Incidental finding of acquired cystic kidney disease associated renal cell carcinoma in an adolescent with kidney failure.

Acquired cystic kidney disease (ACKD) can occur in patients with chronic kidney disease and kidney failure, and its incidence increases with the duration of dialysis. In adults, ACKD is less common in the pre-dialysis group (~ 7%), but its incidence can be as high as 80% for those who are on dialysis for more than ten years. There is, however, very little information about the prevalence of ACKD in children. We report a case of malignant transformation of ACKD following a kidney transplant, highlighting the importance of surveillance of the native kidneys in paediatric patients who have been in long-term kidney replacement therapy.

Levamisole in childhood idiopathic nephrotic syndrome: new promises, and advocacy for global access.

In the current issue of Kidney International, Sinha et al. present data from an open-label, noninferior, randomized controlled trial comparing 12-months of alternate-day prednisolone, given daily during infection, versus levamisole, in children with frequently relapsing or steroid-dependent nephrotic syndrome. This study suggests that both of these strategies are efficacious and safe. Results of this study should redefine the role of levamisole in future guidelines, and a call for global availability of levamisole should be advocated.

Renal relapse in children and adolescents with childhood-onset lupus nephritis: a 20-year study.

OBJECTIVES: There is little data on renal relapse in childhood-onset LN (cLN). We investigate the incidence, predictive factors and outcomes related to renal relapse. METHODS: We conducted a retrospective cohort study of all cLN diagnosed at ≤18 years between 2001-2021 to investigate the incidence and outcomes related to renal relapse. RESULTS: Ninety-five Chinese cLN patients (91% proliferative LN) were included. Induction immunosuppression was prednisolone and CYC [n = 36 (38%)] or MMF [n = 33 (35%)]. Maintenance immunosuppression was prednisolone and MMF [n = 53 (54%)] or AZA [n = 29 (31%)]. The rates of complete remission/partial remission (CR/PR) at 12 months were 78.9%/7.4%. Seventy renal relapses occurred in 39 patients over a follow-up of 10.2 years (s.d. 5.9) (0.07 episode/patient-year). Relapse-free survival was 94.7, 86.0, 80.1, 71.2, 68.3, 50.3 and 44.5% at 1, 2, 3, 4, 5, 10 and 20 years, respectively. Multivariate analysis showed that LN diagnosis <13.1 years [adjusted hazard ratio (HRadj) 2.59 995% CI 1.27, 5.29), P = 0.01], AZA maintenance [HRadj 2.20 (95% CI 1.01, 4.79), P = 0.05], PR [HRadj 3.9 (95% CI 1.03, 9.19), P = 0.01] and non-remission [HRadj 3.08 (95% CI 1.35, 11.3), P = 0.04] at 12 months were predictive of renal relapse. Renal relapse was significantly associated with advanced chronic kidney disease (stages 3-5) and end-stage kidney disease (17.9% vs 1.8%, P < 0.01). Furthermore, patients with renal relapse showed an increased incidence of infections (30.8% vs 10.7%, P = 0.02), osteopenia (38.5% vs 17.9%, P = 0.04) and hypertension (30.8% vs 7.1%, P < 0.01). CONCLUSION: Renal relapse is common among cLN, especially among young patients, and is associated with an increased incidence of morbidity and mortality. Attaining CR and the use of MMF appear to decrease the incidence of renal relapse.

Managing Lupus Nephritis in Children and Adolescents.

Lupus nephritis is an important manifestation of systemic lupus erythematosus, which leads to chronic kidney disease, kidney failure, and can result in mortality. About 35%-60% of children with systemic lupus erythematosus develop kidney involvement. Over the past few decades, the outcome of patients with lupus nephritis has improved significantly with advances in immunosuppressive therapies and clinical management. Nonetheless, there is a paucity of high-level evidence to guide the management of childhood-onset lupus nephritis, because of the relatively small number of patients at each centre and also because children and adolescents are often excluded from clinical trials. Children and adults differ in more ways than just size, and there are remarkable differences between childhood- and adult-onset lupus nephritis in terms of disease severity, treatment efficacy, tolerance to medications and most importantly, psychosocial perspective. In this article, we review the 'art and science' of managing childhood-onset lupus nephritis, which has evolved in recent years, and highlight special considerations in this specific patient population.

Humoral and Cellular Immunogenicity of 3 Doses of BNT162b2 in Children With Kidney Diseases.

Introduction: Patients with severe kidney diseases are at risk of complications from COVID-19; however, little is known about the effectiveness of COVID-19 vaccines in children and adolescents with kidney diseases. Methods: We investigated the immunogenicity and safety of an accelerated 3-dose primary series of COVID-19 vaccination among 59 pediatric patients with chronic kidney disease (CKD) (mean age 12.9 years; 30 male) with or without immunosuppression, dialysis, or kidney transplant. Dosage was 0.1 ml BNT162b2 to those aged 5 to 11 years, and 0.3 ml BNT162b2 to those aged 11 to 18 years. Results: Three doses of either vaccine type elicited significant antibody responses that included spike receptor-binding domain (S-RBD) IgG (90.5%-93.8% seropositive) and surrogate virus neutralization (geometric mean sVNT% level, 78.6%-79.3%). There were notable T cell responses. Weaker neutralization responses were observed among those on immunosuppression, especially those receiving higher number of immunosuppressants or on mycophenolate mofetil. Neutralization was reduced against Omicron BA.1 compared to wild type (WT, i.e., ancestral) (post-dose 3 sVNT% level; 82.7% vs. 27.4%; P < 0.0001). However, the T cell response against Omicron BA.1 was preserved, which likely confers protection against severe COVID-19. Infected patients exhibited hybrid immunity after vaccination, as evidenced by the higher Omicron BA.1 neutralization response among these infected patients who received 2 doses compared with those who were uninfected. Generally mild or moderate adverse reactions following vaccines were reported. Conclusion: An accelerated 3-dose primary series with BNT162b2 is immunogenic and safe in young children and adolescents with kidney diseases.

Short duration of parenteral antibiotics in infants with urinary tract infections.

Objectives: Current guidelines by the Canadian Paediatric Society on treating urinary tract infections (UTIs) exclude infants ≤ 60 days old. There is considerable practice variability in this age group, especially around the optimal duration of parenteral antibiotics. The study aimed to assess local practice patterns, and the safety of a short course (≤3 days) of parenteral antibiotics in young infants. Methods: In this retrospective cohort study, 95 infants (≤60 days) with confirmed UTIs were identified at British Columbia Children's Hospital. Patients receiving short (≤3 days) and long (>3 days) duration of parenteral antibiotics were compared. Outcomes of interest included urinary tract infection recurrence within 30 days, hospital length of stay (LOS), representation, and readmission. Results: Twenty infants (21%) received a short course of parenteral antibiotics. These infants were older (median 47 days versus 28 days) and non-bacteremic. Urinary tract infection recurrence was identified in 8 patients (8%), of which 7 were treated with a long duration (P = 1.0). Patients treated with a short duration had a significantly shorter LOS, with a mean difference of 4.21 days [95% CI: 3.37 to 5.05] (P < 0.001). All five (5%) bacteremic patients were treated exclusively with parenteral antibiotics. Conclusions: In a Canadian setting, a short course of parenteral antibiotics is safe in young, non-bacteremic infants with UTIs. Despite substantial evidence, local practice patterns suggest a tendency towards prescription of long courses, providing an opportunity for quality improvement.

Long-term outcomes with rituximab as add-on therapy in severe childhood-onset lupus nephritis.

BACKGROUND: Long-term data pertaining to rituximab as add-on therapy in childhood-onset lupus nephritis (cLN) is scarce. METHODS: A retrospective cohort study was conducted on all patients with proliferative cLN, diagnosed ≤ 18 years and between 2005 and 2021, who received rituximab for LN episodes that were life/organ threatening and/or treatment resistant to standard immunosuppression. RESULTS: Fourteen patients with cLN (female, n = 10) were included, with median follow-up period of 6.9 years. LN episodes (class III, n = 1; class IV, n = 11; class IV + V, n = 2) requiring rituximab occurred at 15.6 years (IQR 12.8-17.3), urine protein:creatinine ratio was 8.2 mg/mg (IQR 3.4-10.1) and eGFR was 28 mL/min/1.73 m2 (IQR 24-69) prior to rituximab treatment. Ten and four patients received rituximab at 1500 mg/m2 and 750 mg/m2, which were given at 46.5 days (IQR 19-69) after commencement of standard therapies. Treatment with rituximab resulted in improvements in proteinuria (ps < 0.001), eGFR (ps < 0.01) and serological parameters, including haemoglobin levels, complement 3 levels and anti-dsDNA antibodies, compared with baseline. Rates of complete/partial remission at 6-, 12- and 24-month post-rituximab were 28.6/42.8%, 64.2/21.4% and 69.2/15.3%. All three patients who required acute kidney replacement therapy became dialysis-free after rituximab. Relapse rate following rituximab was 0.11 episodes/patient-year. There was no lethal complication or severe infusion reaction. Hypogammaglobulinaemia was the most frequent complication (45%) but was mostly asymptomatic. Neutropenia and infections were observed in 20% and 25% of treatments. Upon last follow-up, three (21%) and two (14%) patients developed chronic kidney disease (stage 2, n = 2; stage 4; n = 1) and kidney failure, respectively. CONCLUSION: Add-on rituximab is an effective and safe rescue therapy for cLN patients with life-/organ-threatening manifestations or treatment-resistance. A higher resolution version of the Graphical abstract is available as Supplementary information.

Acute kidney injury in children with haematological malignancy: a territory-wide study.

BACKGROUND: In onco-nephrology, data on acute kidney injury (AKI) among children with haematological malignancies are scarce. METHODS: A retrospective cohort study of all patients in Hong Kong diagnosed with haematological malignancies from 2019 to 2021 before 18 years of age, was conducted to investigate the epidemiology, risk factors and clinical outcomes of AKI during the first year of treatment. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. RESULTS: We included 130 children with haematological malignancy at median age of 9.4 years (IQR, 3.9-14.1). Of these patients, 55.4% were acute lymphoblastic leukemia (ALL), 26.9% were lymphoma and 17.7% were acute myeloid leukemia (AML). Thirty-five patients (26.9%) developed 41 AKI episodes during the first year of diagnosis, corresponding to 32 episodes per 100-patient-year. A total of 56.1% and 29.2% of the AKI episodes occurred during induction and consolidation chemotherapy respectively. Septic shock (n = 12, 29.2%) was the leading cause of AKI; 21 episodes (51.2%) were stage 3 AKI; 12 episodes (29.3%) were stage 2 AKI; and 6 patients required continuous kidney replacement therapies. Tumor lysis syndrome and impaired baseline kidney function were significantly associated with AKI on multivariate analysis (P = 0.01). History of AKI was associated with chemotherapy postponement (37.1% vs. 16.8%, P = 0.01), worse 12-month patient survival (77.1% vs. 94.7%, log rank P = 0.002) and lower disease remission rate at 12-month (68.6% vs. 88.4%, P = 0.007), compared to patients without AKI. CONCLUSION: AKI is a common complication during treatment of haematological malignancies which is associated with worse treatment outcomes. A regular and dedicated surveillance program for at-risk patients should be studied in children with haematological malignancies for prevention and early detection of AKI. A higher resolution version of the Graphical abstract is available as Supplementary information.

A multicenter retrospective study of calcineurin inhibitors in nephrotic syndrome secondary to podocyte gene variants.

While 44-83% of children with steroid-resistant nephrotic syndrome (SRNS) without a proven genetic cause respond to treatment with a calcineurin inhibitor (CNI), current guidelines recommend against the use of immunosuppression in monogenic SRNS. This is despite existing evidence suggesting that remission with CNI treatment is possible and can improve prognosis in some cases of monogenic SRNS. Herein, our retrospective study assessed response frequency, predictors of response and kidney function outcomes among children with monogenic SRNS treated with a CNI for at least three months. Data from 203 cases (age 0-18 years) were collected from 37 pediatric nephrology centers. Variant pathogenicity was reviewed by a geneticist, and 122 patients with a pathogenic and 19 with a possible pathogenic genotype were included in the analysis. After six months of treatment and at last visit, 27.6% and 22.5% of all patients respectively, demonstrated partial or full response. Achievement of at least partial response at six months of treatment conferred a significant reduction in kidney failure risk at last follow-up compared to no response (hazard ratio [95% confidence interval] 0.25, [0.10-0.62]). Moreover, risk of kidney failure was significantly lower when only those with a follow-up longer than two years were considered (hazard ratio 0.35, [0.14-0.91]). Higher serum albumin level at CNI initiation was the only factor related to increased likelihood of significant remission at six months (odds ratio [95% confidence interval] 1.16, [1.08-1.24]). Thus, our findings justify a treatment trial with a CNI also in children with monogenic SRNS.

Long-Term Outcomes of Children and Adolescents With Biopsy-Proven Childhood-Onset Lupus Nephritis.

Introduction: Long-term data pertaining to childhood-onset lupus nephritis (cLN) remain extremely scarce. Methods: We conducted a retrospective cohort study of biopsy-proven cLN with onset age <18 years diagnosed from 2001 to 2020 to ascertain the long-term patient and kidney survival rates, and the incidence of advanced chronic kidney disease (CKD) (estimated glomerular filtration rate [eGFR] <60 ml/min per 1.73 m2). Results: A total of 92 subjects (78 female; age 13.7 ± 3.3 years; all Chinese) were included, with follow-up duration of 10.3 years (interquartile range, 5.8-15.9). Of these, 83 children (90%) had proliferative lupus nephritis (LN) (Class III/IV ± V). Mycophenolate was used for induction in 36%, whereas 34% received cyclophosphamide (CYC); 55% received mycophenolate as maintenance immunosuppression. The rates of complete remission (CR) and partial remission (PR) at 6 months and 12 months, respectively, were 65% and 20% and 78% and 8%. Two patients died (mortality rate 2.1/1000 patient-years), with a standardized mortality ratio of 22.3. Three patients (3.2%) developed end-stage kidney disease (ESKD), and advanced CKD occurred in 5 patients (5.4%). Survival rates without advanced CKD, ESKD, or death were 96.7%, 94.2%, 92.7%, 83.2% and 83.2% at 1 year, 5 years, 10 years, 15 years, and 20 years, respectively. Multivariate analysis revealed that severe kidney failure necessitating dialysis at presentation (adjusted hazard ratio 37.7, 95% confidence interval [CI] 4.0-355.6, P = 0.002), nonresponse (NR) after 12 months of treatment (adjusted hazard ratio 11.2, 95% CI 2.3-54.9, P = 0.003), and multiple nephritis flares (adjusted hazard ratio 2.6, 95% CI 1.1-6.2, P = 0.03) were predictive of advanced CKD, ESKD, or death. Other adverse outcomes included infections (2.9 episodes/100 patient-years), osteopenia (32%), hypertension (17%), short stature (14%), and avascular necrosis (7%). Conclusion: The long-term outcomes of cLN appeared to have improved in the present era with effective immunosuppression, cautious drug tapering, and assurance of medication adherence. There is still an unacceptably high prevalence of adverse outcomes.

Use of Rituximab in Childhood Idiopathic Nephrotic Syndrome.

Rituximab is an established therapy in children with idiopathic nephrotic syndrome to sustain short- to medium-term disease remission and avoid steroid toxicities. Recent trials focus on its use as a first-line agent among those with milder disease severity. Rituximab is used in multidrug refractory nephrotic syndrome and post-transplant disease recurrence, although the evidence is much less substantial. Available data suggest that the treatment response to rituximab depends on various patient factors, dosing regimen, and the concomitant use of maintenance immunosuppression. After repeated treatments, patients are found to have an improving response overall with a longer relapse-free period. The drug effect, however, is not permanent, and 80% of patients eventually relapse and many will require an additional course of rituximab. This underpins the importance of understanding the long-term safety profile on repeated treatments. Although rituximab appears to be generally safe, there are concerns about long-term hypogammaglobulinemia, especially in young children. Reliable immunophenotyping and biomarkers are yet to be discovered to predict treatment success, risk of both rare and severe side effects, e.g. , persistent hypogammaglobulinemia, and guiding of redosing strategy. In this review, we highlight recent advances in the use of rituximab for childhood nephrotic syndrome and how the therapeutic landscape is evolving.

Outcomes and perception of cloud-based remote patient monitoring in children receiving automated peritoneal dialysis: a prospective study.

BACKGROUND: Remote patient monitoring (RPM) for automated peritoneal dialysis (APD) may improve clinical outcomes. Paediatric data, however, remain extremely scarce. METHODS: We conducted a prospective observational study of children (0-18 years) receiving APD with cloud-based RPM over two 24-week periods (pre- and post-RPM). Primary outcomes were unplanned hospitalizations and fluid management. Children receiving APD without RPM (non-RPM) were included as control. RESULTS: Seven patients (6 females) receiving APD were enrolled in the RPM programme at 11.3 years (IQR 2.6-17.1). Main indications for RPM included history of fluid overload (n = 3) and non-adherence (n = 2). Ten children were included in the non-RPM group (6 females; 16.9 years, IQR 12.8-17.6). Four patients (57.1%, 95% CI 22.5-100%) experienced fewer unplanned hospitalizations and 5 patients (71.4%, 95% CI 34.1-100%) had shorter hospital stays during the post-RPM period. The hospitalization rates and length of stay were reduced by 45% and 42%, respectively. The higher hospitalization rates among the RPM group, compared to the non-RPM group, were no longer observed following implementation of RPM. There was a significant increase in ultrafiltration (565.6 ± 248.7 vs. 501.7 ± 286.6 ml/day, p = 0.03) and reduction in systolic blood pressure (114.1 ± 12.6 vs. 119.9 ± 11.19 mmHg, p = 0.02) during the post-RPM period. All patients demonstrated satisfactory adherence. Although quality of life (PedsQL 3.0 ESRD module) was not different pre- and post-RPM, all patients agreed in the questionnaires that the use of RPM improved their quality of life and sense of security. CONCLUSIONS: In conclusion, RPM in children receiving APD is associated with fewer and shorter unplanned hospitalizations, improved fluid management and favourable adherence to PD. A higher resolution version of the Graphical abstract is available as Supplementary information.

Epidemiology and outcomes of pediatric transplant-associated thrombotic microangiopathy in Hong Kong.

BACKGROUND: Transplant-associated thrombotic microangiopathy (TA-TMA) is an under-recognized yet potentially devastating complication of hematopoietic stem cell transplantation (HSCT) which had increased awareness in recent years. This report summarizes the demographics and outcomes of pediatric TA-TMA in Hong Kong. METHODS: All patients aged below 18 years who underwent HSCT in the Hong Kong Children's Hospital and were diagnosed to have TA-TMA during the 2-year period from April 1, 2019 to March 31, 2021 were included. RESULTS: A total of 73 transplants (51 allogeneic and 22 autologous) in 63 patients had been performed. Six patients (four males and two females) developed TA-TMA at a median duration of 2.5 months post-HSCT. The incidence rate was 9.52%. Of the six TA-TMA patients, five underwent allogenic one underwent autologous HSCT, respectively. Three of them were histologically proven. All four patients with cyclosporine had stopped the drug once TA-TMA was suspected. Median six doses of eculizumab were administered to five out of six patients. Three patients died (two due to fungal infection and one due to acute-on-chronic renal failure) within 3 months upon diagnosis of TA-TMA. Among three survivors, two stabilized with mild stage 2 chronic kidney disease (CKD) while the other suffered from stage 5 end-stage CKD requiring lifelong dialysis. CONCLUSION: In conclusion, recognition and diagnosis of TA-TMA are challenging. Early recognition and prompt administration of complement blockage with eculizumab may be beneficial in selected cases. Further prospective research studies are recommended to improve the management and outcomes of TA-TMA.

Embolisation of an aneurysmal high-flow renal arteriovenous fistula in a paediatric patient: simultaneous arterial and venous approach.

BACKGROUND: A large aneurysmal renal arteriovenous fistula (AVF) can cause hypokalaemic hypertension due to activation of renin-aldosterone system due to steal effect from renal parenchyma. In comparison to nephrectomy, endovascular embolisation of renal AVF is minimally invasive and can be nephron sparing, thus preserving renal function. However, such embolisation is technically challenging and can be associated with high risk of embolic migration. CASE PRESENTATION: We present a case of successful embolisation of a large aneurysmal renal AVF in a 11-year-old girl. The AVF was initially treated with coil embolization via transarterial route, resulting in partial migration of coil into inferior vena cava. After removal of the migrated coil via transvenous snaring, coils were deployed simultaneously via transarterial and transvenous routes to prevent migration. AVF flow dampened but residual flow persisted at 1 month follow up. A second embolization session with additional coil deployment and N-butyl cyanoacrylate (NBCA) injection resulted in successful occlusion of the AVF. At 3 months follow up, the girl's blood pressure and serum potassium level have normalized without need of antihypertensive agent or potassium supplements. CONCLUSION: Endovascular embolisation can be an effective nephron sparing treatment for large aneurysmal renal AVF. This is particularly important in paediatric patients as most renal function can be preserved with their expected longer life span. Risk of coil migration can be controlled by simultaneous transarterial and transvenous deployment. Complete occlusion of AVF can be aided by additional use of NBCA.

Percutaneous ultrasound-guided renal biopsies in a paediatric population: comparison of coaxial and non-coaxial techniques using 18-gauge core biopsy needles.

BACKGROUND: Percutaneous ultrasound-guided biopsy is performed in paediatric patients for evaluation of diffuse renal parenchymal disease. When compared with the non-coaxial technique, the coaxial technique has the advantages of obtaining multiple tissue cores via a single capsular puncture and post-biopsy tract embolisation. OBJECTIVES: To compare the coaxial and non-coaxial techniques of percutaneous ultrasound (US)-guided biopsy of native kidney parenchyma in children and adolescents with renal disease. MATERIALS AND METHODS: We retrospectively identified consecutive patients who underwent percutaneous US-guided renal biopsy using an 18-gauge core biopsy needle from July 2019 to July 2021 in a single tertiary paediatric nephrology centre. Focal renal tumour biopsy and transplant kidney biopsy were excluded. The total glomerular yield, specimen adequacy, complication rate and procedural time between the coaxial and non-coaxial groups were compared. RESULTS: There were 34 percutaneous US-guided renal biopsies: 22 using a coaxial technique and 12 using a non-coaxial technique. The total median glomerular yield obtained was higher in the coaxial group (coaxial=37.9; non-coaxial=22.2; P=0.02). No statistically significant difference was noted between specimen adequacy (coaxial=100%; non-coaxial=91.7%; P=0.35). While no statistically significant difference was detected for overall complication rates (coaxial=13.6%; non-coaxial=41.7%; P=0.09), the coaxial group had a lower rate of haemorrhagic complications (coaxial=4.5%; non-coaxial=41.7%; P=0.01). One patient in the non-coaxial group had post-biopsy haemorrhage requiring embolisation. The procedural time was shorter in the coaxial group (coaxial=26.3 ± 7.0 min; non-coaxial=51.3 ± 11.5 min; P<0.001). CONCLUSION: Percutaneous US-guided renal biopsy in children using the coaxial technique has significantly higher total glomerular yield, shorter procedural time and fewer haemorrhagic complications, compared to biopsies using the non-coaxial technique.