Snapshot A 24-year-old woman with a past medical history of vitiligo presents to the emergency room for abdominal pain. She has had abdominal pain intermittently for the past few weeks and has seen her primary care physician for this issue. On exam, she is slightly jaundiced with scleral icterus and has hepatosplenomegaly. Viral serologies are negative. Labs are significant for elevated transaminitis and positive smooth muscle antibody. She is started on prednisone. Introduction Clinical definition autoimmune chronic inflammation of the liver type 1 AIH (autoimmune hepatitis) most common + antinuclear antibodies (ANA) + smooth muscle antibodies (SMA) type 2 AIH + liver/kidney microsome type 1 antibody (antiLKM1) + antimitochondrial antibody (AMA) Associated conditions other autoimmune diseases thyroid disease ulcerative colitis celiac disease Epidemiology Demographics female > male type 1 AIH young adults type 2 AIH children Risk factors viral hepatitis measles medications may trigger a relapse Genetics AIRE gene mutation ETIOLOGY Pathogenesis T-cell mediated autoimmune disease Presentation Symptoms and physical exam jaundice abdominal pain encephalopathy pruritus hepatomegaly splenomegaly ascites Studies Diagnostic testing diagnostic approach diagnostic testing must rule out viral hepatitis studies serum antibodies type 1 AIH ANA SMA type 2 AIH antiLKM1 AMA liver function tests ↑ transaminases ↑ alkaline phosphatase serum protein electrophoresis (SPEP) hypergammaglobulinemia liver biopsy most accurate test bridging or multilobular necrosis, inflammation, and fibrotic changes may show cirrhosis Differential Viral hepatitis distinguishing factor positive serologies for hepatitis viruses Hemochromatosis distinguishing factor also presents with restrictive cardiomyopathy, darkening skin, joint pain, and pancreatic insufficiency Treatment First-line steroids indication transaminitis > 10x normal histology showing bridging necrosis or multilobular necrosis azathioprine indication often used alongside steroids Second line other immunosuppressants drugs mycophenolate cyclosporine tacrolimus liver transplant indication disease refractory to medical therapy Complications Cirrhosis Hepatocellular carcinoma Prognosis Relapse is common