It is generally believed that infants are more susceptible to development of renal scarring after pyelonephritis than children over 5 years old. This view has led to differences in investigations and treatment according to age. The aim of this prospective study was to assess the occurrence of renal parenchymal lesion in children over 5 years admitted with a first-time symptomatic urinary tract infection (UTI). Between October 2000 and April 2002, 52 children aged over 5 years who were admitted to our department with probable acute pyelonephritis (APN) and a positive urine culture were included in this study. All children received antibiotics for 14 days. During the acute phase of infection, scintigraphy with technetium-99m-labeled dimercaptosuccinic acid (DMSA) and ultrasonography (US) were done. Voiding cystourethrography (VCUG) was performed in all children early in the course of the illness, generally within 5-7 days of hospitalization. When scintigraphy showed renal parenchymal changes, repeat scintigraphy was done after at least 3 months to assess the progression of renal abnormalities. Of the 52 children with a first-time documented pyelonephritis, cortical scintigraphy showed renal lesion in 41 children (78.8%). US was normal in all children with normal renal scintigraphy, while it detected renal abnormalities in 16 of the 41 (39 %) with abnormal scintigraphy (p <0.0001). Topographic analysis of the 165 focal lesions showed that 42.4% were localized to the upper poles, 17.5% to the middle third, and 40% to the lower poles of the kidneys. Repeat scintigraphy showed persistent lesions corresponding to those on the initial scan in nine (28.2%) of the 32 children. Renal lesions had partly regressed in 23 (71.8%) of the patients who underwent repeat scintigraphy. Vesicoureteral reflux was observed in 13.4% of kidneys and renal parenchymal abnormalities were identified in 71.4% and 72.2% of renal units, respectively, with and without reflux ( p >0.05). In conclusion, our data did not confirm the conventional opinion that the risk of renal scarring after pyelonephritis is low in children over the age of 5 years. Our findings suggest that renal scintigraphy may be a more appropriate method of investigation than VCUG for evaluation of the children over 5 years with acute pyelonephritis. Additionally, the frequency of scintigraphic changes is high, and a strategy based exclusively on ultrasound findings would miss about 61% of the abnormal renal units. We recommend that all children, irrespective of age, will benefit from further investigations that might prevent or limit the development of scarring process and renal complications.

BackgroundThere is still an ongoing discussion on the prognostic value of cystatin C in assessment of kidney function. Accordingly, the present study aimed to conduct a meta-analysis to provide evidence for the prognostic value of this biomarker for acute kidney injury (AKI) in children.MethodsAn extensive search was performed in electronic databases of Medline, Embase, ISI Web of Science, Cochrane library and Scopus until the end of 2015. Standardized mean difference (SMD) with a 95% of confidence interval (95% CI) and the prognostic performance characteristics of cystatin C in prediction of AKI were assessed. Analyses were stratified based on the sample in which the level of cystatin C was measured (serum vs. urine).ResultsA total of 24 articles were included in the meta-analysis [1948 children (1302 non-AKI children and 645 AKI cases)]. Serum (SMD = 0.96; 95% CI: 0.68-1.24; p < 0.0001) and urine (SMD = 0.54; 95% CI:0.34-0.75; p < 0.0001) levels of cystatin C were significantly higher in children with AKI. Overall area under the curve of serum cystatin C and urine cystatin C in prediction of AKI were 0.83 (95% CI: 0.80-0.86) and 0.85 (95% CI: 0.81-0.88), respectively. The best sensitivity (value = 0.85; 95% CI: 0.78-0.90) and specificity (value = 0.61; 95% CI: 0.48-0.73), were observed for the serum concentration of this protein and in the cut-off points between 0.4-1.0 mg/L.ConclusionThe findings of the present study showed that cystatin C has an acceptable prognostic value for prediction of AKI in children. Since the serum level of cystatin C rises within the first 24 h of admission in patients with AKI, this biomarker can be a suitable alternative for traditional diagnostic measures.

Our results identify that the sensitivity of serum CysC for detecting AKI is higher than that of serum Cr in a heterogeneous pediatric intensive care unit (PICU) population.

Urolithiasis is relatively common in children, and identifiable predisposing factors for stone formation, including metabolic and structural derangements, can be established in most cases. Vesicoureteral reflux (VUR) is a common cause of kidney stone formation. The pathophysiological mechanism of urolithiasis in reflux is related to urinary tract infection and urinary stasis, both of which promote urinary crystal formation, but metabolic causes, such as crystallurias (mostly hypercalciuria), may also be involved in this process. However, few studies on urinary calcium and uric acid excretion in children with VUR have been conducted. We have studied the frequency of hypercalciuria and hyperuricosuria in children with VUR and compared the results with those from a control group. The VUR group comprised 108 children with VUR (19 boys, 89 girls; age range 3 months to 12 years), and the control group comprised 110 healthy children without any history of reflux or urinary tract infection (30 boys, 80 girls; age range 2 months to 12 years). Fasting urine was analyzed for the calcium/creatinine (Ca/Cr) and uric acid/creatinine (UA/Cr) ratios. Hypercalciuria was more frequently diagnosed in the VUR patients than in the control group (21.3 vs. 3.6%; P = 0.0001). Significant differences between the two groups were also found for the mean Ca/Cr and UA/Cr ratios (P = 0.0001 and P = 0.0001, respectively). No differences were found in the urinary Ca/Cr or UA/Cr ratios related to VUR grading or unilateral/bilateral VUR in the patient group, with the exception of those for hypercalciuria and mild VUR (P = 0.03). The association of urinary stones and microlithiasis in the VUR group was 29.6%. Our results demonstrate that the frequency of hypercalciuria and hyperuricosuria was higher in pediatric patients with VUR than in healthy children. Knowing this relationship, preventive and therapeutic interventions for stone formation in VUR could be greatly expanded.

The incidence of vesicoureteral reflux (VUR) in the general population is less than 1%, but it is high in families with reflux. The reported prevalence of VUR among siblings of index patients with reflux has ranged from 4.7% to 51%. Reflux carries an increased risk of pyelonephritis and long-term renal impairment. The purpose of this study was to identify the age-related incidence and severity of reflux, and the frequency of associated renal parenchymal damage in siblings of children with reflux in order to assess the use of screening at different ages. Between October 1994 and February 2003, 40 siblings of 34 index patients were screened with direct voiding cystography. 99( m ) technetium (Tc)-dimercaptosuccinic acid (DMSA) nuclear renal scans were performed in siblings with VUR to detect renal scarring. The cystograms were interpreted as showing the presence or absence of VUR and the DMSA scan as symmetrical or asymmetrical differential function, with or without renal scarring. Of 40 siblings, 17 had VUR, representing an incidence of 42.5%. The mean age at study entry of the 15 boys and 25 girls was 63 months (range 6 months to 12 years). The majority of siblings with abnormal DMSA scans were asymptomatic. Reflux was unilateral in 12 siblings and bilateral in 5. Of the 17 refluxing siblings (22 refluxing ureters), 7 (41.17%) had a history of symptomatic urinary tract infection (UTI). The frequency of VUR was nearly equal in siblings over 6 years and those younger than 6 years. Of the 17 siblings with VUR, 16 had DMSA scintigraphy. Of these, 5 were normal and 11 (68.75%) showed abnormalities (7 asymmetrical differential function and 4 parenchymal defect), which was bilateral in 7 and unilateral in 4. In conclusion, this study confirms a significant overall incidence of VUR and renal parenchymal damage in the siblings of patients with known reflux. The prevalence of reflux in older siblings is similar to that in younger siblings. Our review suggests that all siblings over 6 years should undergo a screening cystogram, even in the absence of urinary tract infection. DMSA scintigraphy of asymptomatic siblings appears to be beneficial in preventing renal injury.

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Chronic hemodialysis may lead to abnormalities in the serum levels of some trace elements in children with CRF that increase in severity with increasing duration of hemodialysis. Deficiencies of these trace elements--zinc in particular--may contribute to various conditions and symptoms in children undergoing chronic hemodialysis.

To construct reference percentiles for blood pressure (BP) by sex, age and height for the first time in Iran, we used data on 16 972 healthy children, aged 1 month to 18 years, collected during 2000-2010 in Tehran. BP in this population rose steadily with age and height following a very similar trend in both genders up to the age of 14. Systolic BP (SBP) rise was more prominent in younger ages, and after puberty (15-18 years) was greater in boys compared with girls, while the rise in diastolic BP (DBP) was slightly higher in girls. Iranian norms, compared with 'Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents' (US-4th-Report) and the 'German BP Percentiles by Age and Height for Children and Adolescents' (KiGGS), showed a similar pattern of differences for both genders. For example, for Tehrani boys up to 6 years old whose heights were equal to 50th percentile of stature-for-age as well as length-for-age growth charts, the differences in 95th percentile for SBPs compared with the US-4th-report varied from 2-21 mm Hg while compared with KiGGS, maximum of differences was 9 mm Hg. For boys 7-15 years of age, ours were slightly higher than both. For ages of 16 and 17 years, we yielded figures lower than US-4th-report (2 mm Hg) but higher than KiGGS (3 mm Hg). Iranian 95th percentile for DBPs was lower than US-4th-report and KiGGS (1-11 mm Hg). Considering the differences with US-4th-report and KiGSS standards, the references presented in this study should rather be applied in Iranian population.