Aim We aimed to investigate in children with a history of acute pyelonephritis the influence of unilateral post-pyelonephritic renal scarring detected by DMSA scan on serum (S-CysC) and urine cystatin C (U-CysC) as well as upon other traditional markers of renal damage.

Methods Children with DMSA proven pyelonephritis (n = 28) were grouped as either scar [+] (n = 19, unilateral renal scarring) or scar [-] (no scarring, n = 9). The scar [+] group was further divided into scar-1 (differential DMSA uptake, Delta(DMSA) > 10%; n = 8) and scar-2 (Delta(DMSA) > 10%, n = 11) subgroups. S-CysC, serum creatinine, urine NAG, microalbumin, protein, fractional sodium excretion (FENa), tubular phosphate reabsorption (TPR), and U-CysC/Cr were evaluated in all patients.

Results Neither S-CysC nor U-CysC were affected by age, height, and weight. scar [+] versus scar [-] groups and scar-1 versus scar-2 subgroups were not different with regard to all studied parameters. S-CysC did not increase in children with post-pyelonephritic unilateral renal scarring. However, 11 children with slightly increased (> 0.95 mg/l) S-CysC levels in scar [+] group tended to have higher Delta(DMSA), albeit not significantly. Furthermore, U-CysC/Cr correlated well with urine microalbumin, NAG, and FENa in all children and the scar [+] group (P < 0.05).

Conclusions S-CysC and U-CysC did not differ among pediatric patients with and without unilateral post-pyelonephritic renal scarring. However, Delta(DMSA) uptake between the two kidneys tended to be raised in children with S-CysC levels higher than the reference ranges. Additionally, U-CysC/Cr exhibits parallelism with tubular functions.