Summary
Autoimmune hepatitis (AIH) is a rare form of chronic hepatitis that predominantly affects women. Although the etiology is unclear, it is commonly associated with other autoimmune conditions (e.g., type 1 diabetes mellitus, celiac disease). Clinical presentation varies and patients may be asymptomatic or even show signs of acute liver failure. Diagnosis is established based on the detection of autoantibodies (especially anti-smooth muscle antibodies) and the histologic findings of liver biopsy. Treatment consists of immunosuppressive medications such as prednisone and azathioprine. The prognosis is favorable if patients are treated appropriately; without treatment, cirrhosis may develop.
Epidemiology
- Prevalence: 0.1–2/100,000 white adults in the US, even less so in other ethniticities [1]
- Bimodal distribution: 10–20 years and 40–60 years [2]
- Sex: ♀ > ♂ (∼ 4:1) [3]
Epidemiological data refers to the US, unless otherwise specified.
Etiology
- Idiopathic
- AIH is commonly associated with other autoimmune conditions (e.g., type 1 diabetes mellitus, Hashimoto thyroiditis, celiac disease).
References:[4]
Clinical features
AIH has an insidious onset in most patients and its presentation varies widely, ranging from asymptomatic disease to severe symptoms or even acute liver failure.
-
Nonspecific symptoms
- Fatigue
- Abdominal pain
- Weight loss
- Signs of acute liver failure (∼ ⅓ of patients)
Diagnostics
-
Laboratory tests
- ↑ ALT and ↑ AST
- Normochromic anemia, thrombocytopenia, mild leukopenia, ↑ erythrocyte sedimentation rate (ESR)
- Autoantibodies: antinuclear antibodies (ANA) and anti-smooth muscle antibodies (ASMA); less commonly anti-liver-kidney microsome-1 antibody or anti-soluble liver antigen antibody
- Hypergammaglobulinemia (↑ IgG)
- Liver biopsy: Biopsy should be performed following the detection of AIH antibodies to confirm the diagnosis.
Diagnosis is established based on positive autoantibodies (e.g., anti-smooth muscle antibodies) and histological findings suggestive of autoimmune hepatitis!
References:[4][5]
Differential diagnoses
- Viral hepatitis (e.g., hepatitis C)
- Primary sclerosing cholangitis
- Primary biliary cirrhosis
- Alcohol-related hepatoxicity
The differential diagnoses listed here are not exhaustive.
Treatment
-
Immunosuppressive medications
- Initial therapy: combination of prednisone and azathioprine
- Maintenance therapy: azathioprine or prednisolone
-
Liver cirrhosis
- See “Treatment of cirrhosis.”
- Liver transplantation is indicated in cases of decompensated liver cirrhosis.
Prognosis
-
10-year survival rate with treatment: > 90% [6]
- Lifelong therapy is usually required.
- Increased risk of developing hepatocellular carcinoma (HCC): follow-ups are recommended
- Increased risk of liver cirrhosis if left untreated