The urinary tract is a relative common site of infection in infants and young children. Acute pyelonephritis (APN) is an important cause of acute morbidity and may result in long-term medical problems, including hypertension and reduced renal function. Accurate diagnosis is extremely important for two reasons: to permit identification, treatment, and evaluation of children who are at risk for kidney damage. Strategies of diagnosis and treatment depend on how ill the clinician assess the infant or young child to be. Antimicrobial therapy is warranted immediately. Imaging studies should be performed in all infants and young children with a documented initial urinary tract infection.

        Key words: infants, acute pyelonephritis, diagnosis, treatment, imaging studies