Thomson, Mary

ABSTRACT Drug-induced autoimmune-like hepatitis represents a distinct phenotype of drug-induced liver injury characterized by clinical, biochemical, and/or histological features resembling autoimmune hepatitis. We present a case of severe Isoniazid (INH) -induced drug-induced autoimmune-like hepatitis in a 62-year-old man with a dramatic response to corticosteroid therapy after INH discontinuation alone proved insufficient. Initial laboratory tests showed markedly elevated transaminases and profound hyperbilirubinemia. Despite INH discontinuation, his clinical condition did not improve. Liver biopsy revealed severe acute hepatitis with interface hepatitis, lymphoplasmacytic infiltration, and multiple foci of lobular confluent necrosis. Prednisone therapy led to rapid clinical improvement and normalization of liver biochemistries over 3 months.