John M. Vierling M.D. is Professor of Medicine and Surgery at the Baylor College of Medicine in Houston, Texas, where he also serves as Director of Baylor Liver Health and Chief of Hepatology. In addition, he is the Director of Advanced Liver Therapies, a center devoted to clinical research in hepatobiliary diseases at St. Luke's Episcopal Hospital. Dr. Vierling is board certified in internal medicine and gastroenterology and a Fellow of the American College of Physicians.
Dr. Schoenfield served as associate professor of medicine and consultant in gastroenterology on the faculty of the Mayo Clinic for seven years. He became a professor of medicine in residence at UCLA from 1972 to 1999 (now emeritus). He was the director of gastroenterology at Cedars-Sinai Medical Center in Los Angeles for 25 years, where he received the chief resident's teaching award, the president's award, and the pioneer of medicine award.
PBC is a chronic disease characterized by progressive inflammation and destruction of small bile ducts within the liver. The bile ducts transport bile from the liver to the intestine for the absorption of fat and elimination of waste products.
A disease of adults, PBC affects 10 women for every man. The number of adults with PBC is now estimated to be 25 to 335 per million women and 2.8 to 37 per million men, and is probably increasing.
The cause of PBC may involve autoimmunity, infection, or genetic predisposition, acting alone or in combination. The finding of autoantibodies called antimitochondrial antibodies (AMA) in 95-98% of patients with PBC favors the concept of an autoimmune disease occurring in genetically predisposed individuals.
The symptoms and physical findings in patients with PBC can be divided into those due to the PBC itself, the complications of cirrhosis in PBC, and the diseases associated with PBC.
The risk of developing PBC is significantly greater for people who have had other autoimmune diseases, smoked cigarettes, had a tonsillectomy as a child, or for women who have had urinary tract or vaginal infections.
The criteria for a definitive diagnosis of PBC include the presence of cholestatic liver blood tests, a positive AMA with a titer equal to or greater than 1:40, and a liver biopsy consistent with the diagnosis.
The natural history of untreated PBC extends for decades and goes through four phases. Sequentially, there is a pre-clinical phase with a positive AMA in the absence of liver blood test abnormalities or symptoms, an asymptomatic phase when liver tests become abnormal, a symptomatic phase, and an advanced phase with the complications of cirrhosis.
The outcome (prognosis) of individual patients can be estimated using a mathematical equation to calculate a Mayo risk score.
Pregnancy occurs infrequently in women with PBC, but most pregnant women with PBC have delivered normal babies. The chance that treatment with ursodeoxycholic acid during pregnancy will cause fetal harm is remote but possible.
Medications used to treat PBC itself include most commonly ursodeoxycholic acid (UDCA), rarely colchicine, and sometimes certain immunosuppressive medications, such as corticosteroids. The UDCA is the most effective and safe treatment.
Treatments are also available for the symptoms of PBC including itching, osteoporosis, elevated serum cholesterol and xanthomas, and malabsorption of fat and the fat-soluble vitamins A, D, E, and K.
PBC patients with advanced complications of cirrhosis, severe osteoporosis, or intractableitching are eligible for liver transplantation. The results of liver transplantation are excellent in patients with PBC.
The goal of research in PBC is to better understand the ways in which the inflammation that destroys small bile ducts and later produces cirrhosis is initiated and perpetuated. More research funding from both the public and private sectors is necessary to achieve results that lead to more effective therapies.