Primary Biliary Cirrhosis (PBC)
(Primary Biliary Cholangitis)
(See also Overview of Fibrosis and Cirrhosis of the Liver.)
Primary biliary cirrhosis is inflammation with progressive scarring of the bile ducts in the liver. Eventually, the ducts are blocked, the liver becomes scarred, and cirrhosis and liver failure develop.
Primary biliary cirrhosis probably results from an autoimmune reaction.
This disorder commonly causes itchiness, fatigue, dry mouth and eyes, and jaundice, but some people have no symptoms.
A blood test to measure certain antibodies can usually confirm the diagnosis.
Treatment includes relieving symptoms, slowing liver damage, and treating complications.
Cirrhosis is severe scarring of the liver that destroys the liver’s internal structure and impairs the liver’s ability to regenerate itself and to function. However, people with primary biliary cirrhosis do not actually have cirrhosis when the disorder begins. Cirrhosis develops only after they have had the disorder for some time.
Primary biliary cirrhosis is most common among women aged 35 to 70, although it can occur in men and women of any age. It tends to occur in families.
The liver produces bile, a greenish yellow, thick, sticky fluid that aids digestion. Bile also helps eliminate certain waste products (mainly bilirubin and excess cholesterol) and by-products of drugs from the body. Bile ducts are small tubes that carry bile from the liver to the gallbladder and then to the small intestine. Primary biliary cirrhosis affects only the small bile ducts inside the liver and the liver cells near these bile ducts. Another inflammatory bile duct disorder, primary sclerosing cholangitis, affects bile ducts inside and outside the liver.
Primary biliary cirrhosis begins with inflammation of the bile ducts. The inflammation blocks the flow of bile out of the liver. Thus, bile remains in the liver cells, causing inflammation. As inflammation spreads, a latticework of scar tissue (fibrosis) develops throughout the liver. Scar tissue replaces more and more liver tissue, disrupting the liver's internal structure (causing cirrhosis).
The cause is not clear but is probably an autoimmune reaction (in which the immune system attacks the body’s own tissues). Primary biliary cirrhosis often occurs in people with autoimmune disorders, such as rheumatoid arthritis, scleroderma, Sjögren syndrome, or autoimmune thyroiditis.
An autoimmune cause is also thought possible because more than 95% of people with primary biliary cirrhosis have certain abnormal antibodies in their blood. These antibodies attack mitochondria (tiny structures that produce energy in cells). However, these antibodies are not involved in the destruction of the bile ducts. Other immune cells attack the bile ducts. What triggers this attack is unknown, but it may be exposure to a virus or a toxic substance.
Usually, primary biliary cirrhosis starts very gradually. About half of people have no symptoms at first.
The first symptoms often include
Other problems may not occur until months or years later:
As the disorder progresses, itching may disappear and the yellow bumps may shrink.
Eventually, any of the symptoms and complications of cirrhosis can develop. Fats, including fat-soluble vitamins (A, D, E, and K), are often poorly absorbed. Poor absorption of vitamin D results in osteoporosis, and poor absorption of vitamin K contributes to easy bruising and bleeding. If the body cannot absorb fats, stools may be light-colored, soft, bulky, oily-looking, and unusually foul-smelling (called steatorrhea).
The liver and spleen may enlarge. But as scarring progresses, the liver shrinks.
A doctor may suspect this disorder in middle-aged women who have typical symptoms such as fatigue and itchiness. However, in many people, the disorder is discovered long before symptoms appear because results of routine blood tests to evaluate the liver (liver function tests) are abnormal.
During the physical examination, the doctor may feel an enlarged, firm liver (in about 25% of people) or an enlarged spleen (in about 15%).
If primary biliary cirrhosis is suspected, doctors do liver function tests, imaging tests, and blood tests to check for antibodies to mitochondria.
Imaging tests are done to check for abnormalities or blockages in bile ducts outside the liver. These tests include magnetic resonance imaging (MRI) of the bile duct system (called magnetic resonance cholangiography) and often ultrasonography. If results of these tests are not clear, endoscopic retrograde cholangiopancreatography may be done. For this procedure, an x-ray is taken after a substance that can be seen on x-rays (contrast agent) is injected through a viewing tube (endoscope) inserted through the mouth into the bile ducts. Finding no blockages outside the liver means that the liver is the site of the problem and thus supports the diagnosis of primary biliary cirrhosis.
A liver biopsy (removal of a tissue sample for examination under a microscope) is usually done to confirm the diagnosis. Biopsy also helps doctors determine how advanced the disorder is (the stage).
Primary biliary cirrhosis usually progresses slowly, although how fast it progresses varies greatly. Symptoms may not appear for 2 years or for up to 10 to 15 years. Some people become very ill in 3 to 5 years. Once symptoms develop, life expectancy is about 10 years. Certain characteristics suggest that the disorder will progress quickly:
When itching disappears, the yellow bumps of fat shrink, and jaundice develops, death may occur within months.
There is no known cure. Treatment includes
Drugs to relieve symptoms, primarily itching
Ursodeoxycholic acid to slow the progression of liver damage
Obetacholic acid is a new medication which was approved by the FDA in 2016 for the treatment of PBC. This medication is intended for use in patients in whom ursodeoxycholic acid is not working well.
Treatment of complications
Eventually liver transplantation
No alcohol should be consumed. Drugs that may damage the liver are stopped.
Cholestyramine may control itchiness, as may rifampin, naltrexone (an opioid), sertraline, or ursodeoxycholic acid plus ultraviolet light.
Ursodeoxycholic acid, particularly if used before the disorder is advanced, reduces liver damage, prolongs life, and delays the need for liver transplantation. Obetacholic acid is a newly FDA-approved medication which has been proven to improve liver-related blood tests in many patients with PBC for whom ursodeoxycholic acid alone is not effective.
Supplements of calcium and vitamin D are needed to help prevent osteoporosis or slow its progression. Weight-bearing exercises, bisphosphonates, or raloxifene may also help prevent or slow osteoporosis. Vitamin A, D, E, and K supplements may be needed to correct vitamin deficiencies. Vitamins A, D, and E can be taken by mouth. Vitamin K is given by injection.
Liver transplantation is the best treatment when the disorder is advanced. It can prolong life. After transplantation, primary biliary cirrhosis recurs in some people, but it rarely becomes severe.