Primary Biliary Cirrhosis
Primary biliary cirrhosis is inflammation and eventual scarring and obstruction of the bile ducts inside the liver.
Primary biliary cirrhosis is most common among women aged 35 to 60, though it can occur in men and women of any age. The cause, though not clear, is probably autoimmune; the person's immune system attacks the body's own tissues (see Section 16, Chapter 186). Primary biliary cirrhosis occurs in association with rheumatoid arthritis, scleroderma, or autoimmune thyroiditis. Unlike primary sclerosing cholangitis, primary biliary cirrhosis affects only the bile ducts inside the liver.
Primary biliary cirrhosis begins with inflammation of the bile ducts inside the liver. The inflammation blocks the flow of bile (the greenish yellow digestive fluid) out of the liver; thus, bile remains in the liver cells or spills over into the bloodstream. As inflammation spreads from the bile ducts to the rest of the liver, a latticework of scar tissue develops throughout the liver.
Symptoms and Diagnosis
Usually, primary biliary cirrhosis starts gradually. Itchiness and sometimes fatigue are often the first symptoms. Other features, which may not occur until months or years later, include enlargement of the tips of the fingers (clubbing) and abnormalities of the bone, nerves, and kidney. The stool may be pale and greasy and have an unusually offensive odor (steatorrhea). Later, any of the symptoms and complications of cirrhosis can develop (see Section 10, Chapter 136). Metabolic bone disease (osteoporosis) develops in most people.
On physical examination, a doctor feels an enlarged, firm liver in about 50% of people and an enlarged spleen in about 25%. In the late stages, the scarred liver shrinks in size. About 15% of people have small yellow deposits in the skin (xanthoma) or eyelids (xanthelasma). About 10% have increased skin pigmentation. Fewer than 10% have only jaundice (a yellowish discoloration of the skin and the whites of the eyes) early on; jaundice tends to develop in others later.
In about 50% of people with primary biliary cirrhosis, the disorder is discovered before symptoms even develop because of abnormalities detected during routine blood testing. Antibodies against mitochondria (tiny structures contained within cells) are found in the blood of more than 90% of people with the disorder.
When jaundice is evident or results of liver function tests indicate abnormalities, an ultrasound scan, or occasionally an MRI of the bile duct system (magnetic resonance cholangiogram) can be used to show any abnormalities or obstruction of the bile ducts outside the liver. The diagnosis of primary biliary cirrhosis is supported by finding that the bile ducts outside the liver are unobstructed, thus identifying the liver as the site of the problem. Finding antibodies against mitochondria clinches the diagnosis. A liver biopsy (removal of a tissue sample for examination under a microscope (see Section 10, Chapter 134)) confirms the diagnosis and stages the disease (such as early or late with cirrhosis established).
Prognosis and Treatment
The progression of primary biliary cirrhosis varies greatly. People who initially have no symptoms often develop symptoms after 2 to 7 years. Others have virtually no symptoms for 10 to 15 years. Still others become very ill in 3 to 5 years. The disorder eventually culminates in severe cirrhosis. The outcome is poor for people who develop jaundice.
No cure is known. The drug cholestyramine may control itchiness. Supplements of calcium and vitamins A, D, and K in a water-soluble form may be needed, because the natural forms of these nutrients are fat-soluble and are therefore not properly absorbed from the intestine when there is insufficient bile. The drug ursodeoxycholic acid appears to somewhat lessen the progression of the disorder and is generally well tolerated. Liver transplantation (see Section 16, Chapter 187) is the best treatment for people entering the final stages of the disorder.
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