Anti-factor B antibodies in atypical hemolytic uremic syndrome

BACKGROUND

The etiology of atypical hemolytic uremic syndrome (aHUS) is unknown in 30-40% of patients. Anti-factor B (FB) antibodies are reported in C3 glomerulopathy (C3G) and immune-complex membranoproliferative glomerulonephritis (IC-MPGN), though not in aHUS.

METHODS

We screened patients < 18-year-old from cohorts of aHUS and C3G/idiopathic IC-MPGN. Anti-FB IgG antibodies were measured by ELISA and confirmed by Western blot. Normative levels were based on antibody levels in 103 healthy blood donors.

RESULTS

Prevalence of anti-FB antibodies was 9.7% (95% CI 6.1-14.5%; n = 21) in 216 patients with aHUS, including 11.5% (95% CI 6.4-18.5%; n = 14) in anti-FH associated aHUS and 11.8% (95% CI 4.4-23.9%; n = 6) in patients without a definitive genetic or autoimmune etiology. Patients with significant genetic variants did not show anti-FB antibodies. In patients with concomitant anti-FB and anti-FH antibodies, median anti-FH titers were higher (11,312 AU/mL vs. 4920 AU/mL; P = 0.04). Anti-FB antibody titer correlated with disease severity (hemoglobin and platelets; P < 0.05), declined following plasma exchange and increased during relapse. While 4/64 patients with C3G (6.3%) and 1/17 with IC-MPGN showed anti-FB antibodies, titers were higher in aHUS (544.8 AU/mL vs. 1028.8 AU/mL; P = 0.003).

CONCLUSION

Anti-FB antibodies are present in 6-10% of patients with aHUS and C3G/IC-MPGN, with higher titers in the former. The diagnostic and therapeutic implication of anti-FB antibodies in aHUS needs confirmation and further studies. The study shows propensity for autoantibody generation and co-existence of multiple risk factors for aHUS in Indian children.

Evidence-based clinical practice guideline for management of urinary tract infection and primary vesicoureteric reflux

We present updated, evidence-based clinical practice guidelines from the Indian Society of Pediatric Nephrology (ISPN) for the management of urinary tract infection (UTI) and primary vesicoureteric reflux (VUR) in children. These guidelines conform to international standards; Institute of Medicine and AGREE checklists were used to ensure transparency, rigor, and thoroughness in the guideline development. In view of the robust methodology, these guidelines are applicable globally for the management of UTI and VUR. Seventeen recommendations and 18 clinical practice points have been formulated. Some of the key recommendations and practice points are as follows. Urine culture with > 104 colony forming units/mL is considered significant for the diagnosis of UTI in an infant if the clinical suspicion is strong. Urine leukocyte esterase and nitrite can be used as an alternative screening test to urine microscopy in a child with suspected UTI. Acute pyelonephritis can be treated with oral antibiotics in a non-toxic infant for 7-10 days. An acute-phase DMSA scan is not recommended in the evaluation of UTI. Micturating cystourethrography (MCU) is indicated in children with recurrent UTI, abnormal kidney ultrasound, and in patients below 2 years of age with non-E. coli UTI. Dimercaptosuccinic acid scan (DMSA scan) is indicated only in children with recurrent UTI and high-grade (3-5) VUR. Antibiotic prophylaxis is not indicated in children with a normal urinary tract after UTI. Prophylaxis is recommended to prevent UTI in children with bladder bowel dysfunction (BBD) and those with high-grade VUR. In children with VUR, prophylaxis should be stopped if the child is toilet trained, free of BBD, and has not had a UTI in the last 1 year. Surgical intervention in high-grade VUR can be considered for parental preference over antibiotic prophylaxis or in children developing recurrent breakthrough febrile UTIs on antibiotic prophylaxis.

An open label non-inferiority randomized controlled trial evaluated alternate day prednisolone given daily during infections vs. levamisole in frequently relapsing nephrotic syndrome

Initial therapies for children with frequently relapsing nephrotic syndrome include alternate-day prednisolone that is given daily during infections, or levamisole. In this open label, non-inferiority trial, 160 patients, 2 to 18-years-old with frequent relapses, were randomly assigned to receive either prednisolone (0.5-0.7 mg/kg/alternate-day, given daily during infections), or levamisole (2-2.5 mg/kg/alternate-days) for one-year. Patients with relapses on alternate day prednisolone at over 1 mg/kg, prior use of potent steroid-sparing therapies, eGFR under 60 ml/min/1.73 m2 and significant steroid toxicity were excluded. Primary outcome was the proportion of patients with frequent relapses, defined as three-relapses in one-year, or two-relapses within six-months if associated with significant steroid toxicity or loss to follow up. Eighty patients each were randomized to receive prednisolone and levamisole. Baseline features showed preponderance of young patients presenting within two-years of disease onset. On intention-to-treat analysis, frequent relapses were more common in patients administered prednisolone (40% versus 22.5%; risk difference 17.5%; 95% confidence interval 3.4-31.6%). Prednisolone was not non-inferior to levamisole in preventing frequent relapses. However, the two groups showed similar proportions of patients in sustained remission, comparable frequency of relapses, and low frequency of adverse events. The decline in steroid requirement from baseline was higher in the levamisole group. Per-protocol analysis showed similar results. These results have implications for choice of therapy for frequently relapsing nephrotic syndrome. Although therapy with alternate-day prednisolone was not non-inferior to levamisole in preventing frequent relapses, both therapies were effective in other outcome measures. Thus, levamisole was relatively steroid-sparing and may be preferred in patients at risk of steroid toxicity.

Furosemide stress test to predict acute kidney injury progression in critically ill children

BACKGROUND

Furosemide stress test (FST) is a novel functional biomarker for predicting severe acute kidney injury (AKI); however, pediatric studies are limited.

METHODS

Children 3 months to 18 years of age admitted to the intensive care unit (ICU) of a tertiary care hospital from Nov 2019 to July 2021 were screened and those who developed AKI stage 1 or 2 within 7 days of admission underwent FST (intravenous furosemide 1 mg/kg). Urine output was measured hourly for the next 6 h; a value > 2 ml/kg within the first 2 h was deemed furosemide responsive. Other biomarkers like plasma neutrophil gelatinase-associated lipocalin (NGAL) and proenkephalin (PENK) were also evaluated.

RESULTS

Of the 480 admitted patients, 51 developed AKI stage 1 or 2 within 7 days of admission and underwent FST. Nine of these patients were furosemide non-responsive. Thirteen (25.5%) patients (eight of nine from FST non-responsive group) developed stage 3 AKI within 7 days of FST, nine (17.6%) of whom (seven from non-responsive group) required kidney support therapy (KST). FST emerged as a good biomarker for predicting stage 3 AKI and need for KST with area-under-the-curve (AUC) being 0.93 ± 0.05 (95% CI 0.84-1.0) and 0.96 ± 0.03 (95% CI 0.9-1.0), respectively. FST outperformed NGAL and PENK in predicting AKI stage 3 and KST; however, the combination did not improve the diagnostic accuracy.

CONCLUSIONS

Furosemide stress test is a simple, inexpensive, and robust biomarker for predicting stage 3 AKI and KST need in critically ill children. Further research is required to identify the best FST cut-off in children.

Management of Urinary Tract Infections and Vesicoureteric Reflux: Key Updates From Revised Indian Society of Pediatric Nephrology Guidelines 2023

Non-specific symptoms and difficulty in collecting urine specimens make the diagnosis of urinary tract infection (UTI) challenging in children. However, timely diagnosis and initiation of therapy are essential to prevent complications. Children with recurrent UTIs require detailed evaluation and follow-up for optimal management. We report key updates from the revised evidence-based practice guidelines of the Indian Society of Pediatric Nephrology for UTIs and primary vesicoureteric reflux.

Abbreviated protocol of plasma exchanges for patients with anti-factor H associated hemolytic uremic syndrome

BACKGROUND

Plasma exchanges (PEX) and immunosuppression are the cornerstone of management of anti-factor H (FH) antibody-associated atypical hemolytic uremic syndrome (aHUS), particularly if access to eculizumab is limited. The duration of therapy with PEX for anti-FH aHUS is empirical.

METHODS

We compared the efficacy of abbreviated PEX protocol (10-12 sessions) in a prospective cohort of patients diagnosed with anti-FH aHUS (2020-2022), to standard PEX protocol (20-22 sessions) in a historical cohort (2016-2019; n = 65). Efficacy was defined as 70% decline in anti-FH titers or fall to ≤ 1300 AU/ml at 4 weeks. Patients in both cohorts received similar immunosuppression with oral prednisolone, IV cyclophosphamide (5 doses) and mycophenolate mofetil. Outcomes included efficacy, rates of hematological remission and adverse kidney outcomes at 1, 3 and 6 months.

RESULTS

Of 23 patients, 8.2 ± 2.1 years old enrolled prospectively, two were excluded for significant protocol deviation. PEX was abbreviated in 18/21 (86%) patients to 11.5 ± 3.3 sessions. Abbreviation failed for lack of hematological remission by day 14 (n = 2) and persistent neurological manifestations (n = 1). All patients in whom PEX was abbreviated achieved > 70% reduction in anti-FH titers at day 28. The percentage fall in anti-FH titers was similar for the abbreviated vs. standard PEX protocols at 1, 3 and 6 months. At last follow-up, at median 50 months and 25 months for standard and abbreviated cohorts, the estimated GFR was similar at 104.8 ± 29.1 vs. 93.7 ± 53.4, respectively (P = 0.42).

CONCLUSION

Abbreviation of the duration of PEX is feasible and efficacious in reducing anti-FH titers. Short-term outcomes were comparable in patients managed by abbreviated and standard PEX protocols.

Clinical features and outcomes of patients with diacylglycerol kinase epsilon nephropathy: a nationwide experience

BACKGROUND

Thrombotic microangiopathy (TMA) is usually caused due to dysregulation of the alternative complement pathway. Rarely, thrombotic microangiopathy is caused by non-complement mediated mutations in diacylglycerol kinase epsilon (DGKE); information about therapy and outcome of these patients is limited.

METHODS

Medical records of patients, younger than 18 years, diagnosed with TMA and variants in DGKE were reviewed to include 12 patients from seven centers. Genetic studies included targeted exome sequencing and multiplex-ligation dependent probe amplification of CFH-CFHR5.

RESULTS

Patients presented at a median age of 11 (7.5, 12.3) months; all were younger than 2 years. All patients had an infectious prodrome; enteroinvasive, enteropathogenic, and enterotoxigenic Escherichia coli were detected in two patients with diarrhea. Chief features included those of microangiopathic hemolysis (n = 11), microscopic hematuria (n = 10), nephrotic range proteinuria (n = 10), hypoalbuminemia (n = 6), elevated total cholesterol (n = 6), and hypocomplementemia (n = 4). Histopathology showed thrombotic microangiopathy (n = 4), overlapping with membranoproliferative pattern of injury (n = 1). At median 3.3 years of follow-up, significant hypertension and/or proteinuria (40%), relapses (66.7%), and death or progression to CKD (60%) were common. Genetic sequencing showed 13 homozygous and compound heterozygous variants (7 pathogenic, 3 likely pathogenic) located throughout DGKE; 11 variants were novel.

CONCLUSIONS

This case series highlights the need to suspect DGKE nephropathy in young patients with TMA, especially those with severe proteinuria. Medium-term outcomes are unsatisfactory with risk of relapses, progressive kidney failure, and death. A higher resolution version of the Graphical abstract is available as Supplementary information.

Variants in complement genes are uncommon in patients with anti-factor H autoantibody-associated atypical hemolytic uremic syndrome

BACKGROUND

Coexisting genetic variants in patients with anti-factor H (FH)-associated atypical hemolytic uremic syndrome (aHUS) have implications for therapy. We estimated the prevalence of complement genetic variants in children with anti-FH aHUS from a prospective nationwide cohort and determined if significant genetic variants impact long-term kidney outcomes.

METHODS

Of 436 patients in the database, 77 consecutive patients, 21 with a relapse and 9 with kidney failure and/or death were included. Targeted sequencing, using a 27-gene panel including CFH, CFI, CFB, C3, CD46, PLG, DGKE, and THBD and multiplex ligation-dependent probe amplification of CFH-CFHR region, was performed. The adverse outcome was eGFR < 30 ml/min/1.73 m2 or death.

RESULTS

Patients had high anti-FH titers 5670 (2177-13,545) AU/ml, relapsing course (42.1%), and adverse outcomes (19.6%). Variants, chiefly of unknown significance, were found in 7 (6.5%; 95% CI 3.1-13.2%); a pathogenic variant was found in one patient. Homozygous deletion of CFHR1 was present in 91.6% compared to 9.8% in 184 healthy controls. Plasma exchanges and immunosuppression showed a trend of improving outcomes, independent of genetic defects (HR 0.32; P = 0.070). Meta-analysis of 18 studies (384 patients) showed that the pooled prevalence of pathogenic and likely pathogenic variants was 3% (95% CI 0-8%). Of 37 total variants in the meta-analysis, 7 (18.9%) each were pathogenic and likely pathogenic; others were variants of unknown significance.

CONCLUSIONS

Significant variants in complement regulatory genes are rare in patients with anti-FH-associated aHUS. Irrespective of genetic defects, plasma exchanges and immunosuppression showed a statistical trend to improved outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.

Short-term safety and efficacy of escalating doses of atorvastatin for dyslipidemia in children with predialysis chronic kidney disease stage 2-5

BACKGROUND

Dyslipidemia is a potentially modifiable risk factor in patients with chronic kidney disease (CKD). Information on the safety and efficacy of statins in pediatric CKD is limited.

METHODS

Patients with CKD stage 2-5 and aged 5-18 years with low-density lipoprotein cholesterol (LDL-C) > 130 mg/dL and/or non-high-density lipoprotein cholesterol (non-HDL-C) > 145 mg/dL were enrolled from September 2019 to February 2021. All patients were administered atorvastatin 10 mg/day, which was escalated to 20 mg/day if LDL-C remained > 100 mg/dL and/or non-HDL-C > 120 mg/dL at 12 weeks. Proportion of patients achieving target lipid levels (LDL-C ≤ 100 mg/dL and non-HDL-C ≤ 120 mg/dL) and adverse events were assessed at 24 weeks.

RESULTS

Of 31 patients enrolled, target lipid levels were achieved in 45.2% (95% CI 27.8-63.7%) at 24 weeks; 22 patients required dose escalation to 20 mg at 12 weeks. There was no difference in median lipid level reduction with 10 (n = 9) versus 20 mg/day (n = 22, P = 0.3). Higher baseline LDL-C (OR 1.06, 95% CI 1.00-1.11) and older age (OR 36.5, 95% CI 2.57-519.14) were independent predictors of failure to achieve target lipid levels with 10 mg/day atorvastatin. None had persistent rise in AST/ALT > 3 times upper normal limit (UNL) or CPK > 10 times UNL. No differences were noted in adverse events due to atorvastatin 10 or 20 mg/day.

CONCLUSION

Atorvastatin (10-20 mg/day) administered for 24 weeks was safe and effectively reduced LDL-C and non-HDL-C in children with CKD stages 2-5. Patients with higher baseline LDL-C required higher doses to achieve the target. A higher resolution version of the Graphical abstract is available as Supplementary information.

Genome profiling of uropathogenic E. coli from strictly defined community-acquired UTI in paediatric patients: a multicentric study

BACKGROUND

Urinary tract infection (UTI) in children is a common bacterial infection. The emergence of extended-spectrum beta-lactamases (ESBLs) poses a major challenge against the treatment of uropathogens. We aimed to characterize the E. coli isolates recovered from children with UTI for their resistance profile and circulating sequence types (ST).

METHODS

Children (> 1.5-18 years of age) from different community health centres of India with symptoms of UTI were enrolled. Isolates causing significant bacteriuria were identified by Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) and tested for antimicrobial susceptibility by the automated system, VITEK-2 (Biomeriux, Durhum, US). Nineteen E. coli isolates (15 ESBL positive and 4 ESBL negative) were sequenced in Oxford Nanopore platform followed by core-genome phylogeny, accessory genome cluster analysis, identification of sequence types, mobile genetic elements, genetic antimicrobial resistance markers. The correlation between detection of antimicrobial resistance genes with phenotypic resistance profiles was also investigated.

RESULTS

Eleven percent of children had significant bacteriuria [male:female-1:1, > 50% were 11-18 years of age group]. E. coli was predominant (86%) followed by K. pneumoniae (11%). Susceptibility of E. coli was highest against fosfomycin (100%) followed by carbapenems (90.7%) and nitrofurantoin (88.8%). ST131 (15.8%) and ST167 (10.5%) found as high-risk clones with the presence of plasmid [IncFIB (63.1%), IncFIA (52.6%)], and composite transposon [Tn2680 (46.6%)] in many isolates. Few isolates coharboured multiple beta-lactamases including blaNDM-5 (33.3%), blaOXA-1 (53.3%), blaCTX-M-15 (60%) and blaTEM-4 (60%).

CONCLUSIONS

This study highlights horizontal transmission of resistance genes and plasmids in paediatric patients at community centers across the nation harbouring multidrug-resistant genes such as blaNDM-5 and blaCTX-M-15 associated with high-risk clones ST131 and ST167. The data is alarming and emphasizes the need for rapid identification of resistance markers to reduce the spread in community. To our knowledge, this is the first multicentric study targeting paediatric UTI patients from the community setting of India.

Feasibility and Efficacy of Sustained Low-Efficiency Dialysis in Critically Ill Children with Severe Acute Kidney Injury

OBJECTIVES

To examine the feasibility, efficacy, and safety of sustained low-efficiency dialysis (SLED) in hemodynamically unstable, critically ill children.

METHODS

Critically ill patients, 1-18 y old with hemodynamic instability (≥ 1 vasoactive drugs) and severe acute kidney injury (AKI) requiring kidney replacement therapy (KRT) in a tertiary care pediatric intensive care unit were prospectively enrolled. Patients weighing ≤ 8 kg or with mean arterial pressure < 5^th percentile despite > 3 vasoactive drugs, were excluded. Patients underwent SLED until hemodynamically stable and off vasoactive drugs, or lack of need for dialysis. The primary outcome was the proportion of patients in whom the first session of SLED was initiated within 12 h of its indication and completed without premature (< 6 h) termination. Efficacy was estimated by ultrafiltration, urea reduction ratio (URR), and equilibrated Kt/V. Other outcomes included: changes in hemodynamic scores, circuit clotting, adverse events, and changes in indices on point-of-care ultrasonography and echocardiography.

RESULTS

Between November 2018 and March 2020, 18 patients with median age 8.6 y and vasopressor dependency index of 83.2, underwent 41 sessions of SLED. In 16 patients, SLED was feasible within 12 h of indication. No session was terminated prematurely. Ultrafiltration achieved was 4.0 ± 2.2 mL/kg/h, while URR was 57.7 ± 16.2% and eKt/V 1.17 ± 0.56. Hemodynamic scores did not change significantly. Asymptomatic hypokalemia was the chief adverse effect. Sessions were associated with a significant improvement in indices on ultrasound and left ventricular function. Fourteen patients died.

CONCLUSIONS

SLED is feasible, safe, and effective in enabling KRT in hemodynamically unstable children with severe AKI.

Clinical Features and Genetic Sequencing of Children with Fanconi-Bickel Syndrome

The present paper reports 10 patients (9 families) with Fanconi-Bickel syndrome managed during 2010-2021. Patients presented with polyuria, polydipsia, hepatomegaly, rickets, and stunting at a median of 5 (3, 7.3) mo; one had transient neonatal diabetes. Glucosuria, generalized aminoaciduria, β₂-microglobinuria, urinary phosphate wasting, and hypercalciuria were present in all patients; 3 patients had nephrocalcinosis. Other metabolic abnormalities included hypertriglyceridemia (n = 5/6), fasting hypoglycemia (n = 5/8), and postprandial hyperglycemia (n = 3/6). Genetic analysis showed 7 homozygous or compound heterozygous variants in SLC2A2. A pathogenic variant c.952G>A, common to 4 patients (3 families), might be a potential hotspot. At a median follow-up of 43 mo, 4 patients died at a median of 25 mo; short stature persisted in all except one patient who showed catch-up growth with uncooked corn-starch diet. The present findings suggest that the Fanconi-Bickel syndrome has a severe phenotype with an unsatisfactory outcome. A high index of suspicion for diagnosis and efforts for facilitation of dietary therapy are necessary.

Antibiotic resistance of uropathogens among the community-dwelling pregnant and nonpregnant female: a step towards antibiotic stewardship

BACKGROUND

Indiscriminate and widespread use of antibiotics has resulted in emergence of many antibiotic-resistant organisms. Antibiotic administration during pregnancy is mostly avoided, unless there is compelling medical condition. We hypothesized that the uropathogens isolated from pregnant women would be more susceptible to antibiotics compared to those isolated from nonpregnant women, thus will be helpful in formulating separate empiric guideline for pregnant women based on the resistance pattern.

METHODS

This was a prospective cross-sectional study conducted over a period of 2 years in which females with the clinical diagnosis of either cystitis or asymptomatic bacteriuria during pregnancy were included from the community settings. Uropathogen species and their antimicrobial resistance pattern were compared between the pregnant and nonpregnant groups. After accounting for centre-to-centre variation and adjusting for age and socio-economic status, the adjusted odds ratio for antibiotic resistance was calculated and compared between pregnant and nonpregnant women using logistic regression analysis.

RESULTS

A total of 1758 women (pregnant: 43.3%; nonpregnant: 56.6%) were screened in the study over a period of 2 years, out of which 9.3% (163/1758) were having significant bacteriuria. Escherichia coli and Klebsiella pneumoniae were the two commonest uropathogen in both the groups; their prevalence being 83.6% in pregnant women and 85.2% in nonpregnant women, respectively. Resistance against ampicillin, cefixime, cefoxitin, ceftazidime, ceftriaxone and amoxicillin-clavulanic acid were found significantly lower in the pregnant women compared to nonpregnant. After adjusting the age and socio-economic status accounting for centre-to-centre variation, the odds of resistance for cefixime, amoxicillin-clavulanic acid and co-trimoxazole were found lower and statistically significant among the pregnant women group.

CONCLUSIONS

The antimicrobial resistance was significantly higher among the community-dwelling nonpregnant women compared to pregnant women in case of few antibiotics. The study highlighted the need of building local antibiogram that could help to initiate the empirical treatment and thus prevent emergence of antimicrobial resistance.

Metabolic and Genetic Evaluation in Children with Nephrolithiasis

OBJECTIVE

To evaluate metabolic and genetic abnormalities in children with nephrolithiasis attending a referral center in North India.

METHODS

The patients aged 1-18 y old with nephrolithiasis underwent biochemical evaluation and whole-exome sequencing. The authors evaluated for monogenic variants in 56 genes and compared allele frequency of 39 reported polymorphisms between patients and 1739 controls from the GenomeAsia 100 K database.

RESULTS

Fifty-four patients, aged 9.1 ± 3.7 y were included. Stones were bilateral in 42.6%, familial in 33.3%, and recurrent in 25.9%. The most common metabolic abnormalities were hypercalciuria (35.2%), hyperoxaluria (24.1%), or both (11.1%), while xanthinuria (n = 3), cystinuria (n = 1), and hyperuricosuria (n = 1) were rare. Exome sequencing identified an etiology in 6 (11.1%) patients with pathogenic/likely pathogenic causative variants. Three variants in MOCOS and one in ATP7B were pathogenic; likely pathogenic variants included MOCOS (n = 2), AGXT, and SLC7A9 (n = 1, each). Causality was not attributed to two SLC34A1 likely pathogenic variants, due to lack of matching phenotype and dominant family history. Compared to controls, allele frequency of the polymorphism TRPV5 rs4252402 was significantly higher in familial stone disease (allele frequency 0.47 versus 0.53; OR 3.2, p = 0.0001).

CONCLUSION

The chief metabolic abnormalities were hypercalciuria and hyperoxaluria. A monogenic etiology was identified in 11% with pathogenic or likely pathogenic variants using a gene panel for nephrolithiasis. Heterozygous missense variants in the sodium-phosphate cotransporter SLC34A1 were common and required evaluation for attributing pathogenicity. Rare polymorphisms in TRPV5 might increase the risk of familial stones. These findings suggest that a combination of metabolic and genetic evaluation is useful for determining the etiology of nephrolithiasis.

Sequential rituximab therapy sustains remission of nephrotic syndrome but carries high risk of adverse effects

BACKGROUND

Sequential rituximab (RTX) administration has emerged as an important strategy to sustain remission of disease in patients with difficult-to-treat nephrotic syndrome.

METHODS

We report the efficacy and safety of sequential therapy with two or more courses of intravenous RTX in 250 patients with difficult-to-treat steroid dependence (n = 127) and calcineurin inhibitor (CNI)-dependent or CNI-refractory steroid resistance (n = 123) managed at one center during 2015-2021. Subsets of patients were cross-sectionally tested for hypogammaglobulinemia, seroprotection against and hyporesponsiveness to vaccines for hepatitis B and tetanus, BK/JC viruria and human antichimeric antibodies (HACAs).

RESULTS

Sequential RTX therapy, initiated at a median of 10 years [interquartile range (IQR) 7.3-14.4], was administered for 1.8 courses/person-year [95% confidence interval (CI) 1.7-2.0] over 2.0 years (95% CI 1.2-3.0). Therapy was associated with postponement of relapses by a median of 3 years in patients with steroid-sensitive disease and 2 years in those with steroid resistance. Relapses were reduced by a mean of 2.0 relapses/person-year (95% CI 1.8-2.2), enabling a reduction in prednisolone dose to 0.04 mg/kg/day (95% CI 0.01-0.11) and withdrawal of additional immunosuppression in 154 (62%) patients. RTX-associated adverse events, occurring at 0.20 events/person-year (95% CI 0.17-0.23), were chiefly comprised of infusion reactions (n = 108) and infections (n = 46); serious adverse events were observed in 10.8% patients, at 0.03 events/person-year (95% CI 0.02-0.05). Hypogammaglobulinemia was observed in 35% of 177 patients and was moderate to severe in 8.5% of cases. Rates of seroprotection at baseline and response following vaccination were lower for hepatitis B [1.9% and 29.4% (n = 52)] than tetanus [65.5% and 34.5% (n = 58)]. BK/JC viruria, without viremia, was observed in 7.3% of 109 cases. A total of 19 of 107 patients (17.8%) had HACAs, which were associated with B cell nondepletion and serum sickness. Age at therapy of <9-10 years was associated with a risk of early relapse, treatment failure and hypogammaglobulinemia following RTX therapy.

CONCLUSIONS

Sequential therapy with RTX effectively reduces relapses in patients with difficult-to-treat steroid- and/or CNI-dependent or CNI-refractory nephrotic syndrome. Therapy is associated with high rates of hypogammaglobulinemia and infusion reactions.

Efficacy and Safety of Combination Therapy with Tolvaptan and Furosemide in Children with Nephrotic Syndrome and Refractory Edema: A Prospective Interventional Study

OBJECTIVE

Severe edema in children with nephrotic syndrome is often refractory to conventional diuretics. Tolvaptan has been used satisfactorily for managing edema in patients with heart failure and cirrhosis. The safety and efficacy of combination therapy with oral tolvaptan and intravenous (IV) furosemide was assessed in patients with furosemide refractory edema.

METHODS

Patients, aged 5-18 y with nephrotic syndrome and severe edema, were screened for eligibility. After excluding hypovolemia, patients received IV furosemide (3-4 mg/kg/d) for 48 h. Those refractory to IV furosemide (weight loss < 3%) received tolvaptan (0.5-1 mg/kg once daily) and IV furosemide for the next 48 h. Parameters were compared between 48 h of furosemide alone and combination therapy.

RESULTS

A total of 24 patients (18 boys) with mean age of 8.0 ± 3.0 y were enrolled. Urine volume significantly increased with combination therapy as compared to furosemide therapy (mean difference: 1.2 mL/kg/h; 95% CI: 0.8-1.65 mL/kg/h) (p < 0.001). Compared to therapy with furosemide alone, combination therapy resulted in significant reduction in body weight from 26.9 ± 10.3 kg to 24.8 ± 9.7 kg (p < 0.001). Estimated glomerular filtration rate did not change (p = 0.81) but serum sodium increased from 135.7 ± 3.3 mEq/L to 140.4 ± 4.8 mEq/L (p < 0.001) with combination therapy; 2 patients showed asymptomatic hypernatremia.

CONCLUSION

The combination of oral tolvaptan and IV furosemide is effective in augmenting diuresis and reducing weight in patients with furosemide refractory edema but requires monitoring of electrolytes and volume status.

Genetic and clinical profile of patients with hypophosphatemic rickets

Nutritional vitamin D deficiency is the most frequent cause of rickets followed by genetic causes, that include entities classic hypophosphatemic rickets (FGF23 related), Dent disease, Fanconi syndrome, renal tubular acidosis, and vitamin D dependent rickets. Hypophosphatemia is a feature in all these forms. The diagnosis relies on a combination of clinical, biochemical and radiological features, but genetic testing is required to confirm the diagnosis. Between May 2015 and July 2019, we screened 66 patients with hypophosphatemic rickets by whole exome sequencing (WES) referred to this center in addition to measurement of intact fibroblast growth factor 23 (FGF23) levels in serum. WES revealed 36 pathogenic and 28 likely pathogenic variants in 16 different genes (PHEX, FGF23, DMP1, ENPP1, CLCN5, CTNS, SLC2A2, GATM, SLC34A1, EHHADH, SLC4A1, ATP6V1B1, ATP6V0A4, CYP27B1, VDR and FGFR1) in 63 patients which helped differentiate various forms of hypophosphatemic rickets. Intact serum FGF23 levels were significantly higher in patients with variations in PHEX, FGF23, DMP1 or ENPP1 genes. The chief genetic causes of rickets were classic hypophosphatemic rickets with elevated FGF23 levels, distal renal tubular acidosis, and vitamin D dependent rickets. Based on the present results, we propose a customized gene panel for targeted exome sequencing, which will be useful for confirming the diagnosis in most patients with hypophosphatemic rickets.

Virulence gene mutations as a differentiator of clinical phenotypes: insights from community-acquired uropathogenic Escherichia coli

Uropathogenic Escherichia coli (UPEC) remains an important cause of urinary tract infection during pregnancy. Multiple molecular virulence determinants and antibiotic resistant genes facilitate its pathogenesis and virulence phenotype. Hence it is hypothesized that there will be considerable variation in genes among the isolates from symptomatic as well as asymptomatic bacteriuria (ABU) during pregnancy. The aim of this study was to decipher the genetic variation among the two phenotypes. Six different UPEC isolates collected from urine specimens of consecutive pregnant females (five, symptomatic bacteriuria and one, ABU) were tested for their growth kinetics, and biofilm formation. A total of 87 virulence determinants and 56 antibiotic resistance genes were investigated using whole-genome sequencing, to identify putative drives of virulence phenotype. In this analysis, we identified eight different types of fully functional toxin antitoxin (TA) systems [HipAB, YefM-YoeB, YeeU-YeeV (CbtA), YhaV-PrlF, ChpBS, HigAB, YgiUT and HicAB] in the isolates from symptomatic bacteriuria; whereas partially functional TA system with mutations were observed in the asymptomatic one. Isolates of both the groups showed equivalent growth characteristics and biofilm-formation ability. Genes for an iron transport system (Efe UOB system, Fhu system except FhuA) were observed functional among all symptomatic and asymptomatic isolates, however functional mutations were observed in the latter group. Gene YidE was observed predominantly associated with the biofilm formation along with few other genes (BssR, BssS, YjgK, etc.). This study outlines putative critical relevance of specific variations in the genes for the TA system, biofilm formation, cell adhesion and colonization among UPEC isolates from symptomatic and asymptomatic bacteriuria among pregnant women. Further functional genomic study in the same cohort is warranted to establish the pathogenic role of these genes.

Prevalence and resistance pattern of uropathogens from community settings of different regions: an experience from India

Introduction

Urinary tract infection (UTI) is one of the most common infections in clinical practice worldwide in both healthcare and community settings causing significant morbidity and mortality. It is one of the major conditions at the community level treated empirically and regarded as a potential cause of emergence of antimicrobial resistance (AMR). Limited information is available regarding community-acquired UTI (CA-UTI) from India.

Methodology

This is a first of its kind, multicentric-cross-sectional study at the community level targeting patients attending the out-patient department (OPD) of the community health centre (CHC) from four geographical regions (North, South, West and East) of India. The study had been designed to determine the epidemiology, antibiogram profile and identification of extended-spectrum beta-lactamase (ESBL) producer and carbapenem resistant (CR) uropathogens. Samples were collected prospectively from UTI suspected patients coming at CHC and processed at the tertiary healthcare centres using a common standard operating procedure. Clinical history of all the patients exhibiting significant bacteriuria was collected and data was analysed.

Result

Overall, 250 out of a total of 2459 (10.1 %) urine samples were positive for bacteria with significant bacteriuria (adult: paediatrics, 6.7 : 1). Females were predominantly affected (male: female, 1 : 2.9). History of recent episode of UTI was observed as the commonest risk factor followed by diabetes mellitus. Altogether, 86 % of total cases were caused by Escherichia coli (68 %) and Klebsiella pneumoniae (17.6 %) together. Among the commonly used oral antibiotics for the Gram-negative bacilli (GNB), the highest resistance was observed against beta-lactams, first- and second-generation cephalosporins, fluoroquinolones and co-trimoxazole. Overall, the prevalence of ESBL producer and CR isolates were 44.8, and 4.3 %, respectively. However, the ESBL production, CR and nitrofurantoin resistance among the uropathogenic E. coli (UPEC) isolates was 52.8, 5.1 and 14 %, respectively. No resistance was found against fosfomycin among the UPEC isolates.

Conclusion

The current study highlights the increasing incidence of AMR among uropathogens at the community-settings of India. A significant percentage of ESBL producers among the isolated UPEC and K. pneumoniae were observed. The currently available evidence supports the clinical recommendation of fosfomycin and nitrofurantoin for empiric therapy in CA-UTI in India.

Anti-factor H antibody associated hemolytic uremic syndrome following SARS-CoV-2 infection

BACKGROUND

The pathogenesis of autoantibody generation in anti-factor H (FH) antibody associated atypical hemolytic uremic syndrome (aHUS) is unknown and is perhaps triggered by an infectious or environmental agent. We observed an unusual increase of patients with anti-FH antibody associated aHUS coinciding with the second pandemic wave in New Delhi and suspected that SARS-CoV-2 infection might be a potential trigger.

METHODS

We screened for SARS-CoV-2 infection using reverse transcriptase polymerase chain reaction (RT-PCR) and serology in 13 consecutive patients with anti-FH antibody associated aHUS during the past year in New Delhi.

RESULTS

We report 5 patients, 4-13 years old, who presented with a febrile illness without respiratory symptoms during the second pandemic wave. Of these, 3 patients presented with a relapse 25-85 months following the initial episode of aHUS. SARS-CoV-2 was detected by RT-PCR in 1 patient and by serology in 4 patients (median titer 47.1 cut-off index). Patients had high titers of anti-FH antibodies (median 2,300 AU/ml). Genetic studies, done in 3 of the 5 patients, showed homozygous CFHR1 deletion without other significant genetic abnormalities. Specific management comprised plasma exchanges and oral prednisolone, combined with either cyclophosphamide or mycophenolate mofetil. At median follow-up of 3.3 months, the estimated glomerular filtration rate in 4 patients ranged from 62 to 110 ml/min/1.73 m²; one patient was dialysis-dependent.

CONCLUSION

Increased vigilance is required during the pandemic, especially in patients with anti-FH associated aHUS, who might relapse despite quiescent disease for a prolonged period. A higher resolution version of the Graphical abstract is available as Supplementary information.

SARS-CoV-2 infection in children with chronic kidney disease

BACKGROUND

Information on the course of SARS-CoV-2 infection in children with chronic kidney disease (CKD) is limited.

METHODS

We retrospectively reviewed the presentation and outcomes of SARS-CoV-2 infection in patients with CKD followed at any of the four pediatric nephrology centers in New Delhi from April 2020 to June 2021. Outcomes, including cardiopulmonary and renal complications, were reported in relation to underlying disease category and illness severity at presentation.

RESULTS

Underlying illness in 88 patients included nephrotic syndrome (50%), other CKD stages 1-4 (18.2%), CKD 5D (17%), and CKD 5T (14.8%). Thirty-two of 61 patients with symptomatic COVID-19 and 9/27 asymptomatic patients were admitted for median 10 (interquartile range 7-15) days. Seventeen (19.3%) patients developed moderate or severe COVID-19. Systemic complications, observed in 30 (34.1%), included acute kidney injury (AKI, 34.2%), COVID-19 pneumonia (15.9%), unrelated pulmonary disease (2.3%), and shock (4.5%). Nineteen (21.6%) had severe complications (AKI stage 2-3, encephalopathy, respiratory failure, shock). Eight (11%) of twelve (16.4%) patients with severe AKI required dialysis. Three (3.4%) patients, two with steroid-resistant nephrotic syndrome in relapse and one with CKD 1-4, died due to respiratory failure. Univariate logistic regression indicated that patients presenting with nephrotic syndrome in relapse or moderate to severe COVID-19 were at risk of AKI (respective odds ratio, 95%CI: 3.62, 1.01-12.99; 4.58, 1.06-19.86) and/or severe complications (respective odds ratio, 95%CI: 5.92, 1.99-17.66; 61.2, 6.99-536.01).

CONCLUSIONS

Children with CKD presenting with moderate-to-severe COVID-19 or in nephrotic syndrome relapse are at risk of severe complications, including severe AKI and mortality. A higher resolution version of the Graphical abstract is available as Supplementary information.

Non-antibiotic interventions for prevention of urinary tract infections in children: a systematic review and meta-analysis of randomized controlled trials

A considerable proportion of children experience a recurrence of urinary tract infection (UTI) following the first episode. While low-dose antibiotic prophylaxis has been the mainstay for the prevention of UTI, recent evidence raised concerns over their efficacy and safety. Hence, we aim to systematically synthesize evidence on the efficacy and safety of non-antibiotic prophylactic interventions for UTI. Using keywords related to study population (children) and intervention (non-antibiotic), we searched CENTRAL, Embase, PubMed, and Web of Science for randomized controlled trials (RCTs) published until August 2020. RCTs comparing any non-antibiotic interventions with placebo/antibiotics for prevention of UTIs in children were considered eligible. We used a random-effect model to provide pooled estimates. Sixteen trials evaluating 1426 participants were included. Cranberry was as effective as antibiotic prophylaxis (RR: 0.92; 95% CI: 0.56-1.50) but better than placebo/no therapy (RR: 0.48; 95% CI: 0.28-0.80) in reducing UTI recurrence. Probiotic therapy was more effective in reducing UTI recurrence (RR: 0.52; 95% CI: 0.29-0.94) when compared with placebo. While probiotic therapy was not better than antibiotics prophylaxis in preventing UTI (RR: 0.82; 95% CI: 0.56-1.21), they have a lower risk of antibiotic resistance (RR: 0.38; 95% CI: 0.21-0.69).Conclusion: Cranberry products and probiotics are the two non-antibiotic interventions that have been chiefly evaluated, reduce the risk of UTI recurrence when compared with placebo in children with a normal urinary tract. The findings from this systematic review suggest that while cranberry and probiotics may be used, there is a definite need to identify better and more acceptable non-antibiotic interventions. What is Known: • Efficacy of the low-dose antibiotic is controversial in preventing UTI and it is associated with increase in the risk of antimicrobial resistance. • Non-antibiotic interventions such as cranberry products are effective in preventing UTI recurrence in adults. What is New: • Cranberry products are effective in reducing the recurrence of UTI in children with normal urinary tract. • Low-quality evidence suggests that probiotics can be a potential prophylactic measure to reduce recurrence of UTI in the pediatric population.

Consensus Guidelines on Management of Steroid-Resistant Nephrotic Syndrome

JUSTIFICATION

The management of steroid resistant nephrotic syndrome (SRNS) is challenging. These guidelines update existing 2009 Indian Society of Pediatric Nephrology recommendations on its management.

OBJECTIVE

To frame revised guidelines on diagnosis and evaluation, treatment and follow up, and supportive care of patients with the illness.

PROCESS

The guidelines combine evidence-based recommendations and expert opinion. Formulation of key questions was followed by systematic review of literature, evaluation of evidence by experts and two face-to-face meetings.

RECOMMENDATIONS

Fourteen statements provide updated advice for managing steroid resistance, and underscore the importance of estimating proteinuria and baseline kidney function, and the need for kidney biopsy and genetic screening. Calcineurin inhibitors are recommended as most effective in inducing remission of proteinuria, the chief factor associated with long-term renal survival. Advice on managing allograft recurrence, congenital nephrotic syndrome, and monitoring and supportive care, including transition of care, are described. This revised practice guideline is intended to improve management and patient outcomes, and provide direction for future research.

Next-Generation Sequencing for Congenital Nephrotic Syndrome: A Multi-Center Cross-Sectional Study from India

OBJECTIVE

Information on etiology of congenital nephrotic syndrome in non-Caucasian populations is limited. This study aimed to determine the genetic basis of congenital nephrotic syndrome in Indian patients.

METHODS

In this observational, cross-sectional study, whole exome sequencing was performed on samples from all children diagnosed with congenital nephrotic syndrome, presenting at centers collaborating in a nationwide registry and biorepository. Analysis was targeted to focus on reported or novel, pathogenic or likely pathogenic variants in 89 genes implicated in etiology of nephrotic syndrome. Sanger sequencing was used to confirm disease-causing variants in patients and allelic segregation of compound heterozygous variants in samples from parents. Inheritance of a shared haplotype was analyzed among ten individuals carrying the most common variant.

RESULTS

During 2017-2019, 34 patients with congenital nephrotic syndrome were screened. Consanguinity and similar illness in siblings were reported in eleven patients each. Homozygous or compound heterozygous, pathogenic or likely pathogenic variants were found in NPHS1 in 24 cases, including two novel variants. One patient each had homozygous pathogenic or likely pathogenic known or novel variant in NPHS2, PLCE1, OSGEP and LAMB2 genes. Patients with OSGEP and LAMB2 mutations had phenotype typical of Galloway Mowat and Pierson syndromes, respectively. Three variants in NPHS1 were common to 16 individuals. One reported variant in exon 19 (c.2600G>A; p.Gly867Asp) appears to share a common founder.

CONCLUSIONS

A genetic cause was determined for 82.4% patients with congenital nephrotic syndrome. Variants in NPHS1 are most common in Indian patients and founder mutations might be present.

Phenotypic variability in distal acidification defects associated with WDR72 mutations

BACKGROUND

Distal renal tubular acidosis (RTA) is typically caused by defects in ATP6V0A4, ATP6V1B1, and SLC4A1, accounting for 60-80% of patients. Genes recently implicated include FOXI1, ATP6V1C2, and WDR72, of which WDR72 is associated with dental enamel defects.

METHODS

We describe 4 patients, from three unrelated consanguineous families, with RTA and amelogenesis imperfecta. Distal tubular acidification was evaluated by furosemide-fludrocortisone test, urine-to-blood PCO2 gradient and fractional excretion of bicarbonate. Exome sequencing was performed using a panel of genes implicated in human disease.

RESULTS

Patients had polyuria, hypokalemia, hypercalciuria, and nephrocalcinosis, but metabolic acidosis varied in severity. Although all patients acidified urine to pH < 5.3 during furosemide-fludrocortisone test, urine-to-blood PCO₂ gradient was < 20 mmHg during bicarbonate loading. All patients had transient proximal tubular dysfunction with urinary losses of phosphate and beta-2-microglobulin, and generalized aminoaciduria. Homozygous pathogenic truncating variants in WDR72 was detected in all probands.

CONCLUSION

Patients with WDR72 mutations show mild rate-dependent distal RTA with variable metabolic acidosis, and intact ability to acidify the urine on provocative testing. Concomitant proximal tubular dysfunction may be present. Mutations in WDR72 should be considered in patients with suspected distal RTA, especially if associated with dental defects.

Short-Duration Prednisolone in Children with Nephrotic Syndrome Relapse: A Noninferiority Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

In children with nephrotic syndrome, steroids are the cornerstone of therapy for relapse. The adequate duration and dosage of steroids, however, have not been an active area of research, especially in children with infrequently relapsing nephrotic syndrome. This study investigated the efficacy of an abbreviated regimen for treatment of a relapse in this population.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a single-center, open-label, randomized controlled trial, we evaluated the efficacy of prednisolone as a "short regimen" (40 mg/m² on alternate days for 2 weeks) compared with "standard regimen" (40 mg/m² on alternate days for 4 weeks) for children aged 1-16 years who achieved remission of a relapse. The primary outcome was the proportion of children developing frequent relapses or steroid dependence at 12 months.

RESULTS

A total of 117 patients were enrolled and randomized to short (55) or standard (62) regimen. Fourteen (24%) patients in standard regimen and 12 (23%) in short regimen developed frequent relapses or steroid dependence over a period of 1 year (risk difference, -1%; 95% confidence interval, -15 to 16; P=0.90). A large 95% confidence interval crossed the proposed noninferiority margin. In a time to event analysis, there was no significant difference in the proportion of children developing frequent relapses or steroid dependence and time to outcome between the two groups (hazard ratio, 1.01; 95% confidence interval, 0.83 to 1.23; P=0.98). Time to relapse, relapse rate, and steroid-related adverse events were similar in both groups. Cumulative steroid exposure was significantly lower in the short regimen (risk difference, -541 mg/m²; 95% confidence interval, -917 to -164 mg/m²; P<0.001).

CONCLUSIONS

In children with infrequently relapsing nephrotic syndrome, a short steroid treatment for relapse resulted in a similar proportion of patients developing frequent relapses or steroid dependence; however, noninferiority of a short regimen was not established.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

CTRI/2015/11/006345.

Dyslipidemia and cardiovascular health in childhood nephrotic syndrome

Children with steroid-resistant nephrotic syndrome (SRNS) are exposed to multiple cardiovascular risk factors predisposing them to accelerated atherosclerosis. This risk is negligible in steroid-sensitive nephrotic syndrome, but a substantial proportion of children with SRNS progress to chronic kidney disease, exacerbating the already existing cardiovascular risk. While dyslipidemia is an established modifiable risk factor for cardiovascular disease in adults with NS, it is uncertain to what extent analogous risks exist for children. There is increasing evidence of accelerated atherosclerosis in children with persistently high lipid levels, especially in refractory NS. Abnormalities of lipid metabolism in NS include hypertriglyceridemia and hypercholesterolemia due to elevated apolipoprotein B-containing lipoproteins, decreased lipoprotein lipase and hepatic lipase activity, increased hepatic PCSK9 levels, and reduced hepatic uptake of high-density lipoprotein. Existing guidelines for the management of dyslipidemia in children may be adapted to target lower lipid levels in children with NS, but they will most likely require both lifestyle modifications and pharmacological therapy. While there is a lack of data from randomized controlled trials in children with NS demonstrating the benefit of lipid-lowering drugs, therapies including statins, bile acid sequestrants, fibrates, ezetimibe, and LDL apheresis have all been suggested and/or utilized. However, concerns with the use of lipid-lowering drugs in children include unclear side effect profiles and unknown long-term impacts on neurological development and puberty. The recent introduction of anti-PCSK9 monoclonal antibodies and other therapies targeted to the molecular mechanisms of lipid transport disrupted in NS holds promise for the future treatment of dyslipidemia in NS.

Managing Children With Renal Diseases During the COVID-19 Pandemic

The coronavirus outbreak is a rapidly evolving pandemic, placing unprecedented strain on health-care systems. COVID-19 presents challenges for management of children with renal diseases, especially those receiving long-term immunosuppressive medications, including renal transplant recipients and those with chronic kidney disease and acute kidney injury requiring dialysis. Our preparedness for managing this vulnerable group of children is the need of the hour. The purpose of this article is to provide guidance to caregivers and health care personnel involved in management of children with renal diseases and to ensure patient well-being, while protecting staff from infection.

Isolated nephrocalcinosis due to compound heterozygous mutations in renal outer medullary potassium channel

Identification of a monogenic etiology is possible in a proportion of patients with childhood-onset nephrolithiasis or nephrocalcinosis. Bartter syndrome (BS), a hereditary tubulopathy characterized by polyuria, hypokalemic alkalosis and growth retardation that rarely presents with isolated nephrocalcinosis. Patients with defect in renal outer medullary potassium channel, encoded by the KCNJ1 gene causing BS type 2, typically present during the neonatal period. We describe a 14-year-old girl with mild late-onset BS type 2 with reported pathogenic compound heterozygous variations in exon 2 of KCNJ1 (c.146G > A and c.657C > G). This patient presented with isolated medullary nephrocalcinosis due to hypercalciuria; absence of hypokalemia and metabolic alkalosis was unique. This case highlights the importance of screening the KCNJ1 gene in patients with hypercalciuria and nephrocalcinosis, even in older children.

Prevalence of Bladder and Bowel Dysfunction in Toilet-Trained Children With Urinary Tract Infection and/or Primary Vesicoureteral Reflux: A Systematic Review and Meta-Analysis

Introduction: Urinary tract infection (UTI) in children leads to renal scarring in 10-15% of patients. Urinary tract anomalies and bladder and bowel dysfunction (BBD) are documented risk factors for recurrent UTIs. Estimates of baseline prevalence of BBD in children with UTI will help the clinician in the management strategy. Hence, a systematic review and meta-analysis was conducted to estimate the pooled prevalence of BBD. Methods: MEDLINE, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) databases were searched for articles related to UTI, primary vesicoureteral reflux (VUR), and BBD. We included studies that provided prevalence of BBD in toilet-trained patients aged 1-18 years with UTI and/or VUR. BBD was defined based on clinical history or questionnaire or urodynamic studies. Two authors independently reviewed, assessed, and abstracted data from studies. Pooled prevalence was calculated based on a random effects model. Results: Forty-three studies fulfilling the eligibility criteria were selected from a total of 1,731 studies. Among patients presenting with UTI without primary VUR, pooled prevalence of BBD was 41% (95% CI: 26-55; nine studies, 920 patients, I ² = 96.0%), whereas its prevalence in patients with primary VUR was 49% (43-56; 30 studies, 5,060 patients, I ² = 96.0%). Weighting by the study design and quality did not affect the prevalence. In patients with primary VUR, prevalence of BBD was higher in females (53%; 42-65) than in males (44%; 15-73). In studies where urodynamic study was used for the diagnosis of BBD, prevalence was 63%. The presence of BBD in patients with primary VUR increased risk of recurrent UTIs [relative risk (RR): 2.1; 1.7-2.5]. In five studies that reported separate data on constipation, pooled prevalence of constipation was 27% (16-37). Conclusion: Almost half of the patients with primary VUR have BBD, and its presence increases the risk of recurrent UTIs. Trends of high BBD prevalence were also observed in patients presenting with UTI without VUR. These prevalence estimates suggest that all toilet-trained children presenting with UTI with or without VUR should be assessed for BBD, which will help in their further management.

Hemolytic uremic syndrome in a developing country: Consensus guidelines

BACKGROUND

Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country.

METHODS

Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017.

RESULTS

An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted.

CONCLUSIONS

Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.

Membrane-filtration based plasma exchanges for atypical hemolytic uremic syndrome: Audit of efficacy and safety

BACKGROUND

While complement blockade with eculizumab is recommended as first-line therapy of atypical hemolytic uremic syndrome (aHUS), plasma exchanges (PEX) remain the chief option for anti-factor H (FH) antibody associated disease and when access to eculizumab is limited.

METHODS

We reviewed adverse events (AEs) and adverse outcomes (eGFR <30 mL/min/1.73 m² or death), in all patients with aHUS managed with membrane-filtration based PEX at one tertiary care center over 5.5 years.

RESULTS

During January 2013 to June 2018, 109 patients with aHUS (74 with antibodies to FH), aged median (range) 7.6 (0.5-18) year weighing 22.1 (6-90) kg, underwent 2024 sessions of PEX. AE, in 12.1% patients, were usually self-limiting and included chills (5.5%), vomiting/abdominal pain (3.3%), hypotension (1.6%), urticaria (1.5%), seizures (0.2%), hypocalcemia (0.2%), and hemorrhage (0.1%); plasma hypersensitivity and severe reactions were rare. Rate of catheter-related infections was 1.45/1000 catheter-days. Filter reuse (OR 1.69; 95% CI 1.26-2.26; P < .001) and >20 sessions of PEX/patient (OR 1.99; 95% CI 1.27-3.10; P = .002) were independently associated with adverse events; infusion of IV calcium gluconate during PEX was protective (OR 0.26; 95% CI 0.16-0.43; P < .001). Hematological remission was achieved in 96.3% patients after 6 (5-8) PEX sessions; 80.8% and 89.6% patients were dialysis independent by one and 3 months, respectively.

CONCLUSIONS

PEX is safe and associated with satisfactory short-term outcomes in children with aHUS. Prolonged PEX and filter-reuse are associated with complications.

Clinical and Immunological Profile of Anti-factor H Antibody Associated Atypical Hemolytic Uremic Syndrome: A Nationwide Database

Background: Atypical hemolytic uremic syndrome (aHUS), an important cause of acute kidney injury (AKI), is characterized by dysregulation of the alternative complement pathway. Autoantibodies to factor H (FH), a chief regulator of this pathway, account for a distinct subgroup. While high anti-FH titers predict relapse, they do not correlate well with disease activity and their functional characterization is required.

Methods: Of 781 patients <18-year-old of aHUS in the nationwide database from 2007 to 2018, 436 (55.8%) had anti-FH antibodies. Clinical features and outcome of patients managed in the last 6-year (n = 317) were compared to before (n = 119). In plasma samples of 44 patients, levels of serial circulating FH immune complexes (CIC), free FH, soluble terminal complement complex (sC5b-9), sheep red blood cell (SRBC) lysis and epitope specificity (n = 8) were examined. Functional renal reserve, ambulatory hypertension, left ventricular hypertrophy (LVH), and proteinuria were evaluated in a subset.

Results: Patients presented with markedly elevated anti-FH titers (10,633.2 ± 998.5 AU/ml). Management varied by center, comprising plasma exchange (PEX; 77.5%) and immunosuppression (73.9%). Patients managed in the last 6-year showed better renal survival at mean 28.5 ± 27.3 months (log rank P = 0.022). Mean anti-FH titers stayed 700–1,164 AU/ml during prolonged follow-up, correlating with CIC. Patients with relapse had lower free-FH during remission [Generalized estimating equations (GEE), P = 0.001]; anti-FH levels ≥1,330 AU/ml and free FH ≤440 mg/l predicted relapse (hazards ratio, HR 6.3; P = 0.018). Epitope specificity was similar during onset, remission and relapse. Antibody titer ≥8,000 AU/ml (HR 2.23; P = 0.024), time to PEX ≥14 days (HR 2.09; P = 0.071) and PEX for <14 days (HR 2.60; P = 0.017) predicted adverse renal outcomes. Combined PEX and immunosuppression improved long-term outcomes (HR 0.37; P = 0.026); maintenance therapy reduced risk of relapses (HR 0.11; P < 0.001). At 4.4±2.5 year, median renal reserve was 15.9%; severe ambulatory, masked and pre-hypertension were found in 38, 30, and 18%, respectively. Proteinuria and LVH occurred in 58 and 28% patients, respectively.

Conclusion: Prompt recognition and therapy with PEX and immunosuppression, is associated with satisfactory outcomes. Free-FH predicts early relapses in patients with high anti-FH titers. A significant proportion of impaired functional reserve, ambulatory hypertension, proteinuria and LVH highlight the need for vigilant long-term follow-up.

C-Terminal Fibroblast Growth Factor-23 Levels in Non-Nutritional Hypophosphatemic Rickets

Fibroblast growth factor-23 (FGF23) is central to phosphate homeostasis. The author examined if blood levels of FGF23 allow discrimination of classic hypophosphatemic rickets from other causes of non-nutritional rickets with hypophosphatemia. Forty-two children (median age: 102 mo) with non-nutritional rickets and hypophosphatemia were clinically classified as having distal renal tubular acidosis (RTA, n = 12), Fanconi syndrome (n = 8), classic hypophosphatemic rickets (n = 11), vitamin D dependent rickets (n = 7) and Dent disease (n = 4). Median blood FGF23 (measured by C-terminal ELISA) concentrations were similar in all groups (P = 0.24). These levels did not correlate with phosphate, tubular maximum for phosphate, calcium, 25-hydroxyvitamin D, creatinine, and parathormone levels. Patients with distal RTA showed variable degree of proximal tubular dysfunction that resolved following alkali supplements. Blood FGF23 levels did not satisfactorily differentiate classic hypophosphatemic rickets from other causes of hypophosphatemic rickets.

Glomerular C4d Staining Does Not Exclude a C3 Glomerulopathy

Introduction

C4d, an early product in the classical/lectin complement pathway has shown potential in the evaluation of C3 glomerulopathy where its absence would support an alternative pathway abnormality. As autoimmune/genetic complement testing is not readily available to most parts of the world, glomerular C4d staining may serve as a useful additional step toward the diagnosis.

Methods

To test this hypothesis, C4d staining was performed on a large cohort of C3 glomerulopathy. Archival cases from 2011 to 2017 were reviewed and immunohistochemistry for C4d was performed, scored (scale of 0 to 3+), and correlated with the immunofluorescence and ultrastructural findings. Paraffin immunofluorescence was performed in cases of "discordant C4d" to unmask Igs.

Results

Twenty-seven cases of dense deposit disease (DDD) and 14 cases of C3 glomerulonephritis (C3GN) were retrieved. C4d demonstrated a range of staining intensities with negative/traces in only 22% of DDD and 64% of C3GN. Lower-intensity C4d staining (1 to 2+) was mostly concordant with similar amounts of Igs/C1q. Discordant 3+ staining was noted in approximately 50% of cases of DDD and 20% of cases of C3GN. Among them, paraffin immunofluorescence unmasked polyclonal Igs in 2 of 5 cases of DDD and 1 of 3 cases of C3GN.

Conclusion

This observational study suggests that the presence of glomerular C4d should not exclude a C3 glomerulopathy. In lower intensities, it appears to represent overlying classical/lectin pathway activation with concordant Ig/C1q deposits. A subset of cases, however, displays intense and discordant C4d staining, which raises the possibility of an associated lectin pathway abnormality, a potential future area of study.

Posttransplant Lymphoproliferative Disorder: Experience from a Pediatric Nephrology Unit in North India

Posttransplant lymphoproliferative disorder (PTLD) is reported in 1%–3% among pediatric renal allograft recipients. We report the experience of PTLD among pediatric renal allograft recipients at a pediatric nephrology center in North India. Four cases of PTLD were identified from among records of 95 pediatric renal allograft recipients over a period of 21 years. Constitutional and localizing symptoms were present in three patients each. The diagnosis was suggested on positron emission tomography in three patients and confirmed by histopathology in all. Sites affected included tonsils, cervical lymph nodes, duodenum, and para-aortic lymph nodes in one patient each. The lymphocytic infiltrate was polymorphic in three patients and monomorphic in one. Immunostaining suggested B-cell origin in all patients. There was evidence of Epstein–Barr virus infection in only one patient. The patients were successfully managed with reduction of immunosuppression (in all), rituximab (in 3), and excision of affected tissue (in 1). Over a follow-up period of 30–88 months, there were no episodes of disease recurrence or allograft rejection, and renal function was preserved.