Autoimmune Hepatitis Diagnosis and Management

Diagnostic Criteria

The American Association for the Study of Liver Diseases recommends that a diagnosis of autoimmune hepatitis (AIH) be made based on a combination of clinical, laboratory, and histological findings, including positive antinuclear antibodies (ANA) and smooth muscle antibodies (SMA), which are present in up to 80% of patients 4
Elevated liver function tests (LFTs) and beta globulin are characteristic features of AIH, reflecting hypergammaglobulinemia 1, 2
The International Autoimmune Hepatitis Group (IAIHG) scoring system can be used to diagnose AIH, with a score of 15 or higher indicating "definite" AIH and a score of 10-14 indicating "probable" AIH 1, 5

A complete autoantibody panel should be performed to confirm the diagnosis of AIH, including ANA, SMA, and anti-soluble liver antigen (anti-SLA) 1, 4, 5
Immunoglobulin levels, including IgG, should be measured to support the diagnosis of AIH 1, 5
A liver biopsy is essential for the diagnosis of AIH, with interface hepatitis being a hallmark finding 2, 3

The American Association for the Study of Liver Diseases recommends that standard induction therapy be initiated promptly for patients with moderate to severe AIH manifestations, including prednisone 15-20 mg/day and azathioprine 1-2 mg/kg/day 1, 3
Treatment goals include normalization of transaminases and IgG levels, resolution of symptoms, and histological improvement with reduction of inflammation 1, 2, 3, 5

Untreated AIH can lead to cirrhosis in at least 40% of survivors and esophageal varices in 54% within 2 years after cirrhosis 2
With treatment, approximately 80% of patients can achieve remission, and long-term survival approaches that of the general population 5
Regular screening for hepatocellular carcinoma and surveillance for esophageal varices are recommended for patients with cirrhosis 2, 5

Acute presentation of AIH can occur in 25% of cases, sometimes with normal IgG and negative autoantibodies initially 6
Seronegative AIH can occur in some patients, with clinical and histological features of AIH without classic autoantibodies 7
Overlap syndromes with primary biliary cholangitis (PBC) or primary sclerosing cholangitis (PSC) should be considered if cholestatic features are present 5