Primary biliary cholangitis (PBC) is a common autoimmune disease that primarily affects the small bile ducts within the liver. For uncertain reasons, it is particularly common on Long Island. PBC affects the small bile ducts located within the liver. These small bile ducts connect to a series of progressively larger ducts that facilitate the transport of bile out of the liver. As the damage caused in PBC is to the small bile ducts, one could logically conclude that PBC is a disease of the biliary tree not of the liver. It is important to understand that the ducts which are affected are so small that damage to these bile ducts leads to damage of the liver cells and therefore, PBC is a disease of the liver. In PBC, a slowly progressive inflammatory process destroys the bile ducts within the liver that can lead to cirrhosis.
More than 90 percent of people with PBC are women. Most people with PBC do not have any symptoms and feel fine. There are, however, certain symptoms such as fatigue, itching, joint pains, night blindness, jaundice and skin discolorations are common.
Several diseases are associated with PBC. The prevalence of thyroid disease in PBC is quite high. In fact, the diagnosis of hypothyroidism frequently predates the diagnosis of PBC. Other diseases associated with PBC include dry eyes and dry mouths, scleroderma, osteoarthritis, iritis, celiac disease and myasthenia gravis.
Due to its lack of symptoms, PBC may go unrecognized for years. The most common abnormality leading to the diagnosis of PBC is an isolated elevated liver enzyme called alkaline phosphatase. A positive anti-mitochondrial antibody (AMA) is found in more than 95% of people and confirms the disease. A liver biopsy is not needed to diagnose PBC. Untreated, PBC is a progressive disease and most people will over time progress to more advanced liver disease.
Currently, two drugs are approved for PBC. The first line of therapy of is ursodeoxycholic acid (URSO). URSO works by altering the bile acid concentrations within the liver and modulating the immunologic injury seen in PBC. Treatment is life-long and may prevent disease progression. Although most people respond to URSO, there still remain a few patients who are refractory to this medication. The second line of therapy for patients who do not have a complete response to URSO is obeticholic acid (OCA). OCA is an FXR agonist that decreases bile acid synthesis and increases bile acid secretion causing choleresis.
There is currently a lot of ongoing research to find even more drugs to treat PBC by several different pathways. Hopefully, these new agents will be available in the not too distant future.
In summary, PBC is a common autoimmune disease, which frequently goes unrecognized. Over the past 25 years, progress in the treatment of PBC has led to a change in its natural history from one with a horrible prognosis to an extremely manageable condition. The key is successful treatment is early diagnosis. Appropriate patients should be screened for the disease so that therapy can be initiated early.