Vesico-ureteral reflux diagnosis after initial kidney abscess: Results from a Paediatric Tertiary Hospital.

AIMS: Guidelines regarding voiding cystourethrogram (VCUG) indications following a paediatric kidney abscess are lacking. This study evaluates vesicoureteral reflux (VUR) prevalence and outcome after a first kidney abscess. METHODS: This retrospective study included all children presenting to a tertiary paediatric reference centre with de-novo kidney abscesses from 2011 to 2022, diagnosed through imaging (ultrasonography or computed tomography). VCUG's clinical utility was assessed by exploring outcomes related to interventions. RESULTS: Among the 17 patients (median age 9 months, IQR; 6 months-6 years), VCUG identified VUR in 7 (41%; 95% CI: 18-65%), including two with grade IV-V. Median abscess size was 19 mm (IQR; 14-27). 7/8 (88%) children with DMSA scan presented scars, including 4 with hypofunctioning (20%-44%), and one with a non-functioning kidney. Scarring on the DMSA scan was similar regardless of identified VUR. Six children had subsequent pyelonephritis. Three of the remaining 11 had grade I-III and two IV-V VUR. Surgery was required in four children overall: three for recurrent pyelonephritis and one for high-grade VUR and scars. CONCLUSION: Among initial kidney abscess cases, 41% had VUR, similar to children experiencing their first uncomplicated pyelonephritis. VCUG results guided antibiotic prophylaxis but not surgical decisions. We suggest considering VCUG following recurrent pyelonephritis/kidney abscess and/or kidney scarring.

The genetic landscape and clinical spectrum of nephronophthisis and related ciliopathies.

Nephronophthisis (NPH) is an autosomal-recessive ciliopathy representing one of the most frequent causes of kidney failure in childhood characterized by a broad clinical and genetic heterogeneity. Applied to one of the worldwide largest cohorts of patients with NPH, genetic analysis encompassing targeted and whole exome sequencing identified disease-causing variants in 600 patients from 496 families with a detection rate of 71%. Of 788 pathogenic variants, 40 known ciliopathy genes were identified. However, the majority of patients (53%) bore biallelic pathogenic variants in NPHP1. NPH-causing gene alterations affected all ciliary modules defined by structural and/or functional subdomains. Seventy six percent of these patients had progressed to kidney failure, of which 18% had an infantile form (under five years) and harbored variants affecting the Inversin compartment or intraflagellar transport complex A. Forty eight percent of patients showed a juvenile (5-15 years) and 34% a late-onset disease (over 15 years), the latter mostly carrying variants belonging to the Transition Zone module. Furthermore, while more than 85% of patients with an infantile form presented with extra-kidney manifestations, it only concerned half of juvenile and late onset cases. Eye involvement represented a predominant feature, followed by cerebellar hypoplasia and other brain abnormalities, liver and skeletal defects. The phenotypic variability was in a large part associated with mutation types, genes and corresponding ciliary modules with hypomorphic variants in ciliary genes playing a role in early steps of ciliogenesis associated with juvenile-to-late onset NPH forms. Thus, our data confirm a considerable proportion of late-onset NPH suggesting an underdiagnosis in adult chronic kidney disease.

Benefits of BNP/NT-proBNP serum level evaluation for dry weight adjustment in pediatric hemodialysis patients.

BACKGROUND: Dry weight (DW) adjustment in children on hemodialysis (HD) can be challenging. It relies on clinical evaluation and additional supports. Our aim was to study the benefits of cardiac biomarker assessment, in addition to the more commonly used technique, bioimpedance spectroscopy (BIS), and clinical signs for DW prescription in pediatric HD patients. METHOD: Observational study including 41 children on HD in three pediatric HD centers in the Paris region. During one session, BIS was performed before the session and serum levels of BNP and NT-proBNP were analyzed before and after the session. RESULTS: Median pre-dialysis level of BNP was 87 ng/L [24-192] and NT-proBNP 968 ng/L [442-4828]. Cardiac biomarker levels showed positive correlation with the BIS hydration status evaluation (p = 0.004). The most appropriate cutoff for pre-dialysis BNP to detect significant overhydration (OH) was 165 ng/L (sensitivity 0.67, specificity 0.84). Based on the BIS evaluation, only 32% of patients with high blood pressure (BP) had OH, whereas in the normal BP group, 33% had significant OH. CONCLUSIONS: DW prescription for children on HD should not only rely on clinical evaluation, particularly BP, but should also include additional helpful parameters. BIS is well-validated in children, but it has limitations in non-cooperative patients, and its cost can limit its use in some settings. Cardiac biomarkers, especially BNP, were well-correlated to hydration status evaluated by BIS, and thus could add valuable information for individual patient management and DW assessment. A higher resolution version of the Graphical abstract is available as Supplementary information.

To biopsy or not to biopsy: Henoch-Schönlein nephritis in children, a 5-year follow-up study.

BACKGROUND: The prognosis of Henoch-Schönlein purpura (HSP), IgA vasculitis, depends on kidney involvement. There is no consensus on the initiation of treatment for HSP nephritis (HSPN). Some centres start treatment before performing a kidney biopsy (KB) while in others, treatment is dictated by the importance of the clinical, biological and histological signs. The aim of this study was to evaluate which of these two approaches is associated with a better kidney outcome at 5-year follow-up. METHODS: This multicentre, retrospective, nonrandomised study included children treated for HSPN between 2006 and 2010 in a French paediatric nephrology unit. One group had an early KB at diagnosis (before starting treatment or in the 15 following days). In the second group, initial treatment was decided without performing a KB. RESULTS: Among the 107 children included, 63.5% had an early KB at diagnosis. Follow-up at 5 years was completed in 44 children (28 KB at diagnosis, 16 no KB at diagnosis). Median urine protein/creatinine at 5 years was 2.5 mg/mmol in the early biopsy diagnosis group and 12.5 mg/mmol in the non-biopsy group. An antiproteinuric treatment was given, at 5 years, to 35.7% of the early biopsy at diagnosis children and in 62.5% of the non-biopsied children. CONCLUSIONS: Children with early KB at diagnosis seem to have a better renal outcome at 5 years compared to those without an early biopsy at diagnosis or biopsied later. However, this is a small patient cohort and data are missing. Further work is needed to build consensual guidelines on the management of HSPN in children.

Benign and malignant proliferation in idiopathic nephrotic syndrome: a French cohort study.

BACKGROUND: There seems to be a possible link between nephrotic syndrome (NS) and lymphoproliferative syndrome, but it remains poorly understood. METHODS: This multicentric and retrospective study focuses on children, who developed idiopathic NS and malignant or benign proliferation between 2000 and 2021. RESULTS: Eleven patients were included, with a median age of 4 years. Only one had a steroid-resistant nephrotic syndrome (SRNS). The maintenance therapy before the proliferation was in majority tacrolimus or mycophenolate mofetil (MMF), but three patients did not receive treatments. The proliferation was mainly a Hodgkin's lymphoma (45%) or a lymphoproliferative disease (36%), in a median time after the NS of two years. Viruses were found in seven cases (EBV in five cases and HHV-8 in two). CONCLUSION: The association between proliferative syndrome and idiopathic NS may not be fortuitous, possibly with a common lymphocytic disturbance. Genetic analyses could improve the comprehension of these manifestations in the future. A higher resolution version of the Graphical abstract is available as Supplementary information.

Induction therapy for pediatric onset class IV lupus nephritis: Mycophenolate Mofetil versus Cyclophosphamide.

OBJECTIVES: Class IV lupus nephritis (LN) is one of the most frequent and severe types of involvement in pediatric systemic lupus erythematosus. Gold standard treatment consists of intravenous (i.v.) Cyclophosphamide (CYC) associated with corticosteroids. Recent studies in adults have shown similar efficacy of oral Mycophenolate Mofetil (MMF) with fewer adverse events. Our aim was to compare the efficacy and tolerance of CYC and MMF as induction therapy in children with class IV LN. METHODS: We conducted a retrospective study of children diagnosed with class IV LN who started oral MMF or i.v. CYC treatment at Necker Enfants Malades Hospital (Paris, France). RESULTS: The study included 33 patients, 17 treated with oral MMF (51%) and 16 with i.v. CYC (48%). The characteristics at treatment induction did not significantly differ between the two groups except for the neurological involvement, that was only present in the CYC group. Complete remission was obtained in 9/17 (53%) children treated with MMF versus 10/16 (71%) treated with CYC (p = 0.46). Relapse was observed in 59% of patients receiving MMF versus 50% receiving CYC (p = 0.87), after a median of 3.4 years and 4.7 years after the beginning of treatment, respectively (p = 0.41). During the 6.5 years of follow-up, we observed no significant difference regarding the number of treatment-related adverse events between the two groups (p = 0.48). CONCLUSION: We report similar efficacy and tolerance of MMF or CYC as induction therapy of class IV LN in children. However, the long-term adverse events such as infertility could not be systematically evaluated in this retrospective pediatric study. Overall, however, considering the long-term safety profile reported in the literature, we suggest that MMF may be used as first-line induction therapy in LN.