of the bile ducts
inside the liver. It progresses slowly, so patients may lead
active, productive lives for many years. In PBC, the bile ducts
in the liver become inflamed. The inflammation is chronic
(constant over a long period of time), and causes scaring that
eventually blocks and destroys the bile ducts.
This condition interferes with the proper drainage of bile, so
the bile backs up into the liver and into the bloodstream,
causing various symptoms. Eventually the liver itself becomes
badly damaged and scarred. This is known as cirrhosis.
Cause
The exact cause of PBC is unknown.
Scientists believe there could be more than one contributing
factor. While it does not have the traits of an inherited
disease, it does appear more often in some families. People with
PBC sometimes have a history of allergies or autoimmune
disturbances-that is when the body's immune system recognizes
a part of the body as foreign and injures or goes to war against
it. Rheumatoid arthritis and lupus are examples of autoimmune
disorders.
Symptoms
PBC occurs in both men and women, but women get the disease 10
times more often than men. It usually begins between the ages of
30 and 60. Early in the disease, many patients have no symptoms.
The only findings may be abnormal blood laboratory results. For
example, a high level of the liver enzyme called alkaline
phosphatase may be found in the blood. Itching and fatigue are
common symptoms later in the disease. Itching is caused by bile
entering the bloodstream.
As PBC progresses, other symptoms occur. There may be jaundice
(yellowing of skin and eyes from excess bile in the blood),
cholesterol deposits in the skin, fluid accumulation or edema,
and darkening of the skin. Other immune related problems may also
be present. For example, the tear and salivary glands may not
function properly, causing dry eyes and mouth. Arthritis and
thyroid problems may be present, and osteoporosis can develop in
later stages. The bones become soft and fragile, leading to
increased risk of fractures. The development of cirrhosis is the
end result of PBC.
Diagnosis
PBC diagnosis is based on several pieces of information.
Itching and fatigue alert the physician that bile ducts may be
damaged. As previously mentioned, high levels of certain liver
enzymes in the blood are important clues.
Probably the most important laboratory test is one for
mitochondrial antibodies. Mitochondria are the energy sources
within cells. For unknown reasons a protein antibody develops
against them in 95 percent of PBC cases. The physician must took
at the whole picture to make the diagnosis of PBC.
Often the physician x-rays the bile ducts to rule out other
causes of obstruction. This x-ray, called an ERCP, is performed
under light sedation. A lighted, flexible endoscope is inserted
through the mouth, stomach, and then into the small intestine. A
thin tube is placed through the scope into the bile ducts, and
dye is injected to highlight the bile ducts on the x- ray.
As the disease progresses, a liver biopsy is needed to
determine how much damage has occurred. Under local anesthesia, a
slender needle is inserted through the right lower chest to
extract a small piece of liver for microscopic analysis.
Treatment
Because PBC advances slowly, patients often have no symptoms
for many years. Initial treatment for PBC is aimed at reducing
symptoms when they occur. Itching can be controlled by drugs such
as Questran. Bile is usually reabsorbed into the bloodstream from
the large intestine, and goes back to the liver to be reused.
Questran binds up bile in the intestine, allowing it to be
eliminated with the stool instead. This helps to reduce the
build-up of bile in the body.
The diet should be well-balanced. At least 1,200 mg of calcium
per day is needed to prevent osteoporosis. Also, if blood levels
of vitamin D are below normal, the physician may prescribe a
supplement. Vitamin D helps the body absorb calcium from the
intestine. If thyroid function is low, it too can be treated with
medication. Diuretics (fluid pills) and reducing salt intake can
help reduce edema or swelling.
Some drugs seem to improve liver function blood tests. Some
research studies suggest these drugs reduce damage to the liver.
Actigall changes the make-up of bile in the liver and seems to
reduce liver damage. Colchicine is an older drug that may reduce
scar formation in the liver. Another drug that shows promise is
methotrexate (trade name Rheumatrex). It suppresses the immune
response in the body. When PBC progresses to a point where too
much liver damage has occurred, liver transplantation must be
considered.
Liver Transplantation
Liver transplantation is now an accepted form of treatment for
chronic, severe liver disease. Advances in surgical techniques
and the use of new drugs to suppress rejection have improved the
success rate of transplantation. The outcome for PBC patients is
excellent. Because of the disease's slow progress, it is
possible to plan elective transplant surgery. Survival rates at
transplant centers are well over 90 percent, with a good quality
of life after recovery.
Summary
Primary biliary cirrhosis is a slow, progressive. disease.
Once diagnosed, treatment is directed at managing symptoms and
slowing down liver damage. A great deal of research is underway
aimed at discovering the cause, preventing damage to the bile
ducts and liver, improving symptoms, and prolonging life.
Transplantation is now a standard form of treatment for advanced
disease. By working closely with the physician, there is good
reason to expect a favorable long-term outlook.
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