Medical Musing of the Week: Autoimmune Hepatitis

Overview

  • AIH is a chronic disease of unknown etiology marked by hepatocellular damage, inflammation and necrosis
  • 3 Subtypes: AIH 1, AIH 2, AIH 3 (2 is the most common!)

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Etiology

  • Unknown
  • Potential post viral (EBV, Hep A, Hep B or Measles)
  • Toxin exposure (Macrobid, Minocycline, Infliximab

Pathophysiology

  • Genetic predisposition w/ environmental triggers
  • Cell mediated immunologic attack
  • High serum globulin concentration
  • Potential alterations of T and B cell function

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Risk Factors

  • Women 40-50
  • Known Autoimmune disease

Clinical Manifestations

  • History: fatigue, myalgias, pruritus, RUQ pain, amenorrhea
  • PE: jaundice, rash, spider angiomata, hepatomegaly, ascities, encephalopathy
  • Labs: prolonged PT, new coagulopathy
  • Onset is usually insidious
  • Up to 40% of individuals present with acute fulminant hepatitis w/ jaundice + new coagulopathy

Diagnosis

  • Liver biopsy is gold standard (mononuclear cell infiltrate & bridging necrosis on histologic examination
  • Elevated IgG, + ANA, +ASMA
  • Elevated AST/ALT AT LEAST 1.5x upper limit of normal

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Treatment

  • Indefinite treatment is liver transplant
  • Prednisone w or wo Azathioprine
  • Prednisone:
    • If patient is symptomatic w/ AST/ALT 10x upper limit
    • AST/ALT 5x upper limit of normal + 2x increase in serum globulins
    • Start 30mg then taper after 1 wk to 20mg, 15mg for 2-3 weeks and then maintain at 10mg
  • End points of treatment:
    • Remission, failure, incomplete response or drug toxcicity
    • Average duration of therapy is 1.5-2 years

Follow up & Considerations

  • CBC weekly x2 if Azathioprine therapy
  • Monitor for osteoporosis with prolonged steroid therapy
  • Repeat liver biopsy after 18 months to confirm histologic improvement to d/c steroids
  • Relapse rate is 60-80%

Complications

  • Primary Billiary Cirrhosis
  • Primary Sclerosing Cholangitis
  • Progression to Cirrhosis or Liver Failure
  • Varicies, encephalopathy, coagulopathies

2 thoughts on “Medical Musing of the Week: Autoimmune Hepatitis

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