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Medical Author:

John M. Vierling, MD, FACP

John M. Vierling, MD, FACP

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.

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Medical Editor:

Leslie J. Schoenfield, MD, PhD

Leslie J. Schoenfield, MD, PhD

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.

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In this Article

• What is PBC?
• What is the scope of the problem?
• What is the cause of PBC?
• What are the symptoms and physical findings in PBC?
• What manifestations are specifically due to PBC itself?
• What are the manifestations of the complications of cirrhosis in PBC?
• What are the manifestations of diseases associated with PBC?
• What are risk factors for PBC?
• How is PBC diagnosed?
• What is the role of blood tests?
• What is the role of testing for antimitochondrial antibodies?
• What is the role of imaging tests?
• What is the role of liver biopsy?
• What are the criteria for a definitive diagnosis of PBC
• What is the course of natural progression in PBC?
• What are the sequential clinical phases of PBC?
• What is the role of mathematical models in predicting the outcome (prognosis) in PBC?
• What about pregnancy in PBC?
• Patient Comments: Primary Biliary Cirrhosis - Symptoms
• Patient Comments: Primary Biliary Cirrhosis - Diagnosis
• Find a local Gastroenterologist in your town
• Primary Biliary Cirrhosis Index

Hepatic encephalopathy

The protein in our diet is converted by bacteria normally present in the gut into substances that can alter the function of the brain. When these substances (ammonia, for example) accumulate in the body, they become toxic. Ordinarily, these potentially toxic compounds are carried in the portal vein to the normal liver where they are detoxified.

When cirrhosis and portal hypertension are present, part of the blood flow in the portal vein, as already described, bypasses the liver by flowing through alternative blood vessels. Some of the toxic compounds take this bypass route and, thereby escape detoxification by the liver. The rest of the toxic compounds travel with the rest of the portal blood flow to the liver. However, a damaged liver may be functioning so poorly that it cannot detoxify the toxic compounds present in the portal blood. In this situation, the toxic compounds can go right through the liver and escape detoxification.

Thus, in these two ways, in variable proportions - going around (bypassing) the liver and going right through the liver -- the toxic compounds accumulate in the blood. When the accumulated toxic compounds in the blood stream impair the function of the brain, the condition is called hepatic encephalopathy. Sleeping during the day rather than at night (reversal of the normal sleep pattern) is among the earliest symptoms of hepatic encephalopathy. Other symptoms include irritability, inability to concentrate or perform calculations, loss of memory, confusion, or depressed levels of consciousness. Ultimately, severe hepatic encephalopathy causes coma.

Hypersplenism

The spleen normally acts as a filter removing older red blood cells, white blood cells, and platelets (small particles that help stop bleeding from a cut surface) from the blood. As the portal pressure rises, it increasingly blocks blood flow from the spleen to the liver. The resulting backward pressure in the blood vessels coming from the spleen causes the organ to enlarge (splenomegaly). Sometimes, the spleen is stretched so large that it causes abdominal pain.

As the spleen enlarges, it filters out more and more of the blood elements. Hypersplenism is the term used to describe splenomegaly associated with a low red blood cell count (anemia), low white blood cell count (leucopenia), and/or low platelet count (thrombocytopenia). The anemia can cause weakness, the leucopenia contributes to susceptibility to infections, and the thrombocytopenia can impair the clotting of blood.