Autoimmune hepatitis (AIH) usually comes to attention through fatigue, and much of its clinical picture is built from non-specific complaints and laboratory clues rather than a single distinctive sign.
Symptoms and physical findings
More than 85% of patients mainly complain of easy fatiguability (fatigue). The physical examination is completely normal in about 25% of adults. When findings are present, the most common are hepatomegaly and splenomegaly, an enlarged liver and spleen. In 14-40% of patients there is a concurrent autoimmune-mediated disorder outside the liver, most often autoimmune thyroiditis or Graves disease.
Psychological features
Depression and anxiety are very common in these patients, especially after diagnosis, when they are driven by fear of progression. Physiological stress of any kind correlates with exacerbation of AIH, possibly because stress increases the production of pro-inflammatory cytokines, the signalling proteins that promote inflammation.
Laboratory findings
Liver tests and other routine changes
Because the examination is often unrevealing, the blood tests carry much of the picture. AST and ALT (the aspartate and alanine aminotransferases, enzymes released from damaged hepatocytes) and γ-globulin levels reflect the severity of the disease. Hyperbilirubinaemia, a raised bilirubin, is present in more than 80% of cases, usually within 3-fold above the upper limit of normal.
Alkaline phosphatase (ALP), an enzyme that rises in diseases of the bile ducts, is raised in more than 80% of cases, but in 67% it is only up to 2-fold above the upper limit of normal. An ALP elevation of more than 4-fold above that limit makes the diagnosis of AIH challenging, because it points toward a cholestatic disease, one in which bile flow is impaired, instead.
Hyperferritinaemia, with a high serum iron concentration, is also common, and serum vitamin D is low in 81% of patients. Failure to correct the vitamin D is a prognostic marker of treatment failure, with a high chance of cirrhosis.
Immunoglobulins
The laboratory hallmark of AIH is an increase in IgG with normal IgA and IgM — a selective rise in one immunoglobulin class (the antibody classes of the blood) rather than a general rise in all of them. A raised IgG does not show which antibodies are involved, so the autoantibodies that point at the liver are looked for next.