Autoimmune hepatitis (AIH) is a progressive inflammatory liver disorder characterized by serologically elevated transaminase levels, increased levels of immunoglobulin G (IgG), and the presence of autoantibodies. AIH in childhood often presents acutely, and the incidence of cirrhosis at the time of diagnosis is higher in children than in adults. We report a case of AIH treated with methylprednisolone (mPSL) pulse therapy in a 15-year-old boy. The patient was referred to our hospital due to transaminitis without subjective symptoms. He did not have a family history of hepatitis or autoimmune disease, and was generally in good condition. Laboratory examinations revealed transaminitis and hyperphosphatasemia, and elevated levels of serum IgG. Tests for serum anti-nuclear antibody (ANA) and anti-smooth muscle antibody were both positive. Screens for viral hepatitis, drug-induced liver injury, and metabolic diseases such as Wilson disease were negative. Liver biopsy showed portal and periportal lymphocyte and interface hepatitis. There were no bile duct changes. Conventional treatment of AIH in childhood consists of prednisolone (1-2 mg/kg/day), and the remission rate is high. However, relapse during treatment is common. In response to relapse, the dosage is increased and the treatment period is extended, which can lead to the characteristic side effects of corticosteroids. Compared to conventional treatment of pediatric AIH, mPSL pulse therapy is reported not only to normalize aminotransferase in a shorter time span, but also to reduce the side effects of corticosteroids. In our patient, one course of mPSL pulse therapy was selected, because the patient and his family hoped for a shorter period of hospitalization. The patient was hospitalized for only 8 days, and his levels of serum aminotransferase, IgG, and ANA quickly improved. Apart from the already high rates of cirrhosis at diagnosis and relapse during treatment, AIH in childhood also often presents with complications of overlap syndrome, which can lead to a worse prognosis. It is important that both pediatricians and physicians cooperate during transitions of care.
