ARE YOUNGER CHILDREN AT HIGHEST RISK OF RENAL SEQUELAE AFTER PYELONEPHRITIS

Background The general belief about the relation between risk of renal sequelae after pyelonephritis and age is that infants are at highest risk and children older than 5 years at tower risk. This assumption ha s led to differences in treatment based on age. The aim of this prospe ctive study was to investigate the occurrence of renal lesions in chil dren aged 0-16 years. Methods Between May, 1994, and January, 1996, al l children aged 0-16 years who were admitted to our department with a diagnosis of probable pyelonephritis and a positive urine culture were included in this prospective study. All patients received antibiotics for 7-21 days. During the acute phase of urinary-tract infection, sci ntigraphy with technetium-99m-dimercaptosuccinic acid (DMSA) and ultra sonography were done. Voiding cystourethrography was undertaken at lea st 6 weeks after the end of antibiotic treatment. When scintigraphy sh owed renal parenchymal lesions, repeat scintigraphy was done after at least 2 months to assess the progression of renal lesions. For the ana lysis, children were grouped by age according to presumed risk of rena l sequelae after pyelonephritis: high risk (<1 year), moderate risk (1 -5 years), low risk (>5 years). Findings 201 patients were enrolled in the study (119 <1 year, 47 aged 1-5 years, 35 >5 years). During the a cute phase of urinary-tract infection, renal lesions were found in 66 (55%) infants under 1 year, in 37 (79%) children aged 1-5 years, and i n 24 (69%) children older than 5 years. Of these 127 children, 108 und erwent repeat scintigraphy after an average of 3 months (50 <1 year, 3 6 aged 1-5 years, 22 >5 years). Overall, renal scars were found on rep eat scintigraphy in 20 (40%) infants under 1 year, in 31 (86%) childre n aged 1-5 years, and in 14 (64%) children older than 5 years. 38 (36% ) of these 65 patients had vesicoureteric reflux. Among 88 children wh o had a first documented urinary-tract infection and underwent repeat scintigraphy, renal scars were found in 20 (43%) under 1 year, in 26 ( 84%) aged 1-5 years, and in eight (80%) older than 5 years. Interpreta tion This study did not confirm the conventional view that the risk of renal scars after pyelonephritis diminishes with age, We believe that ail children, irrespective of age, will benefit from any measure that prevents the development of renal sequelae.