The value of level diagnosis of childhood urinary tract infection in predicting renal injury.

252 infants and children were followed for 2 years after their first urinary tract infection. Each symptomatic infection was determined by simple laboratory examinations as upper pyelonephritic or lower urinary tract infection. I.v. urography was done at the beginning of the follow-up and 2 years later; micturating cystourethrography was taken after the third infection at the latest. Urological abnormalities were found in 26 patients (10%), and 12 subjects (5%) developed renal scars during the study. Patients, who had their first upper urinary tract infection before the age of 12 months, numbered 93, and 19 of them had urological abnormalities and 10 scars. Two renal scars occurred among the 71 subjects with their first pyelonephritic infection after the age of 12 months. No renal injury was detected in the 88 infants and children with lower symptomatic urinary tract infection or asymptomatic bacteriuria. The determination of the level of the infection may be a useful aid in detecting the harmful scar-forming urinary tract infections. Infants with a pyelonephritic infection are at high risk, and in need of an early urological evaluation.