Primary biliary cholangitis: Understanding a rare liver disease with unusual symptoms

Primary biliary cholangitis (PBC) is a rare autoimmune liver disease characterized by the gradual destruction of small bile ducts within the liver. This process obstructs bile flow, causing cholestasis, chronic inflammation, and progressive fibrosis that can eventually lead to cirrhosis and liver failure.

The immune system mistakenly identifies the body's own cells as a threat, targeting the epithelial cells lining the bile ducts. Most PBC patients have antimitochondrial (AMA) and/or antinuclear (ANA) antibodies, which contribute to the persistent inflammation and liver damage. Professor Piotr Milkiewicz explains that bile's detergent-like properties, essential for digestion, become destructive when trapped in the liver due to cholestasis, damaging bile duct cells and hepatocytes.

Previously termed primary biliary cirrhosis, the disease's name was updated to primary biliary cholangitis to reflect that advanced fibrosis does not always occur. However, timely diagnosis and treatment remain vital. PBC is classified as a rare disease, with global prevalence estimated at 18 cases per 100,000 population and an annual incidence of about 1.8 per 100,000. Unlike many rare diseases diagnosed in childhood, PBC is never diagnosed in children.

While PBC can affect individuals of any age or gender, it predominantly impacts women, accounting for approximately 90% of cases. The average age of diagnosis is around 56, typically falling between 40 and 60 years old. The exact causes are not fully understood but are believed to involve a combination of genetic susceptibility and environmental triggers. Factors such as proximity to toxic waste sites containing heavy metals like cadmium or coal mines have been suggested as potential environmental influences. In Poland, 5,082 patients are currently being treated for PBC, a significant increase from 2015.

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The primary role of bile is to aid in food digestion in the intestine, so it has strong detergent properties, similar to dish soap. If bile cannot flow effectively from the liver due to cholestasis, it begins to 'do its job' within the liver, damaging the bile duct cells first, and then the hepatocytes, which are liver cells.