Nutrition in critically ill children with acute kidney injury on continuous kidney replacement therapy: a 2023 executive summary

OBJECTIVES

Nutrition plays a vital role in the outcome of critical illness in children, particularly those with acute kidney injury. Currently, there are no established guidelines for children with acute kidney injury treated with continuous kidney replacement therapy. Our objective was to create clinical practice points for nutritional assessment and management in critically ill children with acute kidney injury receiving continuous kidney replacement therapy.

METHODS

An electronic search using PubMed and an inclusive academic library search (including MEDLINE, Cochrane, and Embase databases) was conducted to find relevant English-language articles on nutrition therapy for children (<18 y of age) receiving continuous kidney replacement therapy.

RESULTS

The existing literature was reviewed by our work group, comprising pediatric nephrologists and experts in nutrition. The modified Delphi method was then used to develop a total of 45 clinical practice points. The best methods for nutritional assessment are discussed. Indirect calorimetry is the most reliable method of predicting resting energy expenditure in children on continuous kidney replacement therapy. Schofield equations can be used when indirect calorimetry is not available. The non-intentional calories contributed by continuous kidney replacement therapy should also be accounted for during caloric dosing. Protein supplementation should be increased to account for the proteins, peptides, and amino acids lost with continuous kidney replacement therapy.

CONCLUSIONS

Clinical practice points are provided on nutrition assessment, determining energy needs, and nutrient intake in children with acute kidney injury and on continuous kidney replacement therapy based on the existing literature and expert opinions of a multidisciplinary panel.

Low Birth Weight is Associated with More Severe Course of Steroid-Sensitive Nephrotic Syndrome in Children, Multicentric Study

BACKGROUND

Several previous studies have reported a more severe course of nephrotic syndrome in children with low birth weight.

PATIENTS

Cohort of 223 children with idiopathic nephrotic syndrome.

METHODS

We aimed to investigate the association between course of nephrotic syndrome and low birth weight. Data from seven paediatric nephrology centres were used.

RESULTS

Children with low birth weight had 3.84 times higher odds for a more severe course of steroid-sensitive nephrotic syndrome (95% CI 1.20-17.22, P=0.041), and those with low birth weight and remission after 7 days had much higher odds for a more severe course of disease (OR 8.7). Low birth weight children had a longer time to remission (median 12 vs. 10 days, P=0.03). They had a higher need for steroid-sparing agents (OR for the same sex=3.26 [95% CI 1.17-11.62, P=0.039]), and the odds were even higher in females with low birth weight (OR 6.81). There was no evidence of an association either between low birth weight and focal segmental glomerulosclerosis or between low birth weight and steroid-resistant nephrotic syndrome.

DISCUSSION

We conducted the first multicentric study confirming the worse outcomes of children with NS and LBW and we found additional risk factors.

CONCLUSIONS

Low birth weight is associated with a more severe course of steroid-sensitive nephrotic syndrome, while being female and achieving remission after 7 days are additional risk factors.

Nutrition in Critically Ill Children with AKI on Continuous RRT: Consensus Recommendations

BACKGROUND

Nutrition plays a vital role in the outcome of critically ill children, particularly those with AKI. Currently, there are no established guidelines for children with AKI treated with continuous RRT (CRRT). A thorough understanding of the metabolic changes and nutritional challenges in AKI and CRRT is required. Our objective was to create clinical practice points for nutritional assessment and management in critically ill children with AKI receiving CRRT.

METHODS

PubMed, MEDLINE, Cochrane, and Embase databases were searched for articles related to the topic. Expertise of the authors and a consensus of the workgroup were additional sources of data in the article. Available articles on nutrition therapy in pediatric patients receiving CRRT through January 2023.

RESULTS

On the basis of the literature review, the current evidence base was examined by a panel of experts in pediatric nephrology and nutrition. The panel used the literature review as well as their expertise to formulate clinical practice points. The modified Delphi method was used to identify and refine clinical practice points.

CONCLUSIONS

Forty-four clinical practice points are provided on nutrition assessment, determining energy needs, and nutrient intake in children with AKI and on CRRT on the basis of the existing literature and expert opinions of a multidisciplinary panel.

Nephrotic syndrome sera induce different transcriptomes in podocytes based on the steroid response

As the molecular mechanism of nephrotic syndrome remains largely undiscovered, patients continue to be exposed to the pros and cons of uniform glucocorticoid treatment. We explored whether the exposure of in vitro-cultivated podocytes to sera from children with steroid-sensitive or steroid-resistant nephrotic syndrome induces differences in gene expression profiles, which could help to elucidate the pathogenesis of the steroid response. Human immortalized podocytes were cultivated with patient sera for 3 days. After cell lysis, RNA extraction, 3'-mRNA libraries were prepared and sequenced. There were 34 significantly upregulated and 14 downregulated genes (fold difference <0.5 and >2.0, respectively, and false discovery rate-corrected p < 0.05) and 22 significantly upregulated and 6 downregulated pathways (false discovery rate-corrected p < 0.01) in the steroid-sensitive (n = 9) versus steroid-resistant group (n = 4). The observed pathways included upregulated redox reactions, DNA repair, mitosis, protein translation and downregulated cholesterol biosynthesis. Sera from children with nephrotic syndrome induce disease subtype-specific transcriptome changes in human podocytes in vitro. However, further exploration of a larger cohort is needed to verify whether clinically distinct types of nephrotic syndrome or disease activity may be differentiated by specific transcriptomic profiles and whether this information may help to elucidate the pathogenesis of the steroid response.

Fluid management in children with volume depletion

Volume depletion is a common condition and a frequent cause of hospitalization in children. Proper assessment of the patient includes a detailed history and a thorough physical examination. Biochemical tests may be useful in selected cases. Understanding the pathophysiology of fluid balance is necessary for appropriate management. A clinical dehydration scale assessing more physical findings may help to determine dehydration severity. Most dehydrated children can be treated orally; however, intravenous therapy may be indicated in patients with severe volume depletion, in those who have failed oral therapy, or in children with altered consciousness or significant metabolic abnormalities. Proper management consists of restoring circulatory volume and electrolyte balance. In this paper, we review clinical aspects, diagnosis, and management of children with volume depletion.

Eculizumab use in patients with pneumococcal-associated hemolytic uremic syndrome and kidney outcomes

BACKGROUND

Streptococcus pneumoniae-associated hemolytic uremic syndrome (P-HUS) is a rare and severe disease. Only a few reports have been published about eculizumab use in P-HUS.

METHODS

We analyzed demographic, clinical, and laboratory data of patients with P-HUS from our center.

RESULTS

The cohort consisted of 4 females and 3 males. All patients had pneumonia. Four were given eculizumab (days 1-3). The eculizumab group required a shorter duration of dialysis and mechanical ventilation (medians 20 vs. 28.5 and 30 vs 38.5 days, respectively) compared with the non-eculizumab group, but this was still much longer than normally reported; the thrombocytopenia resolution was similar in both groups (medians 10 vs. 8 days). Chronic kidney disease (CKD) was correlated with the duration of dialysis and mechanical ventilation duration at 1 year (r = 0.797, P = 0.032 and r = 0.765, P = 0.045) and last follow-up (r = 0.807, P = 0.028 and r = 0.814, P = 0.026, respectively); our scoring system showed even stronger correlations (r = 0.872, P = 0.011 and r = 0.901, P = 0.0057, respectively). The eculizumab group showed slightly better 1-year and last follow-up CKD stage (2.75 vs. 3, P = 0.879 and 2.5 vs. 3.67, P = 0.517).

CONCLUSIONS

Despite the fact that the eculizumab group showed better outcomes, eculizumab does not seem to improve the course of P-HUS compared with previous reports. Kidney outcomes are strongly correlated with the duration of dialysis and mechanical ventilation duration. A higher resolution version of the Graphical abstract is available as Supplementary information.

Severe Acute Kidney Injury in Children as a Rare Complication of Paroxysmal Cold Hemoglobinuria

Paroxysmal cold hemoglobinuria (PCH) is a rare condition in childhood characterized by complement-mediated premature destruction of red blood cells. PCH is associated with intravascular hemolysis causing hemoglobinuria, which may result in acute kidney injury of various severity. We aimed to retrospectively analyze clinical and laboratory features of children with PCH-associated acute kidney injury received at tertiary Pediatric Hematology and Nephrology Center, University Motol Hospital, Prague, Czech Republic during the period 2016 to 2022. We present here 3 children with PCH-associated acute kidney failure requiring renal replacement therapy. We highlight the association of PCH with kidney disease. Renal parameters and urine examination should be regularly tested in all children with PCH.

Unmeasurable capillary C-reactive protein as one of the diagnostic clues of severe hematological pathologies in children in primary settings: Case series

RATIONALE

The manuscript aimed to show that an unmeasurable capillary C-reactive protein (CRP) should be a red flag that can indicate a possible severe hematological pathology.

PATIENTS CONCERNS AND DIAGNOSES

The authors present 3 case reports of children with fever examined at the pediatric emergency department. Fever is among the most frequently exhibited symptoms of acute pediatric infectious diseases. However, sometimes fever can be the manifestation of other serious noninfectious diseases. CRP is a marker widely used in clinical pediatric practice to help us evaluate inflammation and possible bacterial infection. All mentioned patients had unmeasurable CRP from capillary blood, even though venous CRP ranged from 14 to 21 mg/L. All of the patients were consequently diagnosed with severe hemato-oncological disease. Possible explanations are that a change in blood viscosity or an elevation of circulating immune complexes in the blood of patients with leukemia leads to malfunctioning immunoturbidimetry measurement.

LESSON

Although these findings are very interesting and could lead to faster recognition of acute leukemia in pediatric clinical practice, further prospective study is needed for their confirmation.

Case report: Severe hypertension-induced priapism in an infant with unrecognized autosomal recessive polycystic kidney disease

Priapism is a urologic emergency requiring prompt management. There are three types of priapism: stuttering (intermittent), non-ischemic (high-flow/arterial), and ischemic (low-flow/veno-occlusive). Here, we present the first case of an infant with recurrent non-ischemic priapism as the first sign of severe hypertension. An 11-month-old infant was admitted to the hospital for high-flow priapism. On admission, he was found to have severe hypertension that required a combination of five antihypertensive drugs; abdominal ultrasound showed polycystic kidneys, splenomegaly, and a parenchymal liver lesion. The priapism resolved spontaneously and did not recur again after the initiation of antihypertensive treatment. Genetic analysis confirmed autosomal recessive polycystic kidney disease (ARPKD). We found no other explanation for the priapism, such as genital trauma, hematologic disease, or anything else. Decreased nitric oxide (NO) bioavailability seen in patients with hypertension seems to be the principal mechanism of hypertension causing priapism. This hypothesis is supported by animal models of genetically modified mice lacking nitric oxide synthase. The same mechanism is thought to be the genesis of priapism and other complications, such as pulmonary hypertension, in patients with sickle cell disease. We present a case of severe hypertension-associated priapism in a child with unrecognized ARPKD. The endothelial dysfunction with decreased NO bioavailability seen in patients with hypertension may be the principal pathogenic mechanism.

Cerebral sinovenous thrombosis in children with nephrotic syndrome: systematic review and one new case

Aim

The aim of this review is to provide clinicians with characteristics of children with nephrotic syndrome and cerebral sinovenous thrombosis (CSVT).

Methods

We have reviewed 37 articles of pediatric cases and provided 1 new case. PRISMA guidelines were followed.

Results

Sixty-two patients were included in the review. CSVT was more common in males, usually occurred within 6 months of nephrotic syndrome onset and was found more often in outpatients. The superior sagittal sinus was the most common sinus affected. Non-contrast computed tomography was the most frequent radiologic study performed, with 30% of results negative for CSVT. Headache and vomiting were the most common symptoms while neurologic symptoms were less frequent. Anticoagulation treatment was strongly inconsistent throughout the literature. Thrombosis outcomes were favorable. The most common possible risk factors were corticosteroid treatment, proteinuria and hypoalbuminemia. Four children had a genetic predisposition diagnosed after thrombosis. No markers for anticoagulation prophylaxis seemed to be relevant for the majority of thrombosis occurring in outpatients.

Conclusion

Prophylactic anticoagulation does not seem reasonable to prevent CSVT. Knowledge of nonspecific symptoms and of nephrotic syndrome being a state of hypercoagulation and early use of appropriate radiologic study seem to be of major importance.

Sudden cardiac arrest in a child with Gitelman syndrome: a case report and literature review

Salt-losing tubulopathies are well-recognised diseases predisposing to metabolic disturbances in affected patients. One of the most severe complications can be life-threatening arrhythmias causing sudden cardiac arrest. We present here the first case of a pediatric patient with Gitelman syndrome associated sudden cardiac arrest without precipitating event. A 10-year-old boy collapsed due to ventricular fibrillation in the Prague tram. Lay cardiopulmonary resuscitation was initiated and external defibrillation restored sinus rhythm within minutes. Initial laboratory examination revealed severe hypokalemia requiring large amounts of electrolyte supplementation. Genetic testing focused to tubulopathies was performed and the diagnosis of Gitelman syndrome was made following the identification of two pathogenic variants in SLC12A3 gene (c.2633 + 1G>A and c.2221G>A). Implantable cardioverter-defibrillator was implanted to prevent sudden cardiac death. The patient was in a good clinical condition with satisfactory electrolyte serum levels at the last follow-up. Causes of electrolyte abnormalities in children should be identified early to prevent the development of rare but potentially fatal complications.

Cyclosporin A in combination with corticosteroids as a treatment for immunoglobulin A vasculitis nephritis in children

BACKGROUND

Immunoglobulin A vasculitis is the most common vasculitis in children. It is usually a self-limiting condition, and the long-term prognosis depends on the severity of renal involvement. Although cyclosporin A is not generally recommended for the management of moderate immunoglobulin A vasculitis nephritis, a few previous reports showed its efficacy. Our aim was to determine whether the treatment with cyclosporin A in combination with corticosteroids is safe and effective for moderate pediatric immunoglobulin A vasculitis nephritis.

METHODS

Nine children underwent treatment. Mean follow-up was 3.1±1.6 (1.4-5.8) years.

RESULTS

All children (seven females and two males) reached complete remission (65.8±27.6 [24-99]) days. No patient had relapse, one patient had slightly impaired kidney function (glomerular filtration rate 84.4 mL/min/1.73 m²), and two patients had microscopic hematuria without proteinuria at last follow-up. One patient with delayed treatment had microscopic hematuria at last follow-up and developed early albuminuria after cessation of immunosuppression. We observed no serious complications or side effects of the treatment.

CONCLUSIONS

Cyclosporin A in combination with corticosteroids seems to be a safe and effective treatment for moderate immunoglobulin A vasculitis nephritis. More studies with cyclosporin A should be conducted to better determine the best therapeutic approach.

Diagnostic and therapeutic management of vesico-ureteral reflux in pediatric kidney transplantation-Results of an online survey on behalf of the European Society for Paediatric Nephrology

BACKGROUND

Vesico-ureteral reflux (VUR) is considered to be a risk factor for recurrent febrile urinary tract infections and impaired renal transplant survival.

METHODS

An online survey supported by the European Society for Paediatric Nephrology was designed to evaluate current management strategies of VUR in native and transplanted kidneys of recipients aged <18 years.

RESULTS

Seventy-three pediatric transplant centers from 32 countries contributed to the survey. All centers performed urological evaluation prior to pediatric kidney transplantation (KTx) with subsequent interdisciplinary discussion. Screening for VUR in native kidneys (30% in all, 70% in selected patients) led to surgical intervention in 78% (11% in all, 89% in selected patients) with a decided preference of endoscopic intervention over ureterocystoneostomy. Following KTx, continuous antibiotic prophylaxis was applied in 65% of the patients and screening for allograft VUR performed in 93% of selected patients. The main management strategies of symptomatic allograft VUR were continuous antibiotic prophylaxis (83%) and surgical treatment (74%) (endoscopic intervention 55%, redo ureterocystoneostomy 26%).

CONCLUSIONS

This survey demonstrates the high variability in the management of VUR in pediatric KTx recipients, points to knowledge gaps, and might serve as a starting point for improving the care for patients with VUR in native and transplanted kidneys.

Schimke immunoosseous dysplasia: an ultra-rare disease. a 20-year case series from the tertiary hospital in the Czech Republic

BACKGROUND

Schimke immunoosseous dysplasia (SIOD) is an ultra-rare inherited disease affecting many organ systems. Spondyloepiphyseal dysplasia, T-cell immunodeficiency and steroid resistant nephrotic syndrome are the main symptoms of this disease.

CASE PRESENTATION

We aimed to characterize the clinical, pathological and genetic features of SIOD patients received at tertiary Pediatric Nephrology Center, University Hospital Motol, Prague, Czech Republic during the period 2001-2021. The mean age at diagnosis was 21 months (range 18-48 months). All patients presented with growth failure, nephropathy and immunodeficiency. Infections and neurologic complications were present in most of the affected children during the course of the disease.

CONCLUSIONS

Although SIOD is a disease characterized by specific features, the individual phenotype may differ. Neurologic signs can severely affect the quality of life; the view on the management of SIOD is not uniform. Currently, new therapeutic methods are required.

Abnormal kidney ultrasound and function in a five-year-old boy born prematurely with a birth weight of 370 grams

It is known that prematurity and low birth weight are associated with chronic kidney disease and hypertension. A positive correlation between kidney volume and birth weight was also described. In our ongoing observational study in 5-year-old children, we perceived highly abnormal kidney ultrasound and functions of a male patient born weighing 370 grams. It was his first nephrology examination since discharge from the hospital. We believe that thorough follow up and timely diagnosis of developing renal insufficiency may help us to initiate proper treatment in high-risk children (Tab. 1, Fig. 1, Ref. 7). Text in PDF www.elis.sk Keywords: prematurity; extremely low birth weight; chronic kidney disease; renal ultrasound; renal function.

Practical recommendations for the management of children after kidney and liver transplantation

The number of pediatric solid organ transplantations is growing. This therapy leads often to better quality of life but also brings some specific complications. Our review summarizes practical recommendations for long-time care of the children after kidney and liver transplantation. The knowledge of the issues related to transplantation is essential for the first contact physicians, whose cooperation with transplant centre contributes highly to adequate management of these children.

Clinical and genetic characteristics of Dent's Disease type 1 in Europe

Background

Dent's disease type 1 (DD1) is a rare X-linked nephropathy caused by CLCN5 mutations, characterized by proximal tubule dysfunction, including low-molecular-weight proteinuria (LMWP), hypercalciuria, nephrolithiasis-nephrocalcinosis, progressive chronic kidney disease (CKD) and kidney failure (KF). Current management is symptomatic and does not prevent disease progression. Here we describe the contemporary DD1 picture across Europe to highlight its unmet needs.

Methods

A physician-based anonymous international e-survey supported by several European Nephrology Networks/Societies was conducted. Questions focused on DD1 clinical features, diagnostic procedure and mutation spectrum.

Results

Two-hundred seven DD1 male patients were reported, being clinical data available for 163 with confirmed CLCN5 mutations. Proteinuria was the most common leading manifestation (49.1%). During follow-up, all patients showed LMWP, 66.4% nephrocalcinosis, 44.4% hypercalciuria and 26.4% nephrolithiasis. After 5.5 years, ∼50% of patients presented renal dysfunction, 20.7% developed CKD ≥ 3, and 11.1% KF. At last visit, hypercalciuria was more frequent in pediatric patients than in adults (73.4% vs. 19.0%). Conversely, nephrolithiasis, nephrocalcinosis and renal dysfunction were more prominent in adults. Furthermore, CKD progressed with age. Despite no clear phenotype/genotype correlation was observed, decreased glomerular filtration rate was more frequent in subjects with CLCN5 mutations affecting the pore or CBS domains compared to those with early-stop mutations.

Conclusions

Results from this large DD1 cohort confirm previous findings and provide new insights regarding age and genotype impact on CKD progression. Our data strongly support that DD1 should be considered in male patients with CKD, nephrocalcinosis/hypercalciuria and non-nephrotic proteinuria and provide additional support for new research opportunities.

Alteration in DNA-binding affinity of Wilms tumor 1 protein due to WT1 genetic variants associated with steroid - resistant nephrotic syndrome in children

Approximately one third of children with steroid-resistant nephrotic syndrome (SRNS) carry pathogenic variants in one of the many associated genes. The WT1 gene coding for the WT1 transcription factor is among the most frequently affected genes. Cases from the Czech national SRNS database were sequenced for exons 8 and 9 of the WT1 gene. Eight distinct exonic WT1 variants in nine children were found. Three children presented with isolated SRNS, while the other six manifested with additional features. To analyze the impact of WT1 genetic variants, wild type and mutant WT1 proteins were prepared and the DNA-binding affinity of these proteins to the target EGR1 sequence was measured by microscale thermophoresis. Three WT1 mutants showed significantly decreased DNA-binding affinity (p.Arg439Pro, p.His450Arg and p.Arg463Ter), another three mutants showed significantly increased binding affinity (p.Gln447Pro, p.Asp469Asn and p.His474Arg), and the two remaining mutants (p.Cys433Tyr and p.Arg467Trp) showed no change of DNA-binding affinity. The protein products of WT1 pathogenic variants had variable DNA-binding affinity, and no clear correlation with the clinical symptoms of the patients. Further research is needed to clarify the mechanisms of action of the distinct WT1 mutants; this could potentially lead to individualized treatment of a so far unfavourable disease.

Diagnosis and management of hypernatraemia in children

Hypernatraemia is most commonly caused by excessive loss of solute-free water or decreased fluid intake; less often, the aetiology is salt intoxication. Especially infants, young children and individuals with a lack of access to water are at risk of developing hypernatraemia. Diagnosis is based on detailed history, physical examination and basic laboratory tests. Correction of hypernatraemia must be slow to prevent cerebral oedema and irreversible brain damage. This article reviews the aetiology, differential diagnosis and management of conditions associated with paediatric hypernatraemia. Distinguishing states with water deficiency from states with salt excess is important for proper management of hypernatraemic patients.

Bartter and Gitelman syndromes

Bartter and Gitelman syndromes belong to salt-losing tubulopathies. These rare diseases may be associated with severe electrolyte disorders. Early identification of tubulopathies is essential for appropriate management. Progress in molecular genetics enabled the identification of genes and pathophysiologic mechanisms associated with these diseases. Here, we review etiology and diagnostics of these disorders from the light of current knowledge. Additionally, we discuss contemporary therapeutic approaches.

Tubuloglomerular Disease With Cone-Shaped Epiphyses Associated With Hypomorphic Variant and a Novel p.Cys14Arg in the TTC21B Gene: A Case Report

Monogenic nephrotic syndrome (NS) is associated with a resistance to initial glucocorticoid therapy and causative variants, which may be found in several genes influencing podocyte stability and kidney development. The TTC21B gene, which encodes the retrograde intraflagellar transport protein IFT139, is found mostly in association with ciliopathies in humans. The role of this protein in podocyte cytoskeleton stability was confirmed later and the mutated TTC21B also may be associated with proteinuric diseases, such as nephrotic syndrome. Our patient manifested as an infant with brachydactyly, nephrotic-range proteinuria, and renal tubular acidosis, and a kidney biopsy revealed focal segmental glomerulosclerosis (FSGS). Multiple phalangeal cone-shaped epiphyses of the hand were seen on X-ray. Next-generation sequencing revealed the well-described p.Pro209Leu heterozygous variant and a novel heterozygous p.Cys14Arg variant in the TTC21B gene. Our finding confirmed that the causative variants in the TTC21B gene may contribute to a spectrum of clinical features, such as glomerular proteinuric disease with tubulointerstitial involvement and skeletal abnormalities.

FHR-5 Serum Levels and CFHR5 Genetic Variations in Patients With Immune Complex-Mediated Membranoproliferative Glomerulonephritis and C3-Glomerulopathy

Background

Factor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on CFHR5 variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data.

Methods

A total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the CFHR5 gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR).

Results

Eight exonic CFHR5 variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters.

Conclusions

Our observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.

Aetiology, course and treatment of acute tubulointerstitial nephritis in paediatric patients: a cross-sectional web-based survey

BACKGROUND

Acute tubulointerstitial nephritis (TIN) is a significant cause of acute renal failure in paediatric and adult patients. There are no large paediatric series focusing on the aetiology, treatment and courses of acute TIN.

PATIENTS, DESIGN AND SETTING

We collected retrospective clinical data from paediatric patients with acute biopsy-proven TIN by means of an online survey. Members of four professional societies were invited to participate.

RESULTS

Thirty-nine physicians from 18 countries responded. 171 patients with acute TIN were included (54% female, median age 12 years). The most frequent causes were tubulointerstitial nephritis and uveitis syndrome in 31% and drug-induced TIN in 30% (the majority of these caused by non-steroidal anti-inflammatory drugs). In 28% of patients, no initiating noxae were identified (idiopathic TIN). Median estimated glomerular filtration rate (eGFR) rose significantly from 31 at time of renal biopsy to 86 mL/min/1.73 m² 3-6 months later (p<0.001). After 3-6 months, eGFR normalised in 41% of patients (eGFR ≥90 mL/min/1.73 m²), with only 3% having severe or end-stage impairment of renal function (<30 mL/min/1.73 m²). 80% of patients received corticosteroid therapy. Median eGFR after 3-6 months did not differ between steroid-treated and steroid-untreated patients. Other immunosuppressants were used in 18% (n=31) of patients, 21 of whom received mycophenolate mofetil.

CONCLUSIONS

Despite different aetiologies, acute paediatric TIN had a favourable outcome overall with 88% of patients showing no or mild impairment of eGFR after 3-6 months. Prospective randomised controlled trials are needed to evaluate the efficacy of glucocorticoid treatment in paediatric patients with acute TIN.

Various phenotypes of disease associated with mutated DGKE gene

Atypical haemolytic uraemic syndrome and steroid-resistant nephrotic syndrome are highly rare kidney diseases that can occur in childhood. In some cases, genetic variants may trigger these conditions, although in atypical haemolytic uraemic syndrome they mostly confer only a predisposition to the disease. Most variants causing atypical haemolytic uraemic syndrome were identified in genes encoding proteins regulating the complement pathway; on the other hand, there are approximately 58 genes encoding distinct proteins primarily causing steroid-resistant nephrotic syndrome. We present a child with steroid-resistant nephrotic syndrome and a confirmed homozygous c.966G > A, p.Trp322Ter pathogenic variant in DGKE. This variant was also found in compound with a novel DGKE heterozygous deletion c.171delG, p.Ser58Alafs*111 in a patient from our paediatric cohort with atypical haemolytic uraemic syndrome. Both cases presented with hypertension, nephrotic proteinuria and severe acute kidney injury followed by renal recovery; however, their renal histology was different. In this paper, we deal with the clinical course of children with disrupted DGKE, including the steroid-resistant nephrotic syndrome and atypical haemolytic uraemic syndrome overlap.

Dent Disease Type 2 as a Cause of Focal Segmental Glomerulosclerosis in a 6-Year-Old Boy: A Case Report

Dent disease is an X-linked recessive renal tubular disorder characterized by proximal tubule dysfunction. Typical features include low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, rickets, and chronic renal failure. We present a case of a 6-year-old boy with nephrotic proteinuria without hypoalbuminemia or edema. His renal biopsy revealed focal segmental glomerulosclerosis (FSGS), some of the glomeruli were globally sclerotic. Hypercalciuria was present intermittently and urine protein electrophoresis showed low molecular weight protein fraction of 50%. The next generation sequencing identified pathogenic variant in OCRL gene causing Dent disease type 2. We report an uncommon histologic finding of FSGS in Dent disease type 2 and highlight the importance of protein content examination and genetic analysis for the proper diagnosis in these complicated cases.

C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy

BACKGROUND

Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors.

RESULTS

One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF.

CONCLUSIONS

In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.

Validation of distinct pathogenic patterns in a cohort of membranoproliferative glomerulonephritis patients by cluster analysis

Background

A novel data-driven cluster analysis identified distinct pathogenic patterns in C3-glomerulopathies and immune complex-mediated membranoproliferative glomerulonephritis. Our aim was to replicate these observations in an independent cohort and elucidate disease pathophysiology with detailed analysis of functional complement markers.

Methods

A total of 92 patients with clinical, histological, complement and genetic data were involved in the study, and hierarchical cluster analysis was done by Ward method, where four clusters were generated.

Results

High levels of sC5b-9 (soluble membrane attack complex), low serum C3 levels and young age at onset (13 years) were characteristic for Cluster 1 with a high prevalence of likely pathogenic variations (LPVs) and C3 nephritic factor, whereas for Cluster 2—which is not reliable because of the small number of cases—strong immunoglobulin G staining, low C3 levels and high prevalence of nephritic syndrome at disease onset were observed. Low plasma sC5b-9 levels, decreased C3 levels and high prevalence of LPV and sclerotic glomeruli were present in Cluster 3, and patients with late onset of the disease (median: 39.5 years) and near-normal C3 levels in Cluster 4. A significant difference was observed in the incidence of end-stage renal disease during follow-up between the different clusters. Patients in Clusters 3–4 had worse renal survival than patients in Clusters 1–2.

Conclusions

Our results confirm the main findings of the original cluster analysis and indicate that the observed, distinct pathogenic patterns are replicated in our cohort. Further investigations are necessary to analyse the distinct biological and pathogenic processes in these patient groups.

Genetic diagnosis of steroid-resistant nephrotic syndrome in a longitudinal collection of Czech and Slovak patients: a high proportion of causative variants in NUP93

BACKGROUND

Steroid-resistant nephrotic syndrome (SRNS) has a heterogeneous spectrum of monogenic causes that substantially differ among populations. The aim of this study was to analyse the genetic aetiology of SRNS in Czech and Slovak paediatric patients.

METHODS

We analysed clinical data from 74 patients (38 boys) with congenital (15%), infant (14%), and childhood-onset (71%) SRNS collected from the Czech Republic and Slovakia from 2000 to 2017 (inclusive). The DNA samples were first analysed by Sanger sequencing (genes NPHS2, NPHS1, and WT1) and then by next generation sequencing (NGS) using a targeted panel of 48 genes previously associated with SRNS. Family segregation of the causative variants was confirmed by Sanger sequencing when possible.

RESULTS

Genetic diagnosis was established in 28/74 patients (38%) based on findings of pathogenic or likely pathogenic causative variants in genotypes conforming to the expected mode of inheritance. Sanger sequencing diagnosed 26% of patients, whereas second-tier testing by a targeted NGS panel diagnosed a further 12%. Frequent causative genes were NPHS2 (15%), WT1 (9.5%), and surprisingly NUP93 with four (5.4%) unrelated cases. Additional causative genes included COQ2 (two patients), NPHS1, INF2, DGKE, and LMX1B (one patient each).

CONCLUSIONS

Compared with outright use of NGS, our tiered genetic testing strategy was considerably more rapid and marginally less expensive. Apart from a high aetiological fraction of NPHS2 and WT1 genes, our study has identified an unexpectedly high frequency of a limited set of presumably ancestral causative mutations in NUP93. The results may aid in tailoring testing strategies in Central European populations.

Influenza-associated thrombotic microangiopathies

Thrombotic microangiopathy (TMA) refers to phenotypically similar disorders, including hemolytic uremic syndromes (HUS) and thrombotic thrombocytopenic purpura (TTP). This review explores the role of the influenza virus as trigger of HUS or TTP. We conducted a literature survey in PubMed and Google Scholar using HUS, TTP, TMA, and influenza as keywords, and extracted and analyzed reported epidemiological and clinical data. We identified 25 cases of influenza-associated TMA. Five additional cases were linked to influenza vaccination and analyzed separately. Influenza A was found in 83%, 10 out of 25 during the 2009 A(H1N1) pandemic. Two patients had bona fide TTP with ADAMTS13 activity <10%. Median age was 15 years (range 0.5-68 years), two thirds were male. Oligoanuria was documented in 81% and neurological involvement in 40% of patients. Serum C3 was reduced in 5 out of 14 patients (36%); Coombs test was negative in 7 out of 7 and elevated fibrin/fibrinogen degradation products were documented in 6 out of 8 patients. Pathogenic complement gene mutations were found in 7 out of 8 patients tested (C3, MCP, or MCP combined with CFB or clusterin). Twenty out of 24 patients recovered completely, but 3 died (12%). Ten of the surviving patients underwent plasma exchange (PLEX) therapy, 5 plasma infusions. Influenza-mediated HUS or TTP is rare. A sizable proportion of tested patients demonstrated mutations associated with alternative pathway of complement dysregulation that was uncovered by this infection. Further research is warranted targeting the roles of viral neuraminidase, enhanced virus-induced complement activation and/or ADAMTS13 antibodies, and rational treatment approaches.

Urinary Neutrophil Gelatinase-Associated Lipocalin Does Not Distinguish Acute Rejection from Other Causes of Acute Kidney Injury in Pediatric Renal Transplant Recipients

BACKGROUND

The aim of this prospective single center study was to investigate the ability of urinary neutrophil gelatinase-associated lipocalin (NGAL) to distinguish acute rejection from other causes of acute kidney injury (AKI) in children after renal transplantation.

METHODS

Fifteen children fulfilled the inclusion criteria (acute kidney injury (AKI) with allograft biopsy, at least 21 days after renal transplantation, no sepsis) during 2013 - 2014 in our pediatric transplantation center. The mean age was 14.8  2.8, median time after renal transplantation was 0.4 years (range 0.1 - 3.8). Urinary NGAL was measured in spot urine by Chemiluminescent Microparticle Immunoassay technology.

RESULTS

Four patients had biopsy proven acute rejection (rejection group), eleven children had AKI of other cause (non-rejection group). The median urinary NGAL concentration in the rejection group was not significantly different from NGAL in the non-rejection group (7.3 ng/mL, range 3.0 - 42.3 vs. 8.6 ng/mL, range 3.4 - 54.7, p = 0.48). There was a significant negative correlation between eGFR and urinary NGAL concentrations (r = -0.77, p < 0.001).

CONCLUSIONS

Our small study suggests that in children after renal transplantation, urinary NGAL cannot be used as a specific marker for distinguishing acute rejection from other non-rejection causes of AKI. Urinary NGAL was mainly associated with graft function but not with the etiology of AKI.

Pathophysiology of Hyponatremia in Children

Hyponatremia is a common electrolyte disorder in children. It is generally defined as plasma sodium of less than 135 mmol/l. Sodium homeostasis is essential for maintaining intravascular volume and is tightly linked to water balance. Plasma water volume is regulated mainly by the secretion of an antidiuretic hormone (ADH) and by the thirst mechanism. ADH is synthesized in the hypothalamus and stored in the posterior hypophysis. It binds to V2 receptors in the distal nephron and induces translocation of aquaporin water channels in the plasma membrane to retain water. There are two main types of receptors involved in the control of the body water balance-osmoreceptors and baroreceptors. Osmoreceptors reside in hypothalamus and respond to changes of extracellular fluid (ECF) osmolality. Baroreceptors are mechanoreceptors that sense blood pressure in the vessel wall. Response reflexes from baroreceptors influence sympathetic outflow, vessel tonus, and cardiac output. An increase of 1% of plasma osmolality may cause an increase in ADH levels, while the threshold of volume receptors for ADH secretion is higher. However, significant hypotension is a more potent stimulus for ADH secretion than increased osmolality. The main cause of pediatric hyponatremia is an abundance of free water. This may occur in hypovolemic children with low ECF volume, normovolemic patients with inappropriately increased ADH secretion, and also in hypervolemic individuals with decreased effective circulating volume and appropriately increased ADH levels. Proper understanding of the pathophysiology of hyponatremic states is essential for establishing the correct diagnosis and appropriate therapy.

Recurrence of nephrotic proteinuria in children with focal segmental glomerulosclerosis: early treatment with plasmapheresis and immunoadsorption should be associated with better prognosis

BACKGROUND

Primary focal segmental glomerulosclerosis (FSGS) is a glomerular disease, characterized by progressive renal function deterioration, nephrotic proteinuria, and risk of chronic renal failure. We present long-term results of 5 patients with primary FSGS and recurrence of nephrotic proteinuria after renal transplantation treated with plasma exchange (PE) and immunoadsorption (IA).

METHODS

We retrospectively investigated the relationship between the delay in initiation of the therapy and treatment outcomes, particularly achievement of remission of proteinuria.

RESULTS

Remission occurred in all three patients who started PE/IA in interval 3-7 days after diagnosis of recurrence of FSGS. Remission was achieved after 3-4 weeks in two patients with 3 days of delay to the start of PE. The third patient (PE started with 7 days of delay) reached complete remission after 6 months of PE/IA treatment. All these patients had remission sustainable for a long time. The remaining two patients with 14 and 406 days of delay to PE treatment did not achieve remission sustainable for a long time. The two patients who did not achieve remission developed end-stage renal disease with graft loss (1 and 6.7 years after transplantation). Patients who achieved remission of proteinuria during PE/IA treatment have still functioning grafts (2.8, 9.7 and 3.8 years after renal transplantation). All these patients are still treated with PE/IA.

CONCLUSIONS

The present 5 cases suggest that if recurrence of FSGS occurs, the probability of achieving remission is dependent on the early initiation of PE/IA therapy. Therefore, we suggest that PE/IA treatment might be started as soon as possible after recurrence of FSGS.

Current views on the diagnosis and management of hypokalaemia in children

Hypokalaemia is a common electrolyte disorder in children, caused by decreased potassium intake, increased gastrointestinal and urinary losses or transcellular shift. Patients with severe hypokalaemia may suffer from symptoms such as life-threatening cardiac arrhythmias. The aim of our study was to review the aetiology of hypokalaemia, suggest a diagnostic algorithm and discuss the management of patients with various aetiologies of hypokalaemia.

CONCLUSION

Understanding the pathophysiology of hypokalaemic states, along with a detailed medical history, physical examination and specific laboratory tests are required for proper diagnosis and appropriate treatment.

[Hyponatremia in children: from pathophysiology to therapy]

This present review analyzes the etiology, diagnostics and management of conditions associated with hyponatremia. Excess water and/or sodium wasting lead to the development of hyponatremia in children. There are diverse etiologies associated with hyponatremia, correct diagnosis is based on detailed history, physical examination and basic laboratory tests. Symptomatic hyponatremia can be a life threatening emergency and thus requires fast and vigorous management. Inappropriate treatment may cause fatal consequences.

[Vesicoureteric reflux in children: many questions still unanswered]

Vesicoureteric reflux (VUR) is the most common congenital anomaly of the uropoetic system. The gold standard for its diagnosis is the voiding cystourethrogram. Sonographic cystourethrography is an alternative method for reflux detection, but it is still not used routinely. Static scintigraphy enables us to diagnose renal scarring reflux nephropathy (RN). While congenital RN is a result of prenatal kidney injury, acquired RN results from pyelonephritis-induced renal damage.Risk factors for RN include VUR, recurrent APN, lower urinary tract dysfunction and delay in treatment of febrile urinary tract infection. Management of children after APN with VUR consists of antibiotic prophylaxy, surgery or surveillance only. The conclusions of performed studies are controversial, thus unified guidelines for the management of patients with VUR are not available.

Oral penicillin-associated acute kidney injury in an infant with acute pyelonephritis

Beta-lactam-associated acute tubulointerstitial nephritis (ATIN) is a rare condition in childhood. We report the case of an infant with penicillin-associated ATIN and concomitant acute pyelonephritis resulting in the development of severe acute kidney injury (AKI). The treatment consisted of penicillin suspension and appropriate AKI management, which required a short period of dialysis. Finally, full recovery and normalization of laboratory parameters occurred. We present here the first case of oral penicillin-associated ATIN in childhood.

Evaluation and management of hyponatraemia in children

AIM

Paediatric hyponatraemia is usually caused by an excess of antidiuretic hormone and may lead to serious neurological complications. It is challenging for clinicians to differentiate between conditions causing excess water and salt loss. This review analyses individual causes of hyponatraemia and focuses on optimal diagnostic algorithms and treatment strategies.

CONCLUSION

Correct evaluation of hyponatraemia requires proper understanding of the aetiology and appropriate management calls for a detailed history, physical examination and specific laboratory investigations.