Anna Maria Wasilewska

Introduction and objective: Urinary tract infections can recur in children, and due to their potential long-term consequences, they require appropriate diagnosis and prompt treatment. Although Escherichia coli is the most common aetiology, an increase in infections with drug-resistant strains has been observed. The aim of this study was to develop current diagnostic and treatment recommendations in the era of increasing microbial resistance. Materials and methods: The recommendations are based on updated guidelines developed by the experts of the Polish Society of Paediatric Nephrology and a literature review. Results: Because the symptoms of urinary tract infection are often non-specific, urinalysis and urine culture should be performed in children presenting with fever without an identifiable cause. Correct method of urine collection and interpretation of the results are crucial for therapeutic decisions. Treatment should be continued for 7–14 days for upper and 3–5 days for lower urinary tract infections; the choice of the narrowest-spectrum antimicrobial should be based on bacterial susceptibility. Antibiotic prophylaxis is limited and recommended in children with grade III–V vesicoureteral reflux. Non-pharmacological management should include treatment of bladder and bowel dysfunction. Ultrasound is recommended for all children up to 24 months of age. Indications for voiding cystourethrography are limited to cases with ultrasound abnormalities, recurrent and septic infections. Conclusion: The paper provides up-to-date, practical recommendations for the diagnosis and management of urinary tract infections in children in the era of increasing microbial resistance and restricted indications for invasive radiological investigations.

Background: Although steroid therapy is a standard of care for nephrotic syndrome treatment, 15–20% of patients do not respond to it. Finding the genetic background is possible in >10% of steroid-resistant nephrotic syndrome (SRNS) cases. Variants in genes encoding nuclear pore complex proteins are a novel cause of paediatric steroid-resistant nephrotic syndrome (SRNS). Recent studies suggest NUP93 variants to be a significant cause of paediatric onset SRNS. The clinical data on certain variants and disease history are still very limited. Methods and results: We report the SRNS case of a 12-year-old boy with two detected NUP93 variants, which are pathogenic and possibly pathogenic. The onset of the disease was early and severe. The patient was admitted to the paediatric nephrology department due to nephrotic-range proteinuria and hypoalbuminemia with a long medical history of steroid and non-steroid immunosuppressive treatment. The genetic panel targeting 50 genes, clinically relevant for nephrotic syndrome, was performed. The only gene which was found to be affected by mutations, namely c.2326C>T and c.1162C>T, respectively, was NUP93. Conclusions: NUP93 variants are rarely identified as causes of SRNS. Clinical data are of utmost importance to establish the standard of care for SRNS patients suffering from this genetic disfunction. This is the first case of a heterozygous patient with the c.2326C>T and c.1162C>T variants and confirmed clinical history of the SRNS described so far. Our data suggest the clinical relevance of the c.1162C>T variant.