Constantinos J. Stefanidis

Association of Procalcitonin With Acute Pyelonephritis and Renal Scars in Pediatric UTI

BACKGROUND AND OBJECTIVE: Urinary tract infections (UTIs) are common childhood bacterial infections that may involve renal parenchymal infection (acute pyelonephritis [APN]) followed by late scarring. Prompt, high-quality diagnosis of APN and later identification of children with scarring are important for preventing future complications. Examination via dimercaptosuccinic acid scanning is the current clinical gold standard but is not routinely performed. A more accessible assay could therefore prove useful. Our goal was to study procalcitonin as a predictor for both APN and scarring in children with UTI. METHODS: A systematic review and meta-analysis of individual patient data were performed; all data were gathered from children with UTIs who had undergone both procalcitonin measurement and dimercaptosuccinic acid scanning. RESULTS: A total of 1011 patients (APN in 60.6%, late scarring in 25.7%) were included from 18 studies. Procalcitonin as a continuous, class, and binary variable was associated with APN and scarring (P < .001) and demonstrated a significantly higher (P < .05) area under the receiver operating characteristic curve than either C-reactive protein or white blood cell count for both pathologies. Procalcitonin ≥0.5 ng/mL yielded an adjusted odds ratio of 7.9 (95% confidence interval [CI]: 5.8–10.9) with 71% sensitivity (95% CI: 67–74) and 72% specificity (95% CI: 67–76) for APN. Procalcitonin ≥0.5 ng/mL was significantly associated with late scarring (adjusted odds ratio: 3.4 [95% CI: 2.1–5.7]) with 79% sensitivity (95% CI: 71–85) and 50% specificity (95% CI: 45–54). CONCLUSIONS: Procalcitonin was a more robust predictor compared with C-reactive protein or white blood cell count for selectively identifying children who had APN during the early stages of UTI, as well as those with late scarring.

Procalcitonin is a Predictor for High-Grade Vesicoureteral Reflux in Children: Meta-Analysis of Individual Patient Data

OBJECTIVE To assess the predictive value of procalcitonin, a serum inflammatory marker, in the identification of children with first urinary tract infection (UTI) who might have high-grade (≥3) vesicoureteral reflux (VUR). STUDY DESIGN We conducted a meta-analysis of individual data, including all series of children aged 1 month to 4 years with a first UTI, a procalcitonin (PCT) level measurement, cystograms, and an early dimercaptosuccinic acid scan. RESULTS Of the 152 relevant identified articles, 12 studies representing 526 patients (10% with VUR ≥3) were included. PCT level was associated with VUR ≥3 as a continuous (P = .001), and as a binary variable, with a 0.5 ng/mL preferred threshold (adjusted OR, 2.5; 95% CI, 1.1 to 5.4). The sensitivity of PCT ≥0.5 ng/mL was 83% (95% CI, 71 to 91) with 43% specificity rate (95% CI, 38 to 47). In the subgroup of children with a positive results on dimercaptosuccinic acid scan, PCT ≥0.5 ng/mL was also associated with high-grade VUR (adjusted OR, 4.8; 95% CI, 1.3 to 17.6). CONCLUSIONS We confirmed that PCT is a sensitive and validated predictor strongly associated with VUR ≥3, regardless of the presence of early renal parenchymal involvement in children with a first UTI.

Mutational analysis of the PLCE1 gene in steroid resistant nephrotic syndrome

Background Mutations in the PLCE1 gene encoding phospholipase C epsilon 1 (PLCɛ1) have been recently described in patients with early onset nephrotic syndrome (NS) and diffuse mesangial sclerosis (DMS). In addition, two cases of PLCE1 mutations associated with focal segmental glomerulosclerosis (FSGS) and later NS onset have been reported. Method In order to better assess the spectrum of phenotypes associated with PLCE1 mutations, mutational analysis was performed in a worldwide cohort of 139 patients (95 familial cases belonging to 68 families and 44 sporadic cases) with steroid resistant NS presenting at a median age of 23.0 months (range 0–373). Results Homozygous or compound heterozygous mutations were identified in 33% (8/24) of DMS cases. PLCE1 mutations were found in 8% (6/78) of FSGS cases without NPHS2 mutations. Nine were novel mutations. No clear genotype–phenotype correlation was observed, with either truncating or missense mutations detected in both DMS and FSGS, and leading to a similar renal evolution. Surprisingly, three unaffected and unrelated individuals were also found to carry the homozygous mutations identified in their respective families. Conclusion PLCE1 is a major gene of DMS and is mutated in a non-negligible proportion of FSGS cases without NPHS2 mutations. Although additional variants in 19 candidate genes (16 other PLC genes, BRAF,IQGAP1 and NPHS1) were not identified, it is speculated that other modifier genes or environmental factors may play a role in the renal phenotype variability observed in individuals bearing PLCE1 mutations. This observation needs to be considered in the genetic counselling offered to patients.

Home blood pressure monitoring in children and adolescents: a systematic review.

Objective As in the adults, in children and adolescents with elevated blood pressure (BP), the conventional office BP measurements might lead to incorrect diagnosis. Therefore, out-of-office BP measurements are often needed. Several studies have demonstrated the value of ambulatory BP (ABP) monitoring in pediatric hypertension, whereas home BP (HBP) monitoring has only recently been evaluated. Methods A systematic review of the evidence on HBP monitoring in children and adolescents has been performed (Medline/PubMed, Embase and Cochrane Library). Results A total of 27 studies (19 original study reports, two surveys, three guidelines documents, two reviews and one letter) were identified. These data suggest that by using electronic arm devices, reliable HBP readings are obtained. Unfortunately, very few electronic devices have been successfully validated in children. The reproducibility of HBP in children appears to be superior to office and similar to ABP measurements. Three-day-HBP monitoring with duplicate morning and evening measurements is the minimum schedule required, yet 6–7-day monitoring is recommended. HBP in children and adolescents is lower than daytime ABP, whereas no such difference exists in the adults. A school-based study in 778 children and adolescents provided the first HBP normalcy data. HBP has similar diagnostic value in children as in the adults and appears to be a reliable alternative to ABP monitoring in the detection of white-coat hypertension. Conclusion HBP monitoring appears to have considerable potential in pediatric hypertension. More research is needed on the clinical application of this method in children and adolescents.

Clinical practice recommendations for the care of infants with stage 5 chronic kidney disease (CKD5)

BackgroundTo provide recommendations for the care of infants with stage 5 chronic kidney disease (CKD5).SettingEuropean Paediatric Dialysis Working Group.Data SourcesLiterature on clinical studies involving infants with CKD5 (end stage renal failure) and consensus discussions within the group.RecommendationsThere has been an important change in attitudes towards offering RRT (renal replacement therapy) to both newborns and infants as data have accumulated on their improved survival and long-term outcomes. The management of this challenging group of patients differs in a number of ways from that of older children. The authors have summarised the basic recommendations for treating infants with CKD5 in order to support the multidisciplinary teams who endeavour on this difficult task.

Successful treatment of steroid-resistant nephrotic syndrome associated with WT1 mutations

The Wilms’ tumor suppressor gene 1 (WT1) encodes a transcription factor involved in kidney and gonadal development. WT1 is also a key regulator of podocyte functions and mutations have been found in a small percentage of children with isolated or syndromal steroid-resistant nephrotic syndrome. It is commonly assumed that the nephrotic syndrome (NS) in patients with WT1 mutations is unresponsive to therapy and characterized by rapid progression to end-stage renal disease. We report long-term observations in 3 children with focal–segmental glomerulosclerosis associated with WT1 mutations and NS (2 cases) or nephrotic range proteinuria (1 case). All patients showed a favorable response to an intensified therapy consisting of cyclosporin A (CyA) in combination with induction therapy with intravenous and oral prednisone. Treatment with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers was added to the regimen at various times. As shown both by the short-term response and during long-term follow-up, this treatment resulted in clinical remission of the NS and/or significant reduction of proteinuria, while normal renal function could be maintained over many years. Thus, glomerular diseases in selected patients with mutations in genes regulating renal development and podocyte function may respond to combination therapy with CyA and corticosteroids.

Imaging strategies for vesicoureteral reflux diagnosis

The prevalence of vesicoureteral reflux (VUR), although reported to be low in the general population, is high in children with urinary tract infection (UTI), first degree relatives of patients with known VUR and children with antenatal hydronephrosis. In addition, it has been shown that VUR and UTIs are associated with renal scarring, predisposing to serious long-term complications, i.e., hypertension, chronic renal insufficiency and complications of pregnancy. Therefore, diagnostic imaging for the detection of VUR in the high-risk groups of children has been a standard practice. However, none of these associations has been validated with controlled studies, and recently the value of identifying VUR after a symptomatic UTI has been questioned. In addition, several studies have shown that renal damage may occur in the absence of VUR. On the other hand, some patients, mainly males, may have primary renal damage, associated with high-grade VUR, without UTI. Recently, increasing skepticism has been noted concerning how and for whom it is important to investigate for VUR. It has been suggested that the absence of renal lesions after the first UTI in children may rule out VUR of clinical significance and reinforces the redundancy of invasive diagnostic techniques. Therefore, the priority of imaging strategies should focus on early identification of renal lesions to prevent further deterioration.

The importance of rare diseases: from the gene to society

What exactly do we mean by a rare disease (RD), and why are they important for paediatricians? The definition used for public health purposes in Europe is that an RD is one which affects fewer than one citizen in 2000; in the USA it is fewer than one in 1250.1 There are estimated to be between 6000 and 8000 known RDs in the world, many of which are predominantly paediatric disorders. About 75% of the diseases meeting the criteria for RD affect children, and about 30% of all patients with RDs die before their fifth birthday.2 Approximately 80% of RDs have a defined genetic basis.2 The true incidence and prevalence of individual RDs are often unclear. When the condition is fatal in childhood or early adult life, the prevalence in the population (table 1) will be well below the birth incidence, and will not reflect the gene frequency. Thus, to take the familiar example of cystic fibrosis, the birth incidence in the UK is about one in 2500 live births, but the population prevalence is given as about one in 8000. View this table: Table 1 Some examples of estimated European population prevalence given on the Orphanet website (http://www.orpha.net)5 Although individually rare, the cumulative burden of RDs is significant. RDs may affect as many as 30 million Europeans, with at least 3 million in the UK and 4 million in Germany, and this statistic has not been lost on the European Union (EU). A Committee of experts on rare diseases (EUCERD) was set up in November 2009 to assist and advise the European Commission, including, inter alia, drawing …

Office and out-of-office blood pressure measurement in children and adolescents.

Office and out-of-office blood pressure measurements are being used for the diagnosis of hypertension in children and adolescents. The US National Heart, Lung, and Blood Institute have recently presented a new classification of blood pressure. On the basis of office measurements the 90th, 95th and 99th percentile for gender, age and height are used to classify children and adolescents as normotensive, pre-hypertensive and stage-1 or stage-2 hypertensive. Although auscultation using a standard mercury sphygmomanometer remains the recommended method, accumulating evidence suggests that ambulatory blood pressure monitoring is useful for the detection of white-coat hypertension and the prediction of target organ damage in children and adolescents. Studies have shown ambulatory blood pressure to be more reproducible than office measurements and normative tables for ambulatory measurements have been developed from cross-sectional studies in children and adolescents. In regard to home measurements in children, there are limited data from small trials showing lower blood pressure levels than daytime ambulatory blood pressure. In conclusion, ambulatory blood pressure monitoring is already finding a role as a supplementary source of information in children and adolescents, whereas at present home measurements should not be used for decision making in this population.

Serum osteoprotegerin, RANKL and fibroblast growth factor-23 in children with chronic kidney disease

Osteoprotegerin (OPG), receptor activator of the nuclear factor κB ligand (RANKL) and fibroblast growth factor-23 (FGF-23) play a central role in renal osteodystrophy. We evaluated OPG/RANKL and FGF-23 levels in 51 children with chronic kidney disease (CKD) [n = 26 stage 3 or 4 (CKD3–4) and n = 25 stage 5 (CKD5)] and 61 controls. Any possible association with intact parathyroid hormone (iPTH) and bone turnover markers was also investigated. The OPG levels were lower in the CKD3–4 group (p < 0.001) and higher in the CKD5 group (p < 0.01) than in the controls, while RANKL levels did not differ. The FGF-23 levels were higher in both patient groups (p < 0.0001), while the levels of phosphate and iPTH were higher only in the CKD5 group (p < 0.0001). There were independent positive correlations between OPG and RANKL (β = 0.297, p < 0.01) and FGF-23 (β = 0.352, p < 0.05) and a negative correlation with the bone resorption marker TRAP5b (β = −0.519, p < 0.001). OPG was positively correlated with iPTH (R = 0.391, p < 0.01). An independent positive correlation between FGF-23 and phosphate (β = 0.368, p < 0.05) or iPTH (β = 0.812, p < 0.0001) was noted. In conclusion, we found that higher OPG levels in patients with CKD stage 5 correlated with the levels of RANKL, FGF-23, iPTH, and TRAP5b. These findings may reflect a compensatory mechanism to the negative balance of bone turnover. High FGF-23 levels in early CKD stages may indicate the need for intervention to manage serum phosphate (Pi) levels.