The role of procalcitonin for acute pyelonephritis and subsequent renal scarring in infants and young children.

PURPOSE

We assessed the usefulness of procalcitonin as a biological marker in diagnosing acute pyelonephritis and for predicting subsequent renal scarring in young children with a first febrile urinary tract infection.

MATERIALS AND METHODS

Children 2 years old or younger with a first febrile urinary tract infection were prospectively studied. Renal parenchymal involvement was assessed by (99m)Tc-dimercaptosuccinic acid scan within 5 days of admission and after 6 months. Serum samples from all patients were tested for procalcitonin, C-reactive protein and white blood cell count measurements.

RESULTS

The 112 enrolled patients (age range 24 days to 24 months old) were divided into acute pyelonephritis (76) and lower urinary tract infection (36) groups according to the results of (99m)Tc-dimercaptosuccinic acid scans. Median values of procalcitonin, C-reactive protein and white blood cell count at hospitalization were significantly higher in patients with acute pyelonephritis than in those with lower urinary tract infection. The area under receiver operating characteristic curves showed that procalcitonin was superior to C-reactive protein and white blood cell count as a marker for diagnosing acute pyelonephritis. Initial and post-antibiotic treatment procalcitonin values were significantly higher in children with renal scarring than in those without scarring (p <0.001). Procalcitonin values at hospitalization and after treatment were independent predictors of later renal scarring on logistic regression analysis.

CONCLUSIONS

Our results indicate the superior diagnostic accuracy of procalcitonin for predicting acute pyelonephritis in children 2 years old or younger. Higher initial and posttreatment procalcitonin values are independent risk factors for later renal scarring.