Autoimmune Hepatitis

Inflammation of the liver caused by an autoimmune condition

Aetiology

  • Increased risk if the patient has another autoimmune disease or first-degree relatives with an autoimmune disease
  • Genetically predisposed individual + exposure to an agent in the environment → autoimmune pathogenic process (exact mechanism unknown)

Pathophysiology

Type I

  • Bimodal age distribution (ages 10-20 and 45-70)
  • More common in females
  • Associated with anti-smooth muscle antibody (ASMA) and sometimes anti-nuclear antibody (ANA)
  • More severe disease associated with soluble liver antigen (SLA)

Type II

  • Children and young adults
  • Associated with liver-kidney microsomal type 1 antibody (LKM-1) and sometimes anti-liver cytosol 1 antibody (anti-LC1)
  • Rare

Clinical presentation

  • Non-specific symptoms - malaise, fever, lethargy, nausea, abdominal pain, anorexia
  • Jaundice
  • Hepatomegaly/splenomegaly (rarely)
  • Advanced disease - stigmata of chronic liver disease

Investigations

LTFs

  • AST/ALT > ALP

Prothrombin time

  • If elevated indicates advancing liver failure

Serology

  • Elevated IgG
  • Autoantibodies
    • Type I ASMA, ANA
    • Type II LMK-1

Biopsy

  • Chronic hepatitis with marked pieces of necrosis and lobular involvement
  • Interface hepatitis
  • Infiltration of plasma cells

Management

  • Prednisolone (higher dose)
  • When symptoms improve reduce dosage and prednisolone and add azathioprine
  • Aim to wean patient off therapy (usually after 2/3 years remission)