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Artificial intelligence is playing an increasingly important role in many fields of clinical care to assist health care providers in patient management. In adult-focused nephrology, artificial intelligence is beginning to be used to improve clinical care, hemodialysis prescriptions, and follow-up of transplant recipients. This article provides an overview of medical artificial intelligence applications relevant to pediatric nephrology. We describe the core concepts of artificial intelligence and machine learning and cover the basics of neural networks and deep learning. We also discuss some examples for clinical applications of artificial intelligence in pediatric nephrology, including neonatal kidney function, early recognition of acute kidney injury, renally cleared drug dosing, intrapatient variability, urinary tract infection workup in infancy, and longitudinal disease progression. Furthermore, we consider the future of artificial intelligence in clinical pediatric nephrology and its potential impact on medical practice and address the ethical issues artificial intelligence raises in terms of clinical decision-making, health care provider-patient relationship, patient privacy, and data collection. This article also represents a call for action involving those of us striving to provide optimal services for children, adolescents, and young adults with chronic conditions.

Sodium MRI can help measure dynamic changes in the corticomedullary sodium gradient, reflect urine-concentrating ability in healthy volunteers, and provide consistent images for analysis in participants with chronic kidney disease.

Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.

In previous studies, smaller renal volumes were reported in prematurely born infants, however, these renal volumes were not corrected for body surface area, the main determinant of renal size. Given the rapid growth of the renal cortex after premature birth, the authors hypothesized that corrected volumes would not differ from healthy controls.

Twenty-four-hour ambulatory blood pressure monitoring (ABPM) is widely accepted as a more accurate method for measurement of blood pressure (BP) compared to a single office-based measurement of BP. However, it is unclear how physicians interpret ABPM and make management decisions. This study’s goal is to investigate variation in ABPM interpretation among paediatric nephrologists (Canada and UK) and paediatric cardiologists (Canada only) via an online survey. The survey content included baseline demographics, questions on the use and indications for ABPM, interpretation of results, and subsequent management decisions in various clinical scenarios. The survey was sent to 196 Canadian physicians, with 69 (35.2%) total responses. Thirty-five UK clinicians also completed the survey. Most respondents were >44 years old, were in practice for at least 11 years, and were university-based. There were substantial differences among clinicians in ABPM interpretation for isolated systolic, diastolic, and night-time hypertension. For example, only 53.1% of physicians would initiate or modify treatment in those with diastolic HTN in CKD. Further, even for the same abnormal ABPM parameter, the decision to start or alter treatment was influenced by the underlying medical condition. There is significant variation in clinical practice among physicians for interpretation and management of hypertension when using ABPM. Differences in guidelines among various jurisdictions, as well as knowledge gaps in the research on which guidelines are based, create ambiguity regarding ABPM interpretation and management decisions. A more protocolized approach and further insight into the reasoning behind the variation in physicians’ interpretation may help to standardise practice.

Hyperammonaemia in children can lead to grave consequences in the form of cerebral oedema, severe neurological impairment and even death. In infants and children, common causes of hyperammonaemia include urea cycle disorders or organic acidaemias. Few studies have assessed the role of extracorporeal therapies in the management of hyperammonaemia in neonates and children. Moreover, consensus guidelines are lacking for the use of non-kidney replacement therapy (NKRT) and kidney replacement therapies (KRTs, including peritoneal dialysis, continuous KRT, haemodialysis and hybrid therapy) to manage hyperammonaemia in neonates and children. Prompt treatment with KRT and/or NKRT, the choice of which depends on the ammonia concentrations and presenting symptoms of the patient, is crucial. This expert Consensus Statement presents recommendations for the management of hyperammonaemia requiring KRT in paediatric populations. Additional studies are required to strengthen these recommendations.

Focal segmental glomerular sclerosis (FSGS) is 1 of the primary causes of nephrotic syndrome in both pediatric and adult patients, which can lead to end-stage kidney disease. Recurrence of FSGS after kidney transplantation significantly increases allograft loss, leading to morbidity and mortality. Currently, there are no consensus guidelines for identifying those patients who are at risk for recurrence or for the management of recurrent FSGS. Our work group performed a literature search on PubMed/Medline, Embase, and Cochrane, and recommendations were proposed and graded for strength of evidence. Of the 614 initially identified studies, 221 were found suitable to formulate consensus guidelines for recurrent FSGS. These guidelines focus on the definition, epidemiology, risk factors, pathogenesis, and management of recurrent FSGS. We conclude that additional studies are required to strengthen the recommendations proposed in this review.

Mycophenolic acid (MPA), the active compound of mycophenolate mofetil (MMF), is widely used as an antirejection drug after renal transplantation. There is growing evidence supporting the notion that there is substantial variability in the intra- and interpatient exposure to MPA. Drug interactions involving MPA with tacrolimus, steroids, and sirolimus have been understudied. The objective of this study was to determine the relationship between MPA, steroids, tacrolimus, and sirolimus. MPA trough concentrations from 37 pediatric renal transplant recipients (mean age 7.6 years at transplant) followed for a median follow-up of 7.8 years were analyzed retrospectively and 2131 dose-normalized MPA trough concentrations were evaluated against all known covariates including all concomitant immunosuppressant drug doses and exposure, age, albumin, hematocrit, and estimated glomerular filtration rate (eGFR). Age, hematocrit, and estimated glomerular filtration rate affected the dose-normalized MPA trough concentrations. The authors used appropriate linear regression univariate models and created 5 different multivariate models to examine individual drug–drug interactions (DDIs). Although the authors' findings support the notion that there is a DDI between MMF and both sirolimus and steroids, the sample size was small, and these findings should be confirmed in future studies. The authors found no DDIs between tacrolimus and MMF, the prodrug of MPA. These findings are important because there is a tendency to under-dose MMF early and to overdose late after transplantation. The DDI between sirolimus and MMF has not been described. Although therapeutic drug monitoring of MMF therapy is often not performed, the data presented here indicate a necessity for therapeutic drug monitoring. This is especially true when converting from tacrolimus to sirolimus, as a way to avoid MPA underexposure and organ rejection.

Some trace elements are altered with chronic kidney disease. Selenium, zinc, and manganese tend to be wasted, and there is growing evidence that selenium deficiency is associated with mortality on dialysis. Other trace elements accumulate, such as chromium, cobalt, lead, molybdenum, and vanadium. The highest chromium levels are found in dialysis patients. The dialysis modality may further affect these levels, especially in hemodialysis patients, where even small contaminations in the dialysis feed water may lead to a concentration gradient that increases the concentration of certain trace elements. Chromium levels in peritoneal dialysis (PD) patients have been understudied. A single cross-sectional study found substantially higher chromium levels in PD patients. In that study, the chromium concentration in the spent dialysate decreased substantially, suggesting that PD fluid could be a source of chromium. Chromium-lactate complexes may have been formed, which are easily absorbed. In our center, we observed a decrease in chromium level when using physiological PD fluids. This review discusses the potential mechanisms and raises the question of whether this accumulation of chromium is unlikely to be associated with a beneficial outcome.

Responsibility for training general paediatricians in Canada lies primarily with the 17 paediatric academic health sciences centres with more programmatic emphasis on subspecialty training and less on preparing residents for general paediatrics. However, the greatest unmet demand in the paediatric workforce will be for consulting paediatric generalists. Here, we define the need for paediatric generalists and list deficiencies in current models to promote more consulting community general paediatricians. The limited presence of general paediatricians as role models reduces the potential for learners to better understand the role of generalists in our specialty. Nationally, we need to advocate for change in teaching models to guide the career choices of our graduates to meet societal needs through better mentorship and educational models that heavily include community-based paediatric consulting generalists. This will be essential to meet our responsibility of supporting primary care colleagues closer to home for our funders, patients and families.

AbstractBackground:Isotopic glomerular filtration rate (iGFR) measurement is comparable to the inulin method. In this study, we compared urinary and plasma iGFR methodologies in patients with diabetic nephropathy. Methods:A total of 147 patients from 3 sites in the Diabetic Intervention with Vitamins to Improve Nephropathy (DIVINe) trial provided 213 sets of urine and blood collections, at baseline, 18 and 36 months. Results:The mean (with standard deviation) plasma iGFR of 60.7 (24.9) ml/min/1.73 m2compared to urinary iGFR of 52.0 (28.0) ml/min/1.73 m2was statistically significant (p value <0.001). Although plasma and urinary iGFRs were highly related (R2= 0.86), plasma iGFR increasingly overestimated urinary iGFRs at lower GFRs. In contrast to the cross-sectional analyses, the two measures of iGFR were weakly related (R2= 0.32) in regard to patients' change over 18 months of follow-up. Conclusion:Plasma iGFR may not be a suitable method for accurately measuring GFR in patients with advancing degrees of chronic kidney disease from diabetic nephropathy.© 2015 S. Karger AG, Basel

Background Infantile hemangioma is the most common benign, self-limiting tumour of childhood. Treatment is reserved for hemangiomas that obstruct vital structures or cause significant disfigurement. Traditionally, corticosteroids have been the medical treatment of choice. Since 2008, however, propranolol has been rapidly adopted as an effective pharmacological treatment for infantile hemangioma. Published data regarding the long-term side effects of propranolol are currently lacking.Objective To describe the long-term effects of propranolol and corticosteroids on anthropometric measurements (height, body mass index [BMI]) and blood pressure in children.Methods A prospective database analysis of all infantile hemangioma patient visits to the pediatric vascular abnormality clinic at the authors' institution between October 2007 and February 2012 was performed. Anthropometric measures (height and BMI) and blood pressure were analyzed.Results A total of 290 visits (119 patients) to the pediatric vascular abnormality clinic were reviewed. Of these, 18 patients received medical treatment and their anthropometry was analyzed. BMI percentile increased significantly in patients treated with corticosteroids (P=0.0039). Corticosteroid treatment also resulted in a significant decrease in height percentile (P=0.0078). Anthropometric measures did not cross percentiles in children treated with propranolol. A significant decrease in systolic blood pressure was noted in the propranolol group (P=0.03), but no hypotensive values were recorded. Median treatment duration was significantly longer when patients received propranolol (372 versus 133 days; P=0.0033).Conclusion Propranolol for the treatment of infantile vascular abnormalities does not share the unfavourable effects on patient anthropometry that corticosteroids exhibit; however, a longer duration of therapy is required.

Objective:To report a novel approach to the management of tacrolimus intoxication that leads to rapid normalization of serum tacrolimus concentrations. Case Summary:A 9-year-old female renal transplant recipient developed a severe tacrolimus intoxication as a result of prolonged diarrhea, which resulted in acute kidney injury, severe dehydration, and neurological symptoms. We used a combination of intravenous steroids and intravenous phenytoin to normalize the tacrolimus level from 32 to 5 ng/mL in less than 24 hours, with complete resolution of symptoms and signs. Discussion:Tacrolimus intoxication is a rare event but may result in life-threatening complications. Treatment recommendations beyond holding the drug and enzyme induction with phenytoin or phenobarbital are elusive. This approach leads to a relatively slow normalization of the tacrolimus level over 72 hours. The authors hypothesized that additional induction of the p-glycoprotein through steroids was synergistic. Conclusions:The combination of phenytoin and a corticosteroid may be an effective approach that leads to rapid normalization of severely elevated tacrolimus levels.

This article details the effectiveness of using lipoprotein apheresis (LA) rather than plasmapheresis in patients with homozygous familial hypercholesterolemia (HoFH), using results from the first HoFH pediatric patient treated with LA in Ontario. We further detail the barriers involved in adhering to international guidelines by implementing this as a first-line treatment for this condition in Ontario, and the potential savings that would be gained with treating the remaining HoFH patients in this province with LA. A primary barrier has been the division of responsibility that exists in Canada, where the delivery of medical services and the delivery of blood products are separated, artificially discounting the price of plasmapheresis and making it seem like the less expensive option. We would like to implement LA as a first-line therapy, to not only improve patient quality of life and outcomes, but to also to potentially save our federal and provincial governments' taxpayer money.

Concomitant immunosuppression may affect the mycophenolate mofetil exposure. Astellas developed a once-daily modified release formulation of tacrolimus (TacMR) with the potential to reduce the likelihood of nonadherence. It is unknown whether mycophenolic acid (MPA) area under the concentration–time curve (AUC) differs between the 2 tacrolimus (Tac) formulations. In a 2-by-2 crossover design, 20 stable renal transplant recipients on twice-daily Tac either continued their usual Tac therapy (n = 10, group 1) or switched to TacMR for a 12-week period (n = 10, group 2), after which the patients crossed over to the other formulation for another 12-week period. Pharmacokinetic profiles using limited sampling strategies were obtained before randomization (visit 1), and at 12 (visit 2) and 24 weeks (visit 3) at steady state. MPA AUC was calculated using the Pawinski formula. When analyzing visits on Tac, TacMR, and back on Tac combined, the MPA AUC for all 20 patients at baseline was 42.24 (16.98), 37.18 (13.75), and 40.09 (16.69) mg·h·L−1, respectively, which was not statistically significant using repeated measures (P= 0.1327, R2= 0.1109). We conclude that MPA pharmacokinetic profiles are not altered when converting patients from Tac to TacMR.

Introduction:To discuss the significance of the recent observational case series from the Swiss Toxicological Information Centre (STIC). Mycophenolic acid (MPA) and its prodrug mycophenolate mofetil are immunosuppressive agents that are frequently prescribed in renal transplant recipients, and their safety profiles must be established.Areas covered:This case series and systemic literature analysis consists of 15 cases of MPA overdose from the STIC and a systemic analysis of the literature over the past 18 years. This study focuses on acute overdosing, the effects of which are presumably mild. In contrast, the effects of long-term overdosing may be much more severe. Substantial underreporting is likely. The pharmacokinetic monitoring of MPA is rarely performed, which is both striking and does not coincide with findings in academic literature. The scant data on pharmacokinetic monitoring presented demonstrated that MPA has a short terminal half-life, which suggests that decontamination and activated charcoal treatment in acute overdose may not be necessary.Expert opinion:The case series and systematic literature analysis of acute mycophenolate overdose represent an important contribution toward increasing the safety of MPA therapy.

Responsibility for training paediatric medical subspecialists in Canada lies primarily with the 16 academic paediatric departments. There has been no mechanism to assess whether the number of residents in training will meet the needs of currently vacant positions and/or the predicted vacancies to be created by anticipated faculty retirement in the next five years across the different paediatric medical subspecialties.

ABSTRACTObjective:The Broselow Pediatric Emergency Tape (Armstrong Medical Industries, Inc., Lincolnshire, IL) (BT) is a well-established length-based tool for estimation of body weight for children during resuscitation. In view of pandemic childhood obesity, the BT may no longer accurately estimate weight. We therefore studied the BT in children from Ontario in a large recent patient cohort.Methods:Actual height and weight were obtained from an urban and a rural setting. Children were prospectively recruited between April 2007 and July 2008 from the emergency department and outpatient clinics at the London Health Science Centre. Rural children from junior kindergarten to grade 4 were also recruited in the spring of 2008 from the Avon Maitland District School Board. Data for preschool children were obtained from three daycare centres and the electronic medical record from the Maitland Valley Medical Centre. The predicted weight from the BT was compared to the actual weight using Spearman rank correlation; agreement and percent error (PE) were also calculated.Results:A total of 6,361 children (46.2% female) were included in the study. The median age was 3.9 years (interquartile range [IQR] 1.56-7.67 years), weight was 17.2 kg (IQR 11.6-25.4 kg), and height was 103.5 cm (IQR 82-124.4 cm). Although the BT weight estimate correlated with the actual weight (r = 0.95577, p < 0.0001), the BT underestimated the actual weight by 1.62 kg (7.1% ± 16.9% SD, 95% CI -26.0-40.2). The BT had an = 10% PE 43.7% of the time.Conclusions:Although the BT remains an effective method for estimating pediatric weight, it was not accurate and tended to underestimate the weight of Ontario children. Until more accurate measurement tools for emergency departments are developed, physicians should be aware of this discrepancy.

Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH) (SLC34A3gene, OMIM 241530) is an autosomal recessive disorder that results in a loss of function of the sodium-phosphate NPT2c channel at the proximal tubule. Phosphate supplementation rarely improves serum phosphate, hypercalciuria, nephrocalcinosis, 1,25(OH)2vitamin D (1,25(OH)2D) levels or short stature.

This review summarizes the pharmacokinetics in children and youths of 2 commonly used immunosuppressive drugs, mycophenolate mofetil (MMF) and sirolimus (Sir), as presented at the IATDMCT 2007 conference. The review focuses on the developmental changes of drug disposition during childhood and adolescence. Regarding mycophenolate mofetil, the authors were unable to demonstrate age dependency of MMF in combination with cyclosporine. By contrast, there was an inverse relationship between age and the dose-normalized mycophenolate (MPA) area-under-the-time-concentration curve (AUC) in children who received concomitant tacrolimus (Tac). Dose-normalized MPA AUCs were higher than commonly observed in adult patients. It can be hypothesized that the age dependency is related to developmental changes in the expression of the UDP-glucuronosyltransferases. Sirolimus half-life and mean residence time (MRT) are shorter than in adults. Similar to that in adults, there is a profound drug-drug interaction between cyclosporine and Sir. In our own experience, Sir was started at 0.13 ± 0.05 mg/kg/day. The average Sir AUC was 64.9 ± 29.7 ng*h/mL. The median (range) AUC for each metabolite was as follows: 12-hydroxy-Sir, 7.6 (0.2-18.8); 46-hydroxy-Sir, 3.1 (0.0-12.4); 24-hydroxy-Sir, 4.3 (0.0-12.6); piperidine-hydroxy-Sir, 3.5 (0.0-8.3); 39-desmethyl-Sir, 3.6 (0.0-11.3); 16-desmethyl-Sir, 5.0 (0.1-9.9); and di-hydroxy-Sir, 4.3 (0.0-32.5) ng*h/mL. Of the total metabolite AUC, 77.5% was due to hydroxylated metabolites, while 39-O-desmethyl Sir (the main metabolite in adults) comprised only 8.4% of the metabolites. This is clinically relevant, as 39-O-desmethyl Sir shows 86% to 127% cross-reactivity with the Sir immunoassay. Metabolites reached a median AUC of 60% of that of Sir, but the range was 2.6% to 136%. The age dependency of Sir metabolite formation was confirmed in a human liver microsome model. On the basis of the age dependency of piperidine-hydroxy Sir, the authors postulate that the ontogeny of the drug disposition can be largely explained by developmental changes of the CYP2C8 expression. In conclusion, both Sir and MMF drug disposition vary in children and adolescents from adult patients, most likely because of developmental changes of biliary transporters and metabolic enzymes.

Rapidly growing information, published in a large variety of journals, poses a challenge to pediatric transplant physicians. This review aims at summarizing the most important manuscripts published over the last 1–2 years.

Following 10 years of clinical use of mycophenolate mofetil (MMF), a prodrug of mycophenolic acid, the FDA has approved enteric-coated mycophenolate sodium (EC-MPS). EC-MPS was developed to reduce the upper-gastrointestinal (GI) effects of MMF. Unlike oral MMF, where absorption starts in the stomach, EC-MPS releases MPA in the small intestine. Along with the pharmacology and pharmacokinetics, three randomized, controlled clinical trials in solid-organ transplantation, comparing MMF and EC-MPS, are reviewed. Disappointingly, EC-MPS was similar to MMF in efficacy and safety and did not significantly improve the GI side effects. Moreover, bioequivalence dosing has only been established with concomitant ciclosporin. The pharmacokinetic characteristics must be studied in greater detail. EC-MPS is a safe and effective immunosuppressive agent approved for use in the prevention of acute rejection after renal transplantation. However, the anticipated improvement of GI side effects has not been forthcoming.

Assessment of renal function is important. The gold-standard marker is glomerular filtration rate (GFR) measured by inulin clearance normalized to a standard body surface area of 1.73 m2. Inulin, no longer available in North America, has been replaced by nuclear medicine tests such as 51Cr EDTA, 99mTc DTPA and iothalamate clearances. The use of serum creatinine as a surrogate endogenous marker is hampered by height, gender and muscle mass variability,substantial tubular secretion in advanced renal failure and non-standardized measurements. The limitations of creatinine can be reduced when applying height/creatinine ratios with gender and age-dependent constants that have to be established for each center. The small molecular weight protein cystatin CysC shows a significantly better diagnostic performance for the detection of impaired GFR than serum creatinine. It also does not undergo tubular secretion in chronic renal failure, nor does it show significant non-renal elimination. Its concentration falls in the first year of life with the rise of GFR and remains constant thereafter until 60 years of age in both sexes. GFR can be estimated reliably with a recently published formula without the need for any additional anthropological data. CysC allows for reliable estimation of GFR in children.

In adult renal recipients, coadministration of tacrolimus (TAC) and sirolimus (SIR) results in reduced exposure to TAC at SIR doses of 2 mg/day. Eight pediatric renal recipients (median age at transplant 2.0 years, range: 1.2–12.9 years) were converted to TAC- and SIR-based immunosuppression as a rescue therapy. All patients had biopsy-proven chronic allograft nephropathy. TAC levels were measured using a commercially available EMIT assay and SIR levels with a newly developed assay based on the LC-MS MS technology. SIR was started at 0.13 ± 0.05 mg/kg/day (3.51 ± 1.26 mg/m2/day) in two divided doses. TAC was given at 0.14 ± 0.09 mg/kg/day, resulting in a trough level of 6.3 ± 2.5 ng/mL. After the addition of SIR, the median dose required to keep TAC blood trough concentrations within the target range increased by 71.2% (range: 21.9–245.4%), dose-normalized TAC exposure (AUC) decreased to 67.1% and the dose-normalized Cmax, a surrogate for absorption rate, to 53.8% (both geometric means) while terminal half-life (t1/2), a pharmacokinetic parameter characterizing systemic elimination, remained unchanged (p < 0.93). Adding SIR to TAC-based immunosuppression in young pediatric renal transplant recipients results in a significant decrease of TAC exposure. TAC trough levels should be monitored frequently.

AbstractBackground: There is considerable interest in using continuous venovenous hemofiltration machines for plasma exchange therapy in children. Methods: Retrospective study of 7 patients and 61 plasma exchange treatments using the Baxter/Edwards Lifesciences BM25 machine with commercially available plasma filters (mostly Asahi Plasmaflo). Results: The average total exchange volume was 1.5 times the plasma volume, achieved at a blood flow rate of 100 ml/m2 (3.5 ml/kg/min) and a turnover rate of 25 ml/kg/h over a 3-hour duration. Fifty-six percent of the time, a mean heparin bolus of 29 units/kg resulted in subtherapeutic activated clotting times. Mean heparin infusion rates of 35 units of heparin/kg/h achieved effective anticoagulation. A calcium infusion rate of 0.11 ± 0.05 mmol/kg/h avoided hypocalcemia. One patient experienced the serious complication of membrane reaction. Conclusions: This setup provides a safe approach to plasma exchange in children. A similar method could be implemented in other centers.Copyright © 2005 S. Karger AG, Basel

Background:Autosomal dominant polycystic kidney disease (ADPKD) ranks among the most common genetic disorders. The development of end-stage renal failure usually is after the fourth decade of life. Angiotensin-converting enzyme (ACE) inhibitors often are used as agents to slow the progression of renal failure, although their effectiveness and starting point in ADPKD remain unclear. Methods:We measured technetium 99m diethylenetriamine pentaacetic acid glomerular filtration rate (GFR) and serum cystatin C (Cys-C) levels in 18 children with ADPKD and 41 control patients. Data are given as mean ± SD. Mean age was 9.8 ± 5.9 years, mean height was 137.5 ± 34.3 cm, and mean weight was 39.2 ± 22.8 kg in the ADPKD group, not significantly different from controls, with an average age of 10.4 ± 4.9 years, height of 138.0 ± 26.1 cm, and weight of 38.0 ± 16.8 kg. Results:Mean serum creatinine levels did not differ between the ADPKD (0.6 ± 0.2 mg/dL [51.1 ± 20.4 μmol/L]) and control groups (0.7 ± 0.2 mg/dL [59.8 ± 15.3 μmol/L]; P= 0.19). Mean GFR was 142 ± 33.2 mL/min/1.73 m2in the ADPKD group, significantly greater than that in controls (110 ± 12 mL/min/1.73 m2; P< 0.0001). Mean Cys-C level for the ADPKD group was 0.71 ± 0.11 mg/L, significantly lower than that of controls (0.81 ± 0.12 mg/L; P= 0.0011). No patient with ADPKD had hypertension, and only 1 patient had minimal microalbuminuria. Although renal length on ultrasound was significantly increased, there was no correlation between renal length and GFR or number of cysts. Conclusion:Therefore, the high GFR measurements represent early hyperfiltration in children and adolescents with ADPKD, which may give a rationale to start ACE inhibitor therapy.

Background:Reports on the worldwide increase in focal segmental glomerulosclerosis (FSGS) in childhood may have been hampered by referral bias. A true increase in FSGS possibly could alter the current practice of withholding renal biopsy in childhood nephrotic syndrome (NS) unless the patient fails to respond to a 28-day course of corticosteroid therapy. Methods:With these questions in mind, we analyzed a 17-year database covering a 275,000-child population with mandatory referral. The incidence of NS per 100,000 childhood population per year was calculated, charts of 159 patients with NS seen between 1985 and 2002 were reviewed, and a receiver operating characteristic (ROC) plot analysis was performed to analyze the diagnostic performance of remission time. Results:Results show that 115 of 159 patients had minimal change NS, diagnosed either on the basis of corticosteroid response (n = 89), verified by renal biopsy (n = 14), or with minimal change plus mesangial immunoglobulin M on histological examination (n = 12). The remaining 44 patients underwent a renal biopsy showing FSGS (n = 29; 18.2%), diffuse mesangial hypercellularity (n = 8; 5%), membranoproliferative glomerulonephritis (n = 1; 0.6%), membranous nephropathy (n = 3; 1.9%), or other diagnoses (n = 3). The incidence of FSGS increased significantly (P= 0.0253) from 0.37 to 0.94/100,000-child population/y in the two 8½-year intervals of our study. ROC plot analysis confirmed diagnostic sensitivity and specificity greater than 80% for remission time between 21 and 28 days of therapy. Conclusion:We confirm the increasing incidence of FSGS in children with idiopathic NS in a well-defined catchment area and, at the same time, find no reason to change the initial therapy and current indications to perform renal biopsy in childhood NS.

Combined liver-kidney transplantation is the definitive treatment for end-stage renal disease caused by primary hyperoxaluria type I (PH1). The infantile form is characterized by renal failure early in life, advanced systemic oxalosis, and a formidable mortality rate. Although others have reported on overall results of transplantation for PH1 covering a wide age spectrum, none has specifically addressed the high-risk infantile form of the disease.

Aim. To determine the sequential therapy of childhood nephrotic syndrome (NS) with presumed minimal change nephropathy using the evidence from clinical trials.Methods. Meta-analysis of 22 randomized controlled trials was performed, using frequency of relapse and side effects of therapeutic regimes.Results. A meta-analysis of seven trials comparing duration of therapy for initial onset showed that duration of at least 3 months significantly reduced the risk of relapse at 12-24 months (relative risk 0.73; 95% confidence interval 0.60-0.89) without an increase in adverse events. Five trials were performed for steroid treatment of relapse. Deflazacort reduced relapses during therapy, but is not generally available. No difference was observed when comparing single and divided dosing of prednisone. Frequency of relapses could not be influenced by duration of relapse therapy. Alternate day therapy was more effective than intermittent use of prednisone. Two studies out of five on cyclophosphamide or chlorambucil showed consistently that alkylating agents should be used before cyclosporine as alternative therapy to steroids.Conclusions. Children with initial onset of NS should be treated with prednisone at a dose of 60 mg/m²/day for 6 weeks, followed by a dose of 40 mg/m²/48 h for at least another 6 weeks. If steroid toxicity for treatment of relapsing NS requires alternative treatment, cyclophosphamide (2 mg/kg/day for at least 8 weeks) remains the drug of choice with a curative potential. If children still relapse after alkylating agents, levamisole may serve as an alternative only for frequent relapsing NS, whereas steroid-dependent NS should be treated with cyclosporine.

We compared the diagnostic performance of cystatin C and β-trace protein with serum creatinine and the Schwartz formula for the estimation of glomerular filtration rate in children with spina bifida.

Background:Infections caused by herpes virus, in particular, Epstein-Barr virus (EBV), remain a major challenge in solid organ transplantation. Little is known about the significance of tissue EBV load. Methods:Twenty-three tissue biopsy specimens (19 kidney, 3 gastrointestinal, and 1 tonsil specimen) and 2 bronchoalveolar lavage specimens from 14 pediatric transplant recipients (10 kidney, 3 liver, 1 combined transplant) were subject to tissue EBV polymerase chain reaction (PCR) semiquantitative analysis and enzyme-linked immunosorbent assay (ELISA) methods. Results of biopsies were correlated with clinical data. Results:Five of 14 patients had clinically diagnosed EBV disease: 2 patients presented with a septic picture with multiorgan failure and pneumonitis; 1 patient had mononucleosis; 1 patient had an increase in serum creatinine level, lymphadenopathy, and chronic fatigue; and 1 patient had EBV nephritis. These 5 patients underwent 12 biopsies at the time of clinically active infection; 8 biopsies had positive results (up to 111 copies/10 μL of extracted DNA). Conversely, 1 of the remaining 13 tissue biopsy specimens from asymptomatic patients had positive results on ELISA, but undetectable viral load, whereas 8 patients had a positive EBV immunoglobulin G titer with historic evidence of EBV replication in the blood. No patient without evidence of EBV had positive EBV tissue PCR results. Conclusion:Increased EBV load was found in more than 50% of patients, pointing to a previously underrecognized importance of EBV detection in tissues from transplant recipients. The presence of EBV in tissue correlated with the presence of viremia, whereas tissue PCR had 100% specificity. EBV load should be included in biopsy evaluation. Am J Kidney Dis41:212-219. © 2003 by the National Kidney Foundation, Inc.

Pharmacokinetic monitoring has been insufficiently studied in paediatric solid organ transplantation, especially because some agents are relatively new to paediatric use, are of new formulation modification or are being used in combinations not previously well studied. The choice of immunosuppressive drugs after paediatric renal transplantation is increasing. Cyclosporine A (CyA), tacrolimus and mycophenolate mofetil (MMF) use has become routine. While pharmacokinetic monitoring of CyA and tacrolimus is routine, few paediatric data on tacrolimus pharmacokinetics exist, and, for MMF, pharmacokinetic monitoring is performed in only a few Canadian centres. The aim of the present article is to provide guidelines for the use of these three drugs by using a large number of full pharmacokinetic profiles in children.

Mycophenolic acid (MPA), the active compound of mycophenolate mofetil (MMF), shows substantial interindividual and intraindividual variability. It was recently shown that in vitro calcineurin inhibitors alter the bioavailability of MPA by dose-dependent inhibition of MPA glucuronidation. The authors retrospectively analyzed full 10-point profiles for both MPA and cyclosporine (CyA) in 23 pediatric patients receiving MMF and cyclosporine microemulsion (Neoral; Novartis Pharmaceuticals Canada; Dorval, Quebec, Canada). Mycophenolic acid was measured using a commercially available EMIT (Novartis Pharmaceuticals, Canada) assay. As the majority of patients were treated with low doses of cyclosporine after adding MMF, the area under the concentration–time curve (AUC) for cyclosporine showed a wide scatter ranging from 296 to 6400 ng × h/mL. The mean cyclosporine dose was 100 ± 76 mg/m 2per day (range 28 to 331). There was no correlation between MPA AUC and MPA dose, and there was substantial interindividual variation. However, there was a significant negative correlation between dose-normalized MPA AUC and cyclosporine AUC (r20.23, p < 0.0220). When dividing the MPA profiles into two groups (11 and 12 patients) with a CyA AUC less than or greater than 1600 ng × h/mL, there was a significantly higher 8-hour concentration in the patients with the lower CyA AUC, secondary to a higher second peak. The data demonstrate that the cyclosporine AUC is a determining factor for the MPA AUC and that MPA dose should be reduced when cyclosporine dose is reduced to achieve the same MPA AUC. The significantly higher peak in the group with a lower CyA profile supports the concept of a dose-dependent cyclosporine-induced inhibition of MPA glucuronidation.

Abstract: Cyclosporine (CyA) has made a great impact on 1-year allograft survival, however, after years, renal function deteriorates, possibly due to chronic toxicity. Recently, Mycophenolate mofetil (MMF) was introduced as a non-nephrotoxic immunosuppressant that might be effective in chronical transplant arteriolopathy. We therefore started MMF at a dose of 600 mg/m2 b. i. d. in 18 pediatric renal transplant recipients (10.8 ± 3.9 (SD) years of age at transplantation, 11/18 with a history of rejections) with biopsy-proven chronic arteriolopathy and other signs of CyA toxicity at a mean follow up time of 6.2 ± 2.7 (range 2.3–11.8) years after transplantation. One month prior to conversion, mean serum creatinine was 171 ± 96 μmol/l, lower than at the time of conversion (188 ± 100 μmol/l, P = 0.003, paired t-test). At last follow-up (median 13.7 months, range 5.0 to 25.0 months) after conversion, mean serum creatinine decreased significantly to 127 ± 69 μmol/l (P = 0,0003, paired t-test). The CyA dosage was reduced from a mean of 150 ± 39 mg/m2 per day to 59 ± 13 mg/m2 per day in 7 patients, and CyA was discontinued in 11 patients after a median period of nine months (range 1–18 months). After a median period of 21 days, a pharmacokinetic profile was performed in all patients. The mean MMF dose was 1117 ± 319 mg/m2 per day (range 675–1774 mg/m2 per day). The mean Mycophenolic acid (MPA) trough concentration was 4.0 ± 2.0 μg/ml, range 1.4–7.9 μg/ml. Mean 12 h MPA AUC was 70.6 ± 28.1 (range 31.9–127) μg × h/ml. Except for one patient with diarrhea associated with a high AUC, and for one patient with a steroid-sensitive rejection episode after 566 days, no other patient experienced side effects or a rejection episode. Prednisolone was left unaltered at 2–4 mg/m2 per day. We conclude that MMF allows safe reduction of CyA with markedly better graft function, suggesting that chronical CyA-toxicity partially accounts for deteriorating allograft function.

This study evaluates glucose metabolism and insulin secretion in children with Ullrich-Turner syndrome (UTS), chronic renal failure (CRF) and kidney transplantation (KTx) with rh GH therapy using an intravenous glucose infusion test. Before treatment, glucose AUC was significantly increased in all patient groups when compared to normal controls. Both the early and second phases of insulin secretion were not altered. During treatment, elevated glucose AUC showed a further increase in patients with KTx but not in patients with CRF or UTS. Both the early and second insulin secretion phases rose significantly in UTS and were transiently elevated after 6 and 12 months of therapy in patients with CRF and KTx. We conclude that growth hormone therapy aggravates alteration of glucose metabolism in patients with KTx and not in children with CRF and UTS. Progressive hyperinsulinemia occurred only in patients with UTS.

There is evidence of neutrophil involvement in the pathogenesis of the haemolytic uraemic syndrome (HUS), and neutrophil release products are thought to cause endothelial cell damage. Elastase is the major lysosmal proteinase liberated by activated neutrophils. In this study we measured both free and complexed elastase. No free elastase activity could be detected in the plasma of patients with diarrhoea-associated (D+) HUS using a specific substrate. However, there was a marked increase in a1-antitrypsin (a1-AT) complexed elastase as measured by a newly developed enzyme-linked immunosorbent assay not only in D+ HUS, but also in non-diarrhoea-associated (D-) HUS. This finding is independent of either a high polymorphonuclear leucocyte count or renal failure. This increase in bound elastase together with our sequential data which demonstrate raised a1-AT complexed elastase levels early in the disease process further support the theory that neutrophil activation is one of the key events in the pathophysiology of this disorder.

This review summarizes the focus shift from ischemia-reperfusion injury and avoidance of rejection to long-term outcome after pediatric renal transplantation over the past decade. Although there has been excellent 1-year graft and patient survival, low rejection rates can be achieved with modern immunosuppression after pediatric renal transplantation, and patient survival is improved substantially in comparison with dialysis, pediatric renal transplant recipients experience a high prevalence of infections, malignancies, medication side effects, nonadherence, and, most importantly, cardiovascular morbidity and mortality. Additional challenges occur because of a high prevalence of obesity after transplantation and vascular calcifications. There is also in an underappreciation of chronic kidney disease (CKD) in transplant recipients. The etiology of CKD is multifactorial and can affect graft and patient survival. The rigors of treatment for CKD are less compared with CKD in nontransplant recipients. Almost all immunosuppressive drugs are implicated with a risk of hypertension, hyperlipidemia, and diabetogenicity, all of which contribute to cardiovascular morbidity. Corticosteroids exhibit the most substantial risk and also stunt growth. Effective new treatment protocols such as the recent European Tacrolimus and WIthdrawal of STeroids (TWIST) study with rapid steroid withdrawal after 5 days provide promising results without increasing the rejection risk. The shift in focus on long-term complications allows for improved graft outcome. Side effects of immunosuppressive medications require continued attention to further improve long-term outcomes.