Introduction: Urinary tract infections are the second most common type of bacterial infection in children. Atypical infections may be associated with a higher future risk of chronic kidney disease. The current range of diagnostic tests in children with a history of urinary tract infections is still a subject of discussions. Aim of the study: We attempted to determine the indications for renal scintigraphy and develop a nephrological care model for children aged ≤24 months based on the analysis of urinary tract infections in this group of patients. Materials and methods: We included 61 children aged ≤24 months [42 (68%) girls and 19 (32%) boys], hospitalised in the Department of Paediatrics, Paediatric Nephrology and Allergology, Military Institute of Medicine in Warsaw from 2008 to 2015 due to their first episode of urinary tract infection, in our retrospective analysis. Depending on the result of DMSA static renal scintigraphy performed 6 months after completed treatment of urinary tract infection, patients were classified into 3 groups: normal scintigraphy (group I), irregular tracer uptake indicating a suspicion of post-inflammatory renal pole lesions (group II), and signs of hypodysplasia (group III). The following variables were compared: age at first infection, gender, fever, inflammatory markers, aetiology, ultrasonographic findings, and the results of voiding cystourethrography for vesicoureteral reflux. Results: The median age at the time of first infection was 5.5 months in group I, 7 months in group II, and 7.5 months in group III. Febrile urinary infection was reported in 6/21 patients in group I, 4/19 patients in group II, and 6/21 patients in group III. Increased C-reactive protein was observed in 7/21 patients in group I, 6/19 patients in group II, and 6/21 patients in group III. Recurrent infections were reported for 5/21 children in group I, 8/19 in group II, and 12/21 children in group III. Atypical aetiology of urinary infection was reported for 3/21 patients in group I, 2/19 in group II, and 2/21 in group III. Abnormal ultrasonographic findings were observed in 4/21 patients in group I, 1/19 patients in group II, and 4/21 patients in group III. Vesicoureteral reflux in voiding cystourethrography was reported in 5/21 patients in group I, 8/19 patients in group II, and 10/21 patients in group III. The analysis of all the investigated parameters showed no statistically significant differences between the groups. Conclusions: Renal scintigraphy should be performed in the youngest children with a history of urinary tract infection as it was not possible to identify patients with post-inflammatory renal scarring secondary to urinary tract infection based on the course of infection, its aetiology, ultrasound findings and the presence of vesicoureteral reflux. Ultrasonography was not sensitive enough to diagnose renal hypodysplasia in our group of children.

thrombocytopaenia, cytomegaly, myelodysplastic syndrome, autoimmune lymphoproliferative syndrome