What do I have?
Primary Biliary Cirrhosis (PBC)
What is it?
Primary biliary cirrhosis is a disease in which the bile ducts in your liver are slowly destroyed. Bile, a fluid produced in your liver, is essential for the proper digestion of fats. It also helps rid your body of worn-out red blood cells, cholesterol and toxins. In primary biliary cirrhosis, the destruction of your bile ducts can cause harmful substances to build up in your liver and sometimes lead to irreversible scarring of liver tissue (cirrhosis).
The cause of primary biliary cirrhosis remains unclear. Many experts consider primary biliary cirrhosis an autoimmune disease in which the body turns against its own cells, although it's likely that genetic and environmental factors also play a part. Primary biliary cirrhosis develops slowly. Medication can slow the progression of the disease, especially if treatment begins early
What does the disease do to your body?
The problems in primary biliary cirrhosis begin with inflammation in the smallest ducts in your liver. In time, the inflammation spreads to and destroys nearby liver cells. As these cells are destroyed, they're replaced by scar tissue (fibrosis). Over a period of years, the combination of ongoing inflammation, scarring and toxicity from trapped bile can lead to cirrhosis. Cirrhosis involves irreversible scarring of liver tissue that makes it impossible for your liver to carry out essential functions.
The inflammation begins when T lymphocytes (T cells) begin accumulating in your liver. T cells are white blood cells that are part of your immune system response. Normally, T cells recognize and help defend against bacteria and fungi. But in primary biliary cirrhosis, the T cells invade and destroy the cells lining the small bile ducts. The T cells also produce chemicals that stimulate liver cells to secrete proteins that attract more T cells, thereby creating an ongoing cycle of damage.
Researchers suspect that a genetic susceptibility coupled with an environmental trigger, such as infection, may be at the root of this abnormal immune response:
- Genetics. Primary biliary cirrhosis seems to run in families, and scientists believe that some people may inherit certain immune system defects that make them more susceptible to the disorder. Research has identified three genetic variations associated with primary biliary cirrhosis. This finding may eventually help researchers narrow in on the cause of primary biliary cirrhosis.
- Infection. For decades, researchers have suspected that primary biliary cirrhosis might result from a bacterial, fungal or parasitic infection, which would explain the massing of T cells in the small bile ducts. Some women reported having urinary tract infections, primarily those caused by the Escherichia coli bacterium, prior to the development of primary biliary cirrhosis. However, no commonplace infections have yet been consistently linked to primary biliary cirrhosis.
As liver damage progresses, people with primary biliary cirrhosis may develop a number of serious problems, including:
- Cirrhosis. The term "primary biliary cirrhosis" isn't entirely accurate because cirrhosis develops only in the later stages of the disease — often many years after diagnosis. Yet when it does occur, cirrhosis can be life-threatening because it interferes with your liver's ability to carry out essential functions. Cases of primary biliary cirrhosis are divided into four stages. The first stage — inflammation of the bile ducts — is the least serious, and stage 4 — cirrhosis — the most serious. Ongoing cirrhosis can lead to liver failure, which occurs when your liver is no longer able to function.
- Increased pressure in the portal vein (portal hypertension). Blood from your intestine, spleen and pancreas enters your liver through a large blood vessel called the portal vein. When scar tissue blocks normal circulation through your liver, blood backs up, much like water behind a dam, leading to increased pressure within the vein. And because blood doesn't flow normally through your liver, hormones, drugs and other toxins aren't filtered properly before entering your bloodstream.
- Enlarged veins (varices). When circulation through the portal vein is slowed or blocked, blood may back up into other veins — mainly those in your stomach and esophagus. The blood vessels are thin walled, and increased pressure in your veins can cause bleeding in your upper stomach or esophagus. This bleeding is a life-threatening emergency that requires immediate medical care.
- Liver cancer. The destruction of healthy liver tissue that occurs in cirrhosis increases your risk of liver cancer.
- Weak bones (osteoporosis). Liver scarring interferes with your liver's ability to process vitamin D and calcium, both of which are essential for bone growth and health. As a result, weak, brittle bones and bone loss may be complications of late-stage primary biliary cirrhosis, and your doctor may order a bone density test to look for osteoporosis.
- Vitamin deficiencies. A lack of bile affects the absorption of fats and of the fat-soluble vitamins, A, D, E and K. This sometimes leads to deficiencies of these vitamins in advanced cases of primary biliary cirrhosis.
- Cognitive impairment. Some people with primary biliary cirrhosis have problems with memory and concentration. Cognitive difficulties don't seem to correlate directly to the amount of liver damage, however.
Treatments aimed at slowing the disease and prolonging life include:
- Ursodeoxycholic acid (UDCA). Also known as ursodiol (Actigall), UDCA is a bile acid that helps move bile through your liver. Although UDCA doesn't cure primary biliary cirrhosis, it may prolong life if started early in the disease and is commonly considered the first line of therapy. It's less likely to help people with advanced liver damage. Side effects of UDCA may include weight gain, hair loss and diarrhea.
- Other drugs. Sometimes other drugs are used off-label or in clinical trials to treat primary biliary cirrhosis, but many have proved to have serious side effects or haven't been effective. For example, some studies show that the drug methotrexate, which is normally used to treat arthritis, psoriasis and some types of cancer, isn't helpful in primary biliary cirrhosis, whereas others show it to be somewhat effective.
- Liver transplant. When treatments no longer control primary biliary cirrhosis and the liver begins to fail, a liver transplant may help prolong life. People with primary biliary cirrhosis who have liver transplants often do very well, although the disease may recur in the new liver.
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