Autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory liver disease which, untreated, often leads to cirrhosis.

 Presentation
  • 25% asymptomatic at diagnosis
  • Others:
    • fatigue
    • pruritis
    • anorexia
    • nausea
    • abdominal pain
    • joint pain

Associations
  • long-term use of some medications, such as nitrofurantoin or minocycline
  • primary biliary cirrhosis - up to 15%
  • primary sclerosing cholangitis - up to 8%
  • thyroiditis - up to 23%
  • diabetes - up to 9%

Investigations
  • LFTs - raised AST/ALT
  • autoantibodies
    • ANA
    • SMA
    • SLA/LP (soluble liver antigen/liver-pancreas)
    • LKM (liver-kidney microsome)
    • dsDNA - 15% (specific for either AIH or SLE)
  • raised IgG
  • negative tests for viral hepatitis
  • liver biopsy may show
    • lots of plasma cells - 'plasma-cell hepatitis'
    • inflammation of hepatocytes at the junction of portal tract and hepatic parenchyma - 'piecemeal necrosis'

Types of AIH:
  • Type 1
    • 75% of AIH
    • ANA/SMA/anti SLA/LP
    • all ages
    • F:M 3:1
  • Type 2
    • anti-LKM-1 or anti LC-1
    • usually presents in childhood
    • F:M 10:1
    • more likely to not respond to treatment
Treatment
  • corticosteroids
  • azathioprine
  • lifelong in type 2 AIH; can consider stopping after remission of at least 4 years in type 1 AIH 
  • 10-20% of patients will need liver transplants.

Small print gems: In terms of liver diseases, raised IgG suggests AIH, IgM suggests PBC and IgA suggests steatohepatitis (alcoholic or non-alcoholic)


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