Definition: Primary biliary cirrhosis, sometimes referred to as PBC, is a disease in which the intrahepatic bile ducts are slowly damaged. Bile is a fluid produced by the liver that is important for food digestion and helps remove aging red blood cells, cholesterol and toxins from the body. As in primary biliary cirrhosis, when the bile ducts are damaged, harmful substances can accumulate in the liver, sometimes leading to irreversible scarring of the liver tissue (cirrhosis). Primary biliary cirrhosis is generally considered to be an autoimmune disease, in which the body reacts immunologically to its own cells. Researchers believe that primary biliary cirrhosis is caused by a combination of genetic and environmental factors. Primary biliary cirrhosis usually progresses slowly, and medications can slow the disease process, especially if treated early. Although some patients with primary biliary cirrhosis remain asymptomatic for several years after diagnosis, some patients will develop a range of signs and symptoms. Early symptoms usually include: 1. fatigue; 2. itchy skin; and 3. dry eyes and mouth. Later signs and symptoms may include: 1. pain in the right upper abdomen; 2. pain in the bones, muscles or joints (skeletal muscle system); 3. yellowing of the skin and eyes (jaundice); 4. darkening of the skin color not associated with sun exposure (hyperpigmentation); 5. swelling of the feet and ankles (edema); 6. fluid accumulation in the abdomen due to liver failure (ascites); 7. wrinkling of the eyes, skin around the eyelids or palms of the hands, lipid deposits in the skin around the eyes and eyelids or in the folds of the palms of the feet, elbows or knees (xanthomas); 8. weak and brittle bones (osteoporosis), prone to fractures; 9. elevated cholesterol; 10. diarrhea, with stools that may contain more fat (steatorrhea). Hypothyroidism (hypothyroidism) The etiology of primary biliary cirrhosis is not clear. Many experts believe that primary biliary cirrhosis is an autoimmune disease, in which the body reacts immunologically to its own cells.