Acute kidney injury in children hospitalised for febrile urinary tract infection

AIM

To determine (i) prevalence and the risk factors for acute kidney injury (AKI) in children hospitalised for febrile urinary tract infection (fUTI) and (ii) role of AKI as indicator of an underlying VUR. AKI, in fact, is favoured by a reduced nephron mass, often associated to VUR.

METHODS

This retrospective Italian multicentre study enrolled children aged 18 years or younger (median age = 0.5 years) discharged with a primary diagnosis of fUTI. AKI was defined using Kidney Disease/Improving Global Outcomes serum creatinine criteria.

RESULTS

Of 849 children hospitalised for fUTI (44.2% females, median age 0.5 years; IQR = 1.8), 124 (14.6%) developed AKI. AKI prevalence rose to 30% in the presence of underlying congenital anomalies of the kidney and urinary tract (CAKUT). The strongest AKI predictors were presence of CAKUT (OR = 7.5; 95%CI: 3.8-15.2; p = 9.4e-09) and neutrophils levels (OR = 1.13; 95%CI: 1.08-1.2; p = 6.8e-07). At multiple logistic regression analysis, AKI during fUTI episode was a significant indicator of VUR (OR = 3.4; 95%CI: 1.7-6.9; p = 0.001) despite correction for the diagnostic covariates usually used to assess the risk of VUR after the first fUTI episode. Moreover, AKI showed the best positive likelihood ratio, positive predictive value, negative predictive value and specificity for VUR.

CONCLUSION

AKI occurs in 14.6% of children hospitalised for fUTI and is a significant indicator of VUR.

De Novo Large Deletions in the PHEX Gene Caused X-Linked Hypophosphataemic Rickets in Two Italian Female Infants Successfully Treated with Burosumab

Pathogenic variants in the PHEX gene cause rare and severe X-linked dominant hypophosphataemia (XLH), a form of heritable hypophosphatemic rickets (HR) characterized by renal phosphate wasting and elevated fibroblast growth factor 23 (FGF23) levels. Burosumab, the approved human monoclonal anti-FGF23 antibody, is the treatment of choice for XLH. The genetic and phenotypic heterogeneity of HR often delays XLH diagnoses, with critical effects on disease course and therapy. We herein report the clinical and genetic features of two Italian female infants with sporadic HR who successfully responded to burosumab. Their diagnoses were based on clinical and laboratory findings and physical examinations. Next-generation sequencing (NGS) of the genes associated with inherited HR and multiple ligation probe amplification (MLPA) analysis of the PHEX and FGF23 genes were performed. While a conventional analysis of the NGS data did not reveal pathogenic or likely pathogenic small nucleotide variants (SNVs) in the known HR-related genes, a quantitative analysis identified two different heterozygous de novo large intragenic deletions in PHEX, and this was confirmed by MLPA. Our molecular data indicated that deletions in the PHEX gene can be the cause of a significant fraction of XLH; hence, their presence should be evaluated in SNV-negative female patients. Our patients successfully responded to burosumab, demonstrating the efficacy of this drug in the treatment of XLH. In conclusion, the execution of a phenotype-oriented genetic test, guided by known types of variants, including the rarest ones, was crucial to reach the definitive diagnoses and ensure our patients of long-term therapy administration.

Pediatric Minimal Change Disease and AKI following the Pfizer-BioNTech COVID-19 Vaccine: causal or incidental correlation?

The global coronavirus 2019 (COVID-19) pandemic required vaccination even in children to reduce infection. We report on the development of acute kidney injury (AKI) and minimal change disease (MCD) nephrotic syndrome (NS), shortly after the first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). A 12-year-old previously healthy boy was referred to our hospital with complaints of peripheral edema and nephrotic range proteinuria. Nine days earlier he had received his first injection BNT162b2 COVID-19 vaccine (Pfizer-BioNTech). Seven days after injection, he developed leg edema, which rapidly progressed to anasarca with significant weight gain. On admission, serum creatinine was 1.3 mg/dL and 24-hour urinary protein excretion was 4 grams with fluid overload. As kidney function continued to decline over the next days, empirical steroid treatment and renal replacement therapy with ultrafiltration were started and kidney biopsy was performed. Seven days after steroid therapy, kidney function began to improve, gradually returning to normal. The association of MCD, nephrotic syndrome and AKI hasn't been previously described following the Pfizer-BioNTech COVID-19 vaccine in pediatric population, but this triad has been reported in adults. We need further similar case reports to establish the real incidence of this possible vaccine side effect.

P1814ATYPICAL FEATURES IN A TYPICAL DISEASE: ONE THOUSANDS FACES OF IGA NEPHROPATHY IN PAEDIATRIC PATIENTS

Background and Aims

Immunoglobulin A Nephropathy (IgAN) is the most common cause of idiopathic glomerulonephritis in paediatric patients.

The typical presentation is characterized by recurrent episodes of macroscopic haematuria or persistent microhaematuria with mild or overt proteinuria. Renal function is normally preserved, though a slow progression to chronic kidney disease (CKD) may occur.

However, in rare cases IgAN may assume atypical features, presenting with nephrotic syndrome (NS), acute kidney injury (AKI) or assuming the characteristic of a rapidly progressive glomerulonephritis, leading to significant difficulties in management and critical impact on prognosis.

Method

Of total 756 renal biopsies performed in our centre from 2000 till 2019, 174 (23%) diagnosis of IgA nephropathy were made: 123 (70,6%) of 174 with a milder histological stage (I or II according to Lee’s) and 51 (29,3%) with severe stages (III-IV).

Clinical onset of these 51 patients was mostly characterized by a nephritic syndrome with micro-macrohaematuria, though in 7 of them it assumed atypical features (table 1).

Results

Patients 1, 2, 3 and 4 showed a rapidly progressive IgAN with extensive crescentic lesions at histological evaluation.

In all of the four patients the onset of the disease was characterised by a compromised renal function, thought, according to the medical history, in patients 2 and 4 clinical signs of nephropathy had started some months before the first medical evaluation.

This detail, considering the poorer clinical outcome of patients 2 and 4 (table 1), strongly highlights the need of promptness in the treatment of these conditions.

Patient 1 achieved a complete remission after steroid pulse therapy (Pozzi scheme), while for patients 2,3,4 an additional immunosuppressive treatment was required.

The nephropathy of patient 5 was, instead, characterized by AKI with consistent macrohaematuria. Interestingly, the severity of the clinical presentation was not related to the glomerular lesion (the histology showed a minimal change disease), rather to the intra-tubular haemorrhage, causing an obstructive acute kidney injury. Patient 5 achieved a complete remission after steroid treatment.

The onset of IgAN in patients 6 and 7 was characterized by a nephrotic syndrome, which is a very uncommon feature (<2% of all IgAN).

Patient 6, who showed a massive proteinuria (till 11 grams/24 hours) was promptly treated with steroid and tacrolimus, achieving a complete remission in 6 moths.

Patient 7, a sri-lankan girl, was diagnosed in 2008 in Sri-Lanka.

She underwent treatment with steroid and Mycophenolate and successively, for the persistence of proteinuria, with Cyclosporine A.

From 2014 she has been followed by our centre. Despite a second cycle with Cyclosporine she has shown a persistence of proteinuria and a slow progression to CKD.

Conclusion

This study highlights that a typical disease like IgAN may hide behind an atypical and severe presentation.

Moreover, the blackboard of the atypical forms is extremely heterogeneous, stretching from NS to crescentic and progressive diseases.

As a consequence, the treatment of these conditions is not codified and represents an important challenge for the clinician.

This calls for multicentric studies which could provide shared recommendation for the management of these atypical forms of IgAN.

P0165HYPERTENSION IN OVERWEIGHT AND OBESE CHILDREN: IMPACT ASSESMENT OF ABPM PARAMETERS

Background and Aims

We describe the relationship between overweight and obesity and Hypertension on ABPM.

Method

We conducted a cross-sectional study using a database of patients aged 6-16 years, who had undergone 24h ABPM from December 2002 through December 2016. ABPM were performed using the validated device Spacelab 90217. Were evaluated the 24h MAP, daytime MAP, nocturnal MAP, systolic and diastolic load, MAP Systolic and Diastolic. Subjects were grouped by BMI Z-score into overweight (>1<2), obese (BMI Z-score >2<3) and severe obese (BMI Z-score >3). A total of 1016 patients were enrolled and recorded n.1210 ABPMs. Obese pts were 202 (19.8%); 126 M;76F;median age 10,2 y. Overweight childrens were 97 (11.9%);52 M;45F;median age 8,4y.

Results

Among overweight childrens (BMI Z-Score >1<2): 12 (12.3%) had hypertension, 22 (22.6%) pre-hypertension, 15 (15.4%) MH; non dipping pattern was recorded in 26 (52%). 48 were normotensive. Among obese childrens, 122 had hypertension (60.3%): 24 pts had Masked Hypertension (19.6%); 72 (59.0%) had severe ambulatory hypertension with BMI z-score >3 (mean 3.8) ,and in this category all pts were both systolic and diastolic non dipping. 32 (64%) obese with BMI z-score >2, <3 were non-dipping. Diastolic load was significantly higher (p>0,0001) in severe obese. 28 pts had ambulatory prehypertension (13.8%), 11 pts had White Coat Hypertension (4.9%).41 pts had normotension (20.2%).

Conclusion

The severity of ambulatory hypertension increased with increased BMI Z-score. The non-dipping status is associated, not only with higher BMI Z-score, but was present in overweight and obese with BMI z-score >2<3 also. ABPM is an effective tool that should become routine in all obese patient, but also in overweight childrens, which may lead to better treatments and prevention methods.

P1369ACUTE EXTRACORPOREAL DIALYSIS USING TWO-WAY PICC POWER INJECTABLE IN YOUNG CHILDREN

Background and Aims

Acute extracorporeal dialysis is a short treatment, performed by a central venous catheter of large size, ensuring high flow. These devices have limitations: high caliber, excessive length, impossibility of tunneling and exit-site location in the supraclavicular region, with a subsequent high risk of dislocation and contamination. The authors report a new approach to dialytic central venous catheters selection in children.

Method

From January 2013 to December 2017, 16 children weighing less than 15 kg needed acute extracorporeal dialysis. Patients received an ultrasound guided percutaneous implantation of a two-way PICC power injectable catheter, in the right internal jugular vein or in the anonymous right vein. The device size always respected the ratio of 1/3; the catheters were cut to be adapted to child height, and subclavear tunnelizations and stabilizations were ensured. The hemodialysis was performed with the Prismaflex Gambro system. The effectiveness of treatment was evaluated by recirculation test and by measuring the KT/Vat the third hour, expressing the dialysis adequacy.

Results

Two-way power injectable central venous catheter,sized from 5 to 7 Fr and long from 8 to 15 cm were used. The recorded blood flow ranged from 4.7ml/min/kg to 7ml/min/kg; a KT/V variable from 0.5 to 1 was detected; the recycling rate was between 32% and 40%. No catheter related complications were observed.

Conclusion

In children weighing less than 15 kg, PICC power injectable have lower blood flow and higher recirculation rate compared to traditional dialysis catheters. However, the dialytic adequacy was suitable for an acute hemodialysis treatment. In addition, these catheters are available in a wide range of calibers and result more adaptable to the venous system of younger children.

P1831ABPM DIFFERENCE BETWEEN OBESE AND NON OVERWEIGHT HYPERTENSIVE CHILDREN

Background and Aims

The goal of our study was to analyze the difference in ABPM pattern in overweight and non overweight hypertensive children

Method

The ABPM were performed using Spacelab 90207 and recorded over 24h.Readings were taken every 15 minutes while awake,and every 20 minutes while asleep. In both groups were evaluated the 24h MAP,daytime MAP,nocturnal MAP, systolic and diastolic load,mean 24h SBP and DBP.

A total of 108 pts were enrolled. Pts were divided in two groups.In the first group 54 pts non overweight with primary hypertension:33 male and 21 female with mean age of 10.4 y. In the second group the obese hypertensive children, with mean age of 10.5 y, were divided into two subgroups according to BMI Z-scores:subgroup 1 BMI Z-score >2<3 n 40 pts (17 f;21m); subgroup 2 BMI Z-score >3 n (4f;10m).

Results

Systolic load was significantly higher in obese group (p 0,0409).In obese group n.12 were dipper (22,2%).Obese with BMI zscore >3 was all non dipper (n14 ;100%). In the lean group n 26 was dipper (48.1%),and 28 (51.8%) non dipper. 24 h MAP, Systolic and Diastolic load were significantly higher (p 0,0001) in the obese with BMI z score >3 compared to the lean group.

Conclusion

The statistically significant pathological pattern among obese is the increase inmean PAS and systolic load, as well as the absence of night dipping in severe obese. The increase in systolic load is already evident in obese mild.This gives a significant predictive value of cardiovascular damage to ABPM which increases with the severity of obesity worse.

Oral Sucrosomial® iron versus intravenous iron for recovering iron deficiency anaemia in ND-CKD patients: a cost- minimization analysis

BACKGROUND

Oral iron is recommended as first line treatment of anemia in non-dialysis chronic kidney disease (ND-CKD) patients. Sucrosomial® iron, a new generation oral iron with high absorption and bioavailability and a low incidence of side effects, has shown to be not inferior to intravenous (IV) iron in the replacement of iron deficiency anemia in patients with ND-CKD. Besides the clinical benefit, it is also important to determine the comparative total costs of oral versus IV iron administrations. The aim of this study was to perform a cost-minimization analysis of oral Sucrosomial iron, compared with IV iron gluconate from an Italian societal perspective.

METHODS

Cost analysis was performed on the 99 patients with ND-CKD and iron-deficiency anemia of the randomized trial by Pisani et al. Human and material resources utilization was recorded during each iron administration. According to study perspective, direct and indirect costs were considered. Costs for each resource unit were taken from official Italian sources. Probabilistic sensitivity analyses were carried out to test the robustness of the results.

RESULTS

The base case analysis showed an average cost/cycle per patient of € 111 for oral iron and € 1302 for IV iron. Thus, the potential saving was equal to € 1191 per patient/cycle. The sensitivity analysis showed that the most sensitive driver is the time loss by patient and caregivers for the therapy and related-care, followed by the minutes of nursing care and the number of kilometres travelled to reach the referral centre.

DISCUSSION

This study showed that oral Sucrosomial® iron could offer specific advantages in terms of potential savings, and allowed identifying some implications for future research. Such advantages still persist with the new single dose IV iron formulation available in the market, although to a lesser extent.

Idiosyncratic hepatic toxicity in autosomal dominant polycystic kidney disease (ADPKD) patient in combined treatment with tolvaptan and amoxicillin/clavulanic acid: a case report

Background

Autosomal dominant polycystic kidney disease (ADPKD) is a hereditary disease characterized by the presence of renal cysts. Over time the expanding cysts lead to progressive renal failure. The use of tolvaptan, a V₂-receptor antagonist, was recently approved in ADPKD patients. It was demonstrated that tolvaptan get slower decline in Kidney function compared with placebo. Idiosyncratic hepatic toxicity was described in patients receiving tolvaptan, with elevations in aminotransferases levels. We describe the first case reported in the literature in which hepatic toxicity is caused by the association of amoxicillin/clavulanic acid and tolvaptan.

Case presentation

A 41 years old woman with diagnosis of ADPKD had been in treatment with tolvaptan for 16 weeks when an elevation of liver enzyme levels was detected. She had taken autonomously amoxicillin/clavulanic acid (in doses of 825/175 mg twice a day for 7 days) about 5 weeks before.

The timing of the event and the kind of hepatocellular injury could be attributed to the concomitance of medication of tolvaptan and amoxicillin/clavulanic acid.

Conclusion

We highlight the need to careful monitor hepatic enzyme levels in order to recognize early hepatic side effects in ADPKD patients in treatment with tolvaptan and amoxicillin/clavulanic acid.

Glomerular Hyperfiltration: An Early Marker of Nephropathy in Fabry Disease

BACKGROUND AND OBJECTIVES

Progressive nephropathy is one of the main features of Fabry disease (FD). It has been supposed that an early phase, clinically silent disease occurs in childhood and adolescence and is characterized by glomerular hyperfiltration (HF). Surprisingly, although HF has been reported in several studies, its prevalence is at present unknown. The focus of our study was to determine the prevalence of HF in a cohort of patients with FD and to identify the factors associated with a high risk of HF.

METHODS

To address this issue, a retrospective observational study of 87 patients with genetically confirmed FD was performed. HF was defined as an estimated glomerular filtration rate (eGFR) > 130 mL/min/1.73 m2 corrected for age (> 40 years: -1 mL/min/1.73 m2/year).

RESULTS

HF occurred in 21 patients (24% of our population), and increased to 50% when only young adults were considered. Hyperfiltrating patients were younger and had lower proteinuria levels than those without HF. The prevalence of cardiovascular and other manifestations of FD was significantly lower in hyperfiltering patients.

CONCLUSIONS

Our study showed a negative correlation between eGFR and age, and with proteinuria levels and the presence of cardiovascular and other manifestations of FD. These data favor the view that HF in Fabry patients could be related predominantly to a predisease state. Even in the absence of a "measured" GFR, HF should be regarded as an early marker of Fabry nephropathy, and its recognition and confirmation by true GFR seems a relevant feature to address the issue of the potential benefit of nephroprotective treatments at the early stage of Fabry nephropathy.