Uncovering the Mask: A Rare Presentation of Autoimmune Hepatitis Type 2 in a 54 Year-Old Man

Abstract

Autoimmune Hepatitis (AIH) is a chronic liver disorder that is found in both adult and pediatric patients characterized by abnormal aminotranferase levels, detectable autoantibodies and elevated immunoglobulin G (IgG) with significant inflammation on liver histology with presence of plasma cells. There are two types of AIH are identified by specific serological markers. Type 1 is associated with detectable ANA and/or smooth muscle antibody (ASMA) and can be found in both adults and children. Type 2 is associated with anti-liver-kidney-microsome (anti-LKM) type 1 and/or liver cytosol type 1 and is primarily a pediatric or young adult illness. We describe an unusual case of AIH type 2 in a 54-year-old African American male, previously in good health, who presented with cyclical fevers (max of 1020) and diffuse joint pains. He worked in a rural hospital in Ghana four months prior, but had no known exposures, and had been taking malarone for prophylaxis. He regularly used whey protein powder, but denied other meds. Within one week, his AST level was 639 U/L, ALT was 972 U/L with alkaline phosphatase level of 362 U/L. Comprehensive work up for infectious causes including malaria, Babesia, EBV, Ehrlichia, CMV, and viral hepatitides were negative. His IgG level rose to 2227 mg/dl, while ANA and ASMA were undetectable. Liver biopsy was remarkable for interface hepatitis with extensive inflammation extending into the lobules and portal tracts with marked lymphocytes, plasma cells and eosinophilia. Anti-LKM was requested, but results were not available. All of these features together were consistent with a rare presentation of type 2 AIH. He was started on prednisone 30mg daily for 2 weeks then 20mg daily for 2 weeks with azathioprine 50mg daily which reduced his aminotransferases almost immediately. He was transitioned to 10mg of prednisone and 50mg azathioprine daily for maintenance after liver associated enzyme labs normalized. Despite the clinical presentation of this patient being concerning for an infectious or a drug-induced cause, it was the liver biopsy that sealed the diagnosis of AIH. Liver biopsy in AIH classically shows portal and periportal lymphocyte and plasma cell infiltrates that disrupt the parenchymal limiting plate, causing interface hepatitis. Our patient emphasizes the role of liver biopsy in patients with elevated liver enzymes for whom no identifiable etiology has been found.