|

Autoimmune Hepatitis

Last updated:

Overview

Autoimmune hepatitis (AIH) is a chronic autoimmune disease of unknown aetiology affecting the liver commonly seen in young women. It is associated with circulating autoantibodies, elevated serum IgG and increased serum transaminases.

AIH can be categorised into two main types based on the autoantibodies present:

  • Type 1 AIH – seen in adults and children and is associated with:
    • Antinuclear antibodies (ANA)
    • Anti-smooth muscle antibodies (SMA)
    • Perinuclear anti-neutrophil cytoplasmic autoantibodies (pANCA)
    • Anti-soluble liver antigen (SLA)
  • Type 2 AIH – seen in children only and is associated with:
    • Anti-liver kidney microsomal-1 antibodies (LKM1)

Epidemiology

  • Although AIH affects both sexes in all age groups, it typically affects young and middle-aged women.

Risk Factors

  • Female sex
  • Personal or family history of AIH and/or other autoimmune diseases 

Presentation

The presentation can vary from being asymptomatic to fulminant liver failure. Features may be:

  • Nausea
  • Fatigue
  • Myalgia
  • Pruritus
  • Abdominal discomfort
  • Small joint arthralgia
  • Signs of advanced chronic liver disease (such as ascites, splenomegaly, spider naevi, palmar erythema etc.)

Differential Diagnoses

Primary biliary cirrhosis

  • Fatigue and pruritus are the main presenting complaints and are more pronounced
  • ALP and GGT are raised more than AST and ALT
  • Anti-mitochondrial antibodies are often seen

Primary sclerosing cholangitis

  • The features may overlap but ALP is markedly raised, often more than AST and ALT
  • Strongly associated with ulcerative colitis

Wilson’s disease

  • Although features commonly overlap, neuropsychiatric problems are also present such as speech problems and Parkinsonism
  • Kayser-Fleischer rings may also be seen

Alpha-1-antitrypsin deficiency

  • Patients have features similar to COPD before the development of liver symptoms

Investigations

  • Liver function tests:
    • Bilirubin – mildly increased
    • ALT and AST – elevated, usually up to 300 IU/L, but higher in fulminant hepatitis
    • ALP: mildly increased
    • Gamma-GT: mild increased
    • Albumin: may be decreased if cirrhosis is present
    • Prothrombin time: may be prolonged if cirrhosis is present
  • Serum gamma-globulin:
    • Markedly elevated up to 3 times the upper limit of normal
    • May be normal in some cases
  • AIH autoantibodies:
    • Type 1 AIH autoantibodies:
      • Antinuclear antibodies (ANA)
      • Anti-smooth muscle antibodies (SMA)
      • Perinuclear anti-neutrophil cytoplasmic autoantibodies (pANCA)
    • Anti-soluble liver antigen (SLA)
      • Type 2 AIH autoantibodies:
      • Anti-liver kidney microsomal-1 antibodies (LKM1)
  • Liver biopsy:
    • Essential for diagnosis and evaluating the severity

Management

Overview

Management involves the use of corticosteroids and immunosuppressants such as azathioprine. Liver transplants may also be necessary.

Complications

Prognosis

  • Without treatment, the 5-year survival rate is 50%
  • Cirrhosis develops in up to ½ of patients with AIH 

Author