Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic autoimmune disease affecting the liver.

Pathophysiology

Current understanding of PBC states that a certain environmental trigger such as cigarette smoke leads to an immune response in genetically susceptible individuals i.e. the pathogenesis is multifactorial. This immune response results in damage to intrahepatic bile duct cells, which with time causes obstruction and cholestasis. Cholestasis can lead to fibrosis, portal hypertension and cirrhosis.

PBC is strongly associated with the presence of autoantibodies, namely anti-mitochondrial antibodies (AMA) which are thought to be present in around 85% of cases. Other antibodies which may be present include anti-multiple nuclear dot antibody (anti-MND) and anti-nuclear antibody (ANA).

Clinical Features

• Tends to affect women more than men, usually between 30 and 60
• Usually asymptomatic and diagnosed from an incidentally abnormal liver function test
• Fatigue
• Pruritus
• Jaundice
• History of hypercholesterolaemia
• Xanthelasma
• Fat soluble vitamin deficiency
• Hepatomegaly
• Splenomegaly
• Signs of chronic liver disease

Associated Conditions

PBC is associated with other autoimmune diseases including Sjögren’s syndrome, Hashimoto’s thyroiditis, coeliac disease and rheumatoid arthritis.

Investigations

Bloods

• Alkaline phosphatase: Usually 1.5x higher than the upper limit of normal
• Gamma-GT: Also raised (in keeping with cholestatic picture)
• AST and ALT: Can be moderately raised
• AMA: Commonly positive but other autoantibodies may be present such as ANA

Imaging

• Abdominal ultrasound: Exclude an obstructive, extra-hepatic lesion that could be causing the cholestasis
• Magnetic resonance cholangiopancreatography (MRCP)

Management

Ursodeoxycholic acid (UDCA) is the main treatment option for individuals with PBC – one of the most major side effects of this treatment is weight gain.

Management of symptoms is also important e.g. cholestyramine for pruritus. Treatment for end-stage PBC is with liver transplant considering patients may well develop complications of long-term liver disease such as cirrhosis. 

References

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2095651/

https://www.nhs.uk/conditions/primary-biliary-cirrhosis-pbc/treatment/

https://www.ncbi.nlm.nih.gov/books/NBK459209/