RESUMO
Elevated serum levels of transaminases must always be considered as an abnormal finding in children. Drugs and toxins must be eliminated first as possible hepatotoxic agents or co-factors. Antiviral hepatitis A immunoglobulin M serology is the first test to perform. However, others viruses with spontaneous benign courses are the most frequent cause. Only if initial presentation is severe or if liver tests remain abnormal after several weeks, other rare diseases can be sought. Aetiologies of persistent cytolysis associated to cholestasis are different in infancy and childhood. Metabolic, auto immune, genetic, muscular, endocrine disorders and obesity may cause isolated persistent hyper transaminasemia. Early diagnosis and management is essential, Isolated elevation of serum amino transferases in healthy looking children with negative investigations is mostly a benign condition that usually resolves within a year. Liver biopsy does not contribute much to diagnosis and is probably unnecessary