[Urinary tract infections in childhood. Old and new aspects].

Urinary tract infections are one of the most frequent infections during childhood. About 5% of all girls and 0.5% of all boys are suffering from at least one urinary tract infection until the end of schooltime. While the boys predominate in the first year of life with decreasing incidence of infection later on the girls remain predisposed up to an age of twelve. Each pediatrician faces every day the problem of a quick diagnosis and an appropriate therapy of urinary tract infections. While symptomless bacteriuria and cystourethritis do not destroy the renal parenchyma recurrent pyelonephritis may cause irreversible parenchyma scars up to a dialysis demanding renal failure. Besides the well-known mechanical risk factors (i.e. obstruction, reflux) functional risk factors like impaired bladder function alone as well as combined with mechanical ones are gaining in significance. Another factor predisponing to recurrent urinary tract infections is a local immunologic impairment of the urinary tract (i.e. P1-blood-group antigen, decreased urothelial function, increased urothelial colonisation). Age-appropriate and individual diagnosis and treatment are necessary first to avoid late damages and second to protect the children against unnecessary diagnostic and therapeutical managements.