Urinary tract infection in infants and children: an update with special regard to the changing role of reflux.

The aim of this study was to present current theories of pathogenesis and prognosis in urinary tract infection (UTI) and renal scarring during infancy and childhood, with special regard to new insights concerning the role of vesico-ureteral reflux (VUR). For a long time VUR and UTI were considered the only risk factors for renal scarring in childhood. Now a wider spectrum of contributing conditions is commonly accepted, which all may pose different clinical consequences and require different imaging approaches. Particularly bilateral renal scarring causes long-term sequalae; therefore, renal involvement in UTI with potential scarring has become the clinical and imaging focus, and proper diagnosis of UTI as the key factor for further management has become even more important. The VUR still remains one issue on a list of important factors such as treatment onset and response, bacterial virulence, immunological factors, genetic disposition, anatomical variants, and lower urinary tract dysfunction. Recent advances in knowledge leading to changed patho-physiological concepts, and new imaging techniques, may consecutively impact the presently established standard imaging algorithms. New, advanced imaging techniques offer improved and accelerated comprehensive imaging of the paediatric urinary tract. At present, this is complimentary to the established gold standard techniques. Strong research efforts have to be made before suggesting significant changes of current imaging concepts; however, based on recent technical advances and new insight on the natural history of paediatric urological diseases, potential changes of established imaging algorithms need to be discussed and evaluated.