Pathophysiology
Clinical meaning
Primary biliary cholangitis (PBC, formerly primary biliary cirrhosis) is a chronic autoimmune liver disease characterized by progressive destruction of small intrahepatic bile ducts by T-cell-mediated granulomatous inflammation. Anti-mitochondrial antibodies (AMA), particularly against the E2 component of pyruvate dehydrogenase complex (PDC-E2) on the inner mitochondrial membrane, are present in 95% of patients and are highly specific. Progressive bile duct destruction leads to cholestasis (bile salt retention), which damages hepatocytes through detergent-like toxic effects of accumulated bile acids, stimulates fibrosis, and eventually progresses to biliary cirrhosis. Clinical features include fatigue (the most debilitating symptom), pruritus (from bile salt deposition in skin), jaundice, xanthomas (cholesterol deposits), and complications of chronic cholestasis (fat-soluble vitamin deficiency -- A, D, E, K -- causing night blindness, osteoporosis, neuropathy, and coagulopathy). The nurse monitors liver function tests (alkaline phosphatase and GGT are characteristically elevated), monitors bilirubin trends (prognostic marker), administers ursodeoxycholic acid (UDCA, first-line therapy that slows disease progression by displacing toxic bile acids), manages pruritus (cholestyramine, rifampin), monitors for complications of cirrhosis, supplements fat-soluble vitamins, assesses bone density, and coordinates liver transplant evaluation for progressive disease.