Autoimmune hepatitis

Chapter 5 Autoimmune hepatitis





Definition





TABLE 5.1 Autoimmune hepatitis: Basic diagnostic tests

































Diagnostic tests Clinical value
Serum AST and ALT, bilirubin, alkaline phosphatase, and γ-globulin levels Estimate severity of inflammatory activity; characterize pattern of liver injury
Serum albumin level and INR Estimate impairment of hepatic synthetic function
ANA, SMA, anti-LKM1, and AMA Document presence and nature of immune activity
Serum immunoglobulin levels Confirm mainly serum IgG elevation
Liver tissue examination Document that histologic changes support diagnosis
Exclude findings suggestive of other diagnoses
HBsAg, anti-HBc, IgM anti-HAV, and anti-HCV Document absence of concurrent viral infection
Ceruloplasmin level Exclude Wilson disease
Alpha-1 antitrypsin phenotype Exclude alpha-1 antitrypsin deficiency
Serum iron, transferrin, iron saturation and ferritin levels Exclude hereditary hemochromatosis

AMA, antimitochondrial antibodies; ANA, antinuclear antibodies; anti-HAV, antibody to hepatitis A virus; anti-HBc, antibody to hepatitis B core antigen; anti-HCV, antibody to hepatitis C virus; anti-LKM1, antibodies to liver kidney microsome type 1; AST, aspartate aminotransferase; ALT, alanine aminotransferase; HBsAg, hepatitis B surface antigen; IgG, immunoglobulin G; INR, international normalized ratio; SMA, smooth muscle antibodies.




Diagnosis





3. Interface hepatitis (Fig. 5.1) is required for the diagnosis, but lobular (panacinar) hepatitis (Fig. 5.2) in conjunction with interface hepatitis is within the histologic spectrum.








TABLE 5.2 International criteria for definite or probable diagnosis of autoimmune hepatitis



























Diagnostic features Definite diagnosis Probable diagnosis
Exclusion of risk factors for other diseases











Inflammatory indices



Autoantibodies ANA, SMA, or anti-LKM1 >1:80 in adults and >1:20 in children; no AMA ANA, SMA or anti-LKM1>1:40 in adults; other autoantibodies
Immunoglobulins Globulin, γ-globulin, or IgG level >1.5 times normal Hypergammaglobulinemia of any degree
Histologic findings




AMA, antimitochondrial antibodies; ANA, antinuclear antibodies; AT, antitrypsin; anti-LKM1, antibodies to liver kidney microsome type 1; AST, aspartate aminotransferase; ALT, alanine aminotransferase; IgG, immunoglobulin G; SMA, smooth muscle antibodies.






TABLE 5.4 Simplified international scoring system for the diagnosis of autoimmune hepatitis





























































Variable Result Points
Autoantibodies
ANA or SMA ≥1:40 +1
ANA or SMA ≥1:80 +2
anti-LKM1 ≥1:40 +2
anti-SLA Positive +2
Immunoglobulin level
Immunoglobulin G >ULN +1
  >1.1 ULN +2
Histologic findings
Morphologic features Compatible +1
  Typical +2
Viral disease markers
No viral hepatitis No viral markers +2
Pretreatment aggregate score:
Definite diagnosis   ≥7
Probable diagnosis   6

ANA, antinuclear antibodies; anti-LKM1, antibodies to liver kidney microsome type 1; anti-SLA, antibodies to soluble liver antigen; SMA, smooth muscle antibodies; ULN, upper limit of normal.



Pathogenesis



Principal hypotheses






Ancillary hypotheses







Subclassifications



Types






Variants





3. Autoimmune hepatitis and chronic viral hepatitis




Jun 4, 2016 | Posted by in GASTROENTEROLOGY | Comments Off on Autoimmune hepatitis
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