Purpose: Acute urinary tract infection (UTI) is one of the most common bacterial infections in children and a major cause of antibiotic use. Increasing antimicrobial resistance has raised concerns regarding the appropriate selection of empirical antibiotics in pediatric UTIs.Methods: We retrospectively analyzed 571 children diagnosed with culture-confirmed acute UTI at a single tertiary center between 2015 and 2020 and compared the findings with data from a previous study conducted at the same institution between 2003 and 2008. Uropathogen distribution, antibiotic susceptibility patterns, extended-spectrum β-lactamase (ESBL) prevalence, and imaging findings were evaluated.Results: Gram-negative organisms accounted for 98.2% of UTIs, with Escherichia coli being the most common pathogen (89.1%). Compared with 2003–2008, antibiotic susceptibility significantly decreased during 2015–2020 for several commonly used agents in both the overall bacterial population and E. coli isolates. The prevalence of ESBL-producing organisms increased markedly. No significant association was observed between microbiological findings and imaging abnormalities.Conclusions: Antibiotic resistance in pediatric UTIs increased significantly over an approximately 10-year period within the same institutional setting. These findings highlight evolving antimicrobial resistance and underscore the importance of continuous local surveillance to guide empirical antibiotic selection.
Purpose: This study aimed to evaluate the efficacy and safety of a nafamostat mesilate (NM) protocol in pediatric patients undergoing continuous renal replacement therapy (CRRT).Methods: A retrospective review was performed in 107 patients who underwent at least 24 hours of CRRT between January 2018 and December 2022 at Samsung Medical Center. According to the anticoagulation strategy used during CRRT, patients were categorized into three groups: no anticoagulation (Group 1), NM (Group 2), and heparin (Group 3).Results: A total of 107 patients (mean age 7.8±5.5 years) were included. The mean duration of CRRT was 11.7 days, and the overall survival rate was 61.7%. NM and heparin were administered to 38 and 27 patients, respectively, whereas 42 patients received no anticoagulant therapy. Mean filter life did not differ significantly among the groups (no anticoagulation 32.1 hours vs. NM 26.7 hours vs. heparin 33.9 hours; P=0.092). However, among 11 patients in the NM group who initiated NM during ongoing CRRT because of inadequate filter lifespan without anticoagulation, hemofilter lifespan significantly increased from 19.8±7.7 to 27.0±9.4 hours after NM initiation (P=0.030). No known complications associated with NM use were observed. One patient experienced minor bleeding at the peritoneal dialysis catheter site during heparin administration. Survival rates did not differ significantly among the groups.Conclusions: NM appears to be a safe anticoagulation option in pediatric CRRT patients at high bleeding risk. While overall filter life was comparable across groups, NM significantly prolonged hemofilter lifespan in patients switched from no anticoagulation, supporting its potential role as a rescue strategy.
Minimal change disease (MCD) is the leading cause of idiopathic nephrotic syndrome in children, accounting for >85% of cases in those aged 1–12 years. Although 80%–90% of patients achieve initial remission with glucocorticoids, steroid dependence or frequent relapses occur in 55%–60% of cases, necessitating prolonged immunosuppression. Long-term steroid exposure in children is associated with severe age-specific adverse events, including growth retardation, skeletal dysplasia, cataracts, and impaired vaccine responses from immunosuppression. Steroid resistance and chronic kidney disease may also develop in some patients. Recent clinical evidence and literature (2015–2025) have transformed our understanding of MCD from the traditional “single T cell-driven” hypothesis to a multidimensional interactive regulatory network. This network is based on coordinated Tand B-cell dysregulation, mediated by defined podocyte injury pathways and modulated by genetic and environmental factors. Distinct pediatric traits stem from immature immune system development and pediatric podocyte plasticity. In this review, we synthesize recent advances in these pediatric pathogenic mechanisms, delineate age-dependent differences between childhood and adult MCD, and propose a precision medicine framework for disease subtyping, noninvasive biomarker development, and targeted therapies. This work addresses critical unmet clinical needs in the long-term management of pediatric MCD.
Pediatric kidney diseases encompass a diverse group of disorders, ranging from congenital anomalies to glomerulopathies. Unlike adults, where lifestyle factors predominate, approximately 30% of pediatric cases constitute inherited kidney diseases. This high heritability underscores the critical importance of early and accurate genetic testing. While targeted gene panels have historically been the first-line diagnostic tool, they are limited by fixed gene content and an inability to detect complex structural variants. Next-generation sequencing, specifically exome sequencing and genome sequencing, has transformed the diagnostic landscape by enabling an unbiased, simultaneous analysis of all disease-associated genes. These modalities enhance diagnostic yields by identifying structural variants including copy number variants and non-coding variants often missed by conventional panels. Furthermore, they allow for the discovery of novel disease genes through periodic reanalysis. Despite these advancements, a significant diagnostic gap persists due to the limitations of short-read sequencing in complex genomic regions and the difficulty of interpreting variants of uncertain significance. To address these challenges, integrating long-read sequencing to resolve complex genomic regions and implementing systematic reanalysis protocols are recommended. This review provides a comprehensive comparison of diagnostic yields across testing modalities and discusses the future of genomic profiling in pediatric kidney diseases.
Branchio-oto-renal (BOR) syndrome is a rare autosomal dominant disorder caused by pathogenic variants in EYA1, SIX1, or SIX5, which affect the branchial arches, auditory system, and kidneys. Diagnosis integrates clinical criteria that require major criteria such as branchial anomalies, hearing loss, or preauricular pits, as supported by genetic testing. Gene-targeted testing confirms typical BOR syndrome phenotypes, whereas comprehensive genomic testing identifies atypical cases. Management is tailored to the individual phenotypes. Kidney anomalies, the most important prognostic factor, necessitate early nephrology referral and interventions such as pyeloplasty for ureteropelvic junction obstruction or kidney replacement therapy for kidney failure. Hearing loss is addressed using hearing aids, surgical correction, or cochlear implantation, depending on the type and severity of hearing loss. Branchial anomalies, including cysts and sinuses, can be managed conservatively or surgically when symptomatic. Genetic counseling plays a critical role, given the 50% inheritance risk and the implications for family planning. Prenatal ultrasonography is recommended for detecting renal anomalies during at-risk pregnancies. Management of BOR syndrome requires a multidisciplinary approach that integrates otolaryngology, nephrology, and genetics. Advances in genomic technologies and a deeper understanding of phenotypic variability are essential for improving the outcomes of patients with BOR.
This case report describes a newborn diagnosed with very-early-onset autosomal dominant polycystic kidney disease (VEO-ADPKD) and congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. The patient presented with prenatally detected kidney cysts and exhibited clinical and laboratory features consistent with salt-wasting, including markedly elevated 17-hydroxyprogesterone levels, requiring treatment with hydrocortisone, fludrocortisone, and sodium chloride. Genetic analysis revealed a de novo truncating variant in PKD1 and two variants in CYP21A2. Hypertension developed at 3 years and 7 months despite unchanged steroid replacement doses, requiring antihypertensive treatment, and resolved after mineralocorticoid dose reduction. This case highlights the competing therapeutic demands of concurrent salt-wasting CAH and VEO-ADPKD, underscoring the importance of early genetic evaluation and integrated multidisciplinary surveillance.
The kidney plays an important role in normal linear growth throughout childhood by regulating systemic insulin-like growth factor-1 (IGF-1) bioavailability through the filtration and processing of IGF-binding proteins and by serving as a target organ for growth hormone (GH). In pediatric chronic kidney disease (CKD), impaired renal function is associated with reduced availability of bioactive IGF-1 despite normal or modestly elevated total IGF-1 concentrations, reflecting altered binding protein dynamics and functional GH–IGF resistance. These changes are frequently accompanied by impaired growth velocity and reduced height, particularly in advanced CKD stages. This review synthesizes experimental and observational evidence examining the role of the kidney and IGF-1 axis in physiological linear growth and CKD-related growth failure. Observational studies demonstrate consistent associations between renal volume, IGF-1 parameters, and height outcomes. Across CKD stages, progressive reductions in free IGF-1 parallel worsening renal function and growth impairment. Recombinant human GH therapy improves growth velocity and may help children achieve near-adult height closer to their genetic potential when initiated early and appropriately monitored. Collectively, these findings support a renal–endocrine model of pediatric growth regulation in health and disease.
Purpose This study aimed to investigate the long-term clinical course of unilateral multicystic dysplastic kidney (MCDK) and the contralateral kidney in Korean children. Methods We retrospectively reviewed the medical records of 71 pediatric patients diagnosed with unilateral MCDK who were followed for more than 12 months between January 2005 and December 2024. Results Of the 71 patients, unilateral MCDK was located on the left side in 39 cases (54.9%). The mean age at diagnosis was 1.1 months, and the mean follow-up duration was 7.3 years. Sixty-three patients (88.7%) were diagnosed with MCDK by prenatal ultrasonography. The mean length of MCDK measured by ultrasonography in patients diagnosed within the first 3 months of life was 4.2±1.7 cm. Sixty-six patients (93%) demonstrated complete or partial involution of MCDK by 2 years of age, while five patients who did not show regression by that age underwent nephrectomy. Compensatory hypertrophy (>2 standard deviation) of the contralateral kidney was common in neonates, declined to its lowest point at 3 to 4 years of age, and subsequently increased through adolescence, reaching 81.8% by 9 to 10 years of age. No significant difference in estimated glomerular filtration rate was observed between patients with and without compensatory hypertrophy. Conclusions If complete or partial involution of unilateral MCDK in Korean children is confirmed by age 2, most lesions resolve spontaneously. Compensatory hypertrophy of the contralateral kidney increases progressively from birth, reaching approximately 80% of patients by age 10 years.
Purpose Renal anomalies account for 50% to 80% of vertebral, anal, cardiac, tracheoesophageal fistula with or without atresia, renal and limb (VACTERL) associations. Some of these patients develop chronic kidney disease (CKD). This study evaluated the clinical characteristics, prevalence, and risk factors of CKD in VACTERL-association patients. Methods The medical records of pediatric VACTERL-association patients who visited Samsung Medical Center from January 2011 to December 2019 were reviewed retrospectively using a traditional Schwarz formula to estimated glomerular filtration rate by serum creatinine. Cases of CKD were classified according to Kidney Disease Improving Global Outcomes guidelines as stages 2 to 5. Results A total of 47 VACTERL-association patients were enrolled. Renal anomalies were presented in 89.4% of patients. The mean follow-up period was 3.26 years. Half of the patients had a urinary tract infection, and 83.3% of these experienced more than one. Vesicoureteral reflux was detected in 23 patients. Twenty patients experienced acute kidney injury (AKI). Among them, 20% progressed to CKD. Two AKI patients required kidney replacement therapy. In this study, the prevalence of CKD was 14.9%. Complex renal anomalies and stage 3 AKI increased the risk of CKD progression in patients with VACTERL association by 11-fold and 9-fold, respectively (P=0.020 and P=0.041). Conclusions Several factors such as complex renal anomalies and stage 3 AKI may influence kidney function in VACTERL association. A further longitudinal study of CKD in VACTERL-association patients is required.
Congenital antithrombin III (ATIII) deficiency is a rare hereditary thrombophilia that is caused by SERPINC1 variants. Reports on KILT syndrome, which is defined by the triad of kidney anomaly, inferior vena cava (IVC) anomaly, and leg thrombosis, have been sporadic. We described the case of a 10-year-old boy with a solitary left kidney and IVC agenesis who carried compound heterozygous variants in SERPINC1. He presented with flank pain due to renal infarction and subsequently developed massive perirenal effusion. Despite anticoagulation and prolonged percutaneous drainage, the effusion persisted and was confirmed to be of lymphatic origin. Imaging revealed abnormal lymphatic flow related to venous hypertension in the renal hilum. Complete resolution of the effusion was achieved following four sessions of ethanol sclerotherapy. To the best of our knowledge, this was the first reported case of ATIII deficiency complicated by refractory perirenal lymphatic leakage. The case suggested a potential link between thrombosis and secondary lymphatic dysfunction and demonstrated the effectiveness of repeated sclerotherapy for refractory perirenal effusion. Early recognition of hypercoagulable states in children with IVC and renal anomalies is crucial for the prevention of thromboembolic events.
Tubulointerstitial damage is a common diabetic kidney disease (DKD) complication caused by diabetes mellitus. However, many patients may not present with albuminuria or impaired glomerular filtration rate (GFR), making it difficult to detect kidney dysfunction. Kidney injury molecule-1 (KIM-1) is an emerging biomarker of early DKD, reflecting tubular injury before glomerular dysfunction. We explored the association between KIM-1 and DKD in children and adolescents with type 1 diabetes (T1D). We included 10 studies with 842 participants published between 2016 and 2025. A literature search of MEDLINE/PubMed, Cochrane Library, and Scopus was conducted from inception through January 5, 2026. The mean difference with a 95% confidence interval (CI) was calculated, and a P-value of <0.05 was considered statistically significant. A quality assessment of the included studies was conducted using the Newcastle-Ottawa Scale. In the meta-analysis of four studies, the urinary KIM-1 (uKIM-1)/creatinine ratio was elevated before changes in estimated GFR (95% CI, 0.02–0.48; P=0.03). This review suggests that uKIM-1/creatinine ratio and uKIM-1 may act as promising tubular biomarkers associated with early kidney injury in pediatric patients with T1D. However, further data are needed to clarify their role in pediatric DKD.
Purpose Idiopathic nephrotic syndrome (NS) often necessitates prolonged or repeated corticosteroid treatment, which increases the risk for steroid-induced posterior subcapsular cataract (SI-PSC). Previous research on its burden remains limited. Here, we aimed to determine the prevalence and predictive risk factors of SI-PSC in children with NS. Methods This cross-sectional study was conducted in the Pediatric Nephrology Department of The Kidney Centre, Karachi, Pakistan, from October 2023 to October 2025. The study included 150 children with NS, aged 2–16 years, who had received oral prednisolone for more than 6 months. Demographic and clinical information were collected through caregiver interviews and medical record review. All participants underwent a detailed slit-lamp examination by the same ophthalmologist. Associations between cataract formation and demographic or treatment-related variables were analyzed statistically. A P-value of ≤0.05 was considered significant. Results Cataracts were detected in 23 children (15.3%). Most patients had early lenticular changes, but only two required surgical intervention. Other ocular abnormalities were uncommon (4.7%). Cataracts occurred more frequently in males and in children younger than 10 years. Cumulative corticosteroid doses were nearly identical in patients with and without cataracts. Children with frequently relapsing NS accounted for the highest proportion of those with SI-PSC. Systemic hypertension was the adverse effect most strongly associated with cataract development. Conclusions SI-PSC is a notable complication in children receiving long-term corticosteroid therapy. Our findings underscore the importance of routine ophthalmologic screening. Individual susceptibility, including potential genetic factors, might play a role in cataract development and warrant further investigation.
Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary renal disorder and primarily arises from mutations in either the polycystic kidney disease 1 (PKD1) or 2 (PKD2) gene. Although traditionally categorized as an adult-onset disease, cystogenesis often begins in utero, and structural changes may become evident during childhood. Although most pediatric patients with ADPKD remain asymptomatic, hypertension occurs in 20%–40% of cases, and albuminuria may also be present. Both findings represent early, treatable manifestations that can significantly influence long-term prognosis. Ultrasonography is the preferred diagnostic modality; however, genetic testing is indicated in very-early-onset or atypical cases. The cornerstone of disease management is rigorous blood pressure control using renin–angiotensin system inhibitors, along with lifestyle modifications such as sodium restriction and adequate hydration. Early diagnosis and intervention are essential for optimizing long-term clinical outcomes in pediatric patients with ADPKD. This study aimed to provide a comprehensive review of the genetics, pathophysiology, clinical manifestations, diagnosis, treatment, and future management of pediatric ADPKD.
Since the completion of the Human Genome Project, genome-based medicine has progressed from a predominantly research-driven endeavor to a field of increasing clinical relevance. In Korea, the Korea National Institute of Health (KNIH) has played a central role in the establishment of the necessary research infrastructure that supports the secure and responsible use of genomic and clinical data. These efforts have enabled the generation of comprehensive genomic datasets representative of the Korean population and, together with the Korea Biobank Array optimized for population-specific variants, have strengthened discovery-driven research and accelerated advances in disease gene identification and risk prediction. More recently, KNIH has expanded analyses based on whole-genome sequencing data to support clinical translation, enabling more comprehensive variant detection and facilitating the application of genomic information to disease diagnosis and precision medicine research. These national genomic resources provide an important foundation for improving the diagnosis and management of genetically mediated conditions, including pediatric kidney diseases, where early etiologic diagnosis can substantially influence clinical decision-making and long-term outcomes. Further strengthening of institutional and regulatory frameworks will be essential to support routine clinical implementation and maximize the public health impact of genomics in Korea.
Urinary tract infections (UTIs) are among the most common bacterial infections in infants and a significant cause of antibiotic exposure. Recent advances in culture-independent sequencing and improved urine culture techniques have revealed that urine contains resident microbial communities, collectively known as the urinary microbiome (urobiome). Additionally, emerging evidence supports the existence of a gut-bladder axis, where intestinal dysbiosis may lead to uropathogen colonization, immune modulation, and UTI recurrence. This review summarizes current pediatric research connecting alterations in the urinary and gut microbiomes to UTI susceptibility, recurrence, and clinical outcomes, specifically in infants. We also address the unique methodological challenges in pediatric urobiome research and outline future directions for applying microbiome and metabolomics insights to clinical practice.
Cystinosis is a rare autosomal recessive lysosomal storage disorder with an incidence of approximately 1 in 100,000 to 200,000 live births. It is the most common cause of inherited pediatric Fanconi syndrome (FS). Here, we describe the cases of two infants from unrelated families who presented with polyuria and features of proximal renal tubular dysfunction. Although no corneal cystine deposition was observed at presentation, clinical suspicion and genetic analysis confirmed the diagnosis of nephropathic cystinosis. Both patients carried the same pathogenic variant in the CTNS gene, suggesting that it is a hotspot in this region. These patients were managed with oral cysteamine therapy, cysteamine eye drops, and supportive therapy for FS and are currently doing well. Genetic diagnosis plays a crucial role in the early detection of cystinosis, facilitating timely initiation of cysteamine therapy, and should be considered in infants with FS.
Anti-glomerular basement membrane disease (anti-GBMD) is a rare small-vessel vasculitis presenting as rapidly progressive glomerulonephritis and/or diffuse alveolar hemorrhage. A third of patients with anti-GBMD have antineutrophil cytoplasmic antibodies and are known as double-positive patients. There are a limited number of pediatric double-positive cases published in the literature. In this case report, we summarize the presentation, treatment, and outcome of a patient with anti-GBMD with both anti-myeloperoxidase and anti-GBM antibodies, highlighting the safe use of rituximab. We also describe atypical complications in our case, including significant weight loss of unclear etiology and development of recurrent episodes of acute pericalcific arthritis.
