Childhood stones

Management of an Intraparenchymal Struvite Stone Using Laparoscopic Nephrolithotomy: A Case Report

This study aims to present a case of laparoscopic nephrolithotomy and highlight its successful outcome. The patient was a 65-year-old male who experienced intermittent colicky flank pain. Imaging revealed the presence of a 20-mm round-shaped stone in a hydronephrotic calyx located in the mid-pole of the left kidney, possibly with a parenchymal component. Given the stone's location, neither percutaneous nephrolithotripsy (PCNL) nor ureterorenoscopy (URS) was considered feasible. The findings of this study demonstrate the effectiveness and suitability of laparoscopic nephrolithotomy (LNL) in managing stones. It emphasizes that LNL can be utilized not only as an alternative treatment but also as a viable initial option when appropriate case selection is made.

Analysis of urine composition from split 24-h samples: use of 12-h overnight samples to evaluate risk factors for calcium stones in healthy and stone-forming children

INTRODUCTION

The analysis of 24-h urine is the gold standard to diagnose metabolic abnormalities in the stone-forming patient. However, urinary composition changes throughout the day and analyzing the whole 24-h urine may mask peaks of increased risk of crystallization.

OBJECTIVE

To examine variations of stone-promoting and stone-inhibiting factors in urine using split 24-h samples from healthy and stone-forming children.

STUDY DESIGN

Urine was collected from 87 healthy and 26 stone-forming children using a split collection procedure (12-h daytime urine and 12-h overnight urine). Urine volume, pH, calcium (Ca), magnesium (Mg), phosphate (P), citrate (Cit), uric acid (Ur), and oxalate (Ox) were determined, and the Ca/Cit ratio was calculated.

RESULTS

The overnight urine samples in both groups had higher levels of P and Mg, lower volume, lower pH, and less citrate and uric acid. As can be seen in the table, higher percentages of healthy and stone-forming children had altered 12-h night urine than 24-h urine with regards to Ca/Cr, Cit/Cr and Ca/Cit ratios. All healthy subjects and all stone-forming children (except one) with altered Cit/Cr ratios or Ca/Cit ratios in the 24-h sample also had altered ratios in the 12-h overnight sample.

DISCUSSION

This study indicates that urine composition changes throughout the day, and that there is daily variability in most of the parameters related to kidney stone formation. Furthermore, 12-h overnight samples seem to be more sensitive than 24-h samples in detecting the most common urinary abnormalities. The main limitation of this study is the relative low sample size of stone-forming children, owing to the low prevalence of nephrolithiasis in childhood.

CONCLUSIONS

We observed a higher excretion of stone-promoting substances and a lower citrate in urine at night. However, the study results do not provide enough evidence to conclude that the use of a 12-h overnight sample collection can replace 24 h urine analysis in the metabolic evaluation of children with lithiasis.

The Modern Metabolic Stone Evaluation in Children

OBJECTIVE

To evaluate metabolic abnormalities in a contemporary pediatric population after their first stone episode. The incidence of pediatric nephrolithiasis is increasing and therefore the etiologies contributing to today's pediatric stone formation may also be changing.

MATERIALS AND METHODS

A retrospective review of all consecutive children presenting after their first kidney stone between 2000 and 2014 was performed. We compared demographic data, serum chemistry results, and 24-hour urine results and treatments.

RESULTS

One hundred thirteen children with a mean age of 11 years (5 months to 18 years) who presented with their first kidney stone episode between 2000 and 2014 were evaluated. Sixteen patients (14%) were found to have an underlying genetic or systemic disease. Overall, there was a low rate of serum chemistry abnormalities. The most common abnormalities found within the 24-hour urine evaluation included low urine volume (89%) and hypocitraturia (68%). Hypercalciuria occurred rarely (11%).

CONCLUSION

We identified a low rate of underlying genetic or systemic diseases contributing to modern pediatric stone presentation and an increased proportion of idiopathic stones. Our study differs from historical findings by identifying a low rate of hypercalciuria and a high rate of low urine volume and hypocitraturia, suggestive of changing metabolic abnormalities contributing to modern pediatric stone disease.

Risk factors evaluation for urolithiasis among children

BACKGROUND

The prevalence of pediatric urolithiasis varies from 0.01-0.03%. Urolithiasis may be caused by anatomical, metabolic and environmental factors. Recurrence varies between 16 to 67%, and it is frequently associated with metabolic abnormalities. The objective of the present work was the identification of risk factors that promote urolithiasis in a child population.

METHODS

This study included 162 children with urolithiasis and normal renal function (mean age 7.5 years). Risk factors were investigated in two stages. In the first stage, 24-hour urine, and blood samples were analyzed to assess metabolic parameters and urinary tract infection. During the second stage, the effect of calcium restriction and a calcium load on renal Ca excretion were evaluated. Data were statistically analyzed.

RESULTS

Urolithiasis was observed in 0.02% of children, 50% of them with family history of urinary stones. There were multiple risk factors for urolithiasis including hypocitraturia (70%), hypomagnesuria (42%), hypercalciuria (37%; in 11/102 was by intestinal hyperabsorption, in 13/102 was unclassified. Ca resorption or renal Ca leak were not detected). We also detected alkaline urine (21%), systemic metabolic acidosis (20%), urinary infections (16%), nephrocalcinosis with urolithiasis (11%), oliguria (8%), urinary tract anomalies, hyperuricosemia and hypermagnesemia (7% each one), hypercalcemia (6%), hyperoxaluria (2%) and hypercystinuria (0.61%).

CONCLUSIONS

Hypocitraturia and hypomagnesuria were the most frequent risk factors associated with urolithiasis, followed by hypercalciuria. High PTH values were excluded. Children presented two or more risk factors for urolithiasis.

Urinary excretion of calcium, magnesium, phosphate, citrate, oxalate, and uric acid by healthy schoolchildren using a 12-h collection protocol

BACKGROUND

Improving knowledge about normal urine composition in children is important for early prevention of lithiasis. We describe urinary excretion values of calcium (Ca), magnesium (Mg), phosphate (P), citrate (Cit), uric acid (Ur), and oxalate (Ox) in healthy children with and without a family history of lithiasis, using a 12-h urine collection protocol.

METHODS

Urine samples were obtained from 184 children (5-12 years): a spot sample collected in the afternoon, and a 12-h overnight sample. Solute/creatinine (Cr) and 12-h solute excretion was calculated.

RESULTS

Urinary excretion values of the studied solutes are presented as percentile values, separately for each type of sample. Due to age-related differences in the solute/creatinine ratios, except for Ca and Cit, results are described according to the child's age. The presence of excretion values related to an increased risk of lithiasis was more common in children with a family history.

CONCLUSIONS

We report data from urine samples collected by using a simplified collection protocol. The observed differences between children with and without a family history of lithiasis could justify that in population studies aimed at setting reference values, the former are excluded.

Pediatric urolithiasis in a non-endemic country: a single center experience from The Netherlands

OBJECTIVE

To provide insight in causative factors of pediatric urolithiasis in The Netherlands, a non-endemic country.

PATIENTS AND METHODS

Data from 71 children with urolithiasis and stone analyses between 1996 and 2010 in the Radboud University Nijmegen Medical Centre were studied retrospectively. Patients (48 boys, 23 girls, ratio 2.1:1) were aged 0.5-18.3 years (mean 8.8, SD 5.6). All stone analyses were performed with FTIR spectroscopy.

RESULTS

Of the 49 patients with metabolic analysis, 78% showed one (n = 15) or more (n = 23) metabolic abnormalities. Forty-seven percent had hypercalciuria (n = 23), 31% had hyperoxaluria (n = 15), 29% hypocitraturia (n = 14), 10% hyperuricosuria (n = 5), 10% cystinuria (n = 5), and 6% had hypomagnesiuria (n = 3). Sixty-one percent of the stones were composed of calcium phosphate, calcium oxalate, or a combination of those. Twenty-six percent consisted of pure or mixed magnesium ammonium phosphate, 8.3% pure or mixed urate, and 8.3% cystine.

CONCLUSION

Children with urolithiasis in The Netherlands show stone composition similar to other Western European countries. However, a high percentage of metabolic abnormalities (78%) was found, indicating the need for extensive evaluation of pediatric urolithiasis to find underlying causes and thereby prevent stone recurrences. A close collaboration between a pediatric nephrologist and urologist is mandatory for optimal surgical and medical treatment.

[Urolithiasis in childhood]

Urinary stone disease is relatively rare in children with an overall incidence of 1-2 %; however, it is often associated with metabolic abnormalities that may lead to recurrent stone formation. Stone analysis and subsequent metabolic evaluation is therefore mandatory for this high-risk group after the first stone event. The objectives of stone management in children should be complete stone clearance, prevention of stone recurrence, preservation of renal function, control of urinary tract infections, correction of anatomical abnormalities and correction of the underlying metabolic disorders. The full range of minimally invasive procedures is available if active stone removal is necessary. The majority of stones in children can be managed either with extracorporeal shock wave lithotripsy which has a higher efficacy in children than in adults, percutaneous nephrolithotomy, ureterorenoscopy or a combination of these modalities while open or laparoscopic surgery is limited to well-selected cases with underlying anatomical abnormalities.

Risk factors for urinary stones in healthy schoolchildren with and without a family history of nephrolithiasis

BACKGROUND

The prevalence of lithiasis is increasing at all ages. This study aimed to assess the crystallization risk in urine from healthy school children and to determine urinary parameters that are most associated with it.

METHODS

Urine samples were obtained from 184 children aged 5-12 years: a spot sample collected in the afternoon, and a 12-h overnight sample. Information was obtained regarding family histories of lithiasis. Urine volume, pH, and biochemical parameters of stone risk were measured. Crystallization risk was defined by the presence of specific urine conditions that had previously been associated with stone formation in vitro.

RESULTS

Crystallization risk was observed in 15 % of spot urine samples and 54 % of 12-h samples. Metabolic abnormalities and a low urinary volume were more frequently detected in children with crystallization risk. Calcium excretion and calcium/citrate ratio were higher in children with a family history of lithiasis.

CONCLUSIONS

We observed a high prevalence of crystallization risk in urine, especially in children with a family history of the disease. Low urinary volume was the factor most associated with increased risk. Adequate fluid intake at an early age may be a simple and effective measure to reduce the incidence of nephrolithiasis.

Metabolic risk factors and the effect of metaphylaxis in pediatric stone disease with hypocitraturia

To describe the metabolic risk factors and investigate the effect of prophylaxis based on these factors on long-term recurrence of urolithiasis in pediatric patients with hypocitraturia. One-hundred and twenty-nine pediatric patients who underwent percutaneous nephrolithotomy between January 2008 and June 2011 were evaluated for metabolic risk factors. The patients with hypocitraturia were enrolled in this study and the data were analyzed using statistical methods for a mean period of 2 years for metabolic abnormalities, stone type, and the effect of potassium citrate prophylaxis on stone recurrence. A 24-h urine metabolite analysis revealed one or more metabolic risk factors in 115 (89.2 %) of the patients, whereas 14 (10.8 %) of the patients had no metabolic abnormalities. Eighty-two (63.5 %) of 129 patients had hypocitraturia. Of them, 43 (52 %) were male and 39 (48 %) were female, with a mean age of 9.7 ± 4.9 and 6.7 ± 4.4 (1-16) years, respectively(p = 0.102). Thirty-five (42.7 %) had pure hypocitraturia, and 47 (57.3 %) had two or more metabolic abnormalities. The most common dual metabolic abnormality was hypocitraturia and hypomagnesuria. Seventy-one patients (87 %) with hypocitraturia received medical prophylaxis and continued regularly, whereas 11 (13 %) patients did not receive medical prophylaxis despite being advised to do so. After a mean follow-up of 26.5 ± 9.4 months, the rate of recurrence was 1.4 % in the patients with hypocitraturia who continued prophylaxis and occurred in all of the patients who did not receive prophylaxis (p < 0.001). Calcium oxalate stones (95.2 %) were the most commonly found stones in the stone analysis. Detailed clinical and laboratory evaluations should be performed in children with urolithiasis. Appropriate prophylactic treatment as potassium citrate, should be given to prevent reformation of stones in patient with hypocitraturia.

A potential pathogenic role of oxalate in autism

BACKGROUND

Although autistic spectrum disorders (ASD) are a strongly genetic condition certain metabolic disturbances may contribute to clinical features. Metabolism of oxalate in children with ASD has not yet been studied.

AIM

The objective was to determine oxalate levels in plasma and urine in autistic children in relation to other urinary parameters.

METHOD

In this cross-sectional study, plasma oxalate (using enzymatic method with oxalate oxidase) and spontaneous urinary calcium oxalate (CaOx) crystallization (based on the Bonn-Risk-Index, BRI) were determined in 36 children and adolescents with ASD (26 boys, 10 girls) aged 2-18 years and compared with 60 healthy non-autistic children matched by age, gender and anthropometric traits.

RESULTS

Children with ASD demonstrated 3-fold greater plasma oxalate levels [5.60 (5th-95th percentile: 3.47-7.51)] compared with reference [(1.84 (5th-95th percentile: 0.50-4.70) μmol/L (p < 0.05)] and 2.5-fold greater urinary oxalate concentrations (p < 0.05). No differences between the two groups were found in urinary pH, citraturia, calciuria or adjusted CaOx crystallization rates based on BRI. Despite significant hyperoxaluria no evidence of kidney stone disease or lithogenic risk was observed in these individuals.

CONCLUSIONS

Hyperoxalemia and hyperoxaluria may be involved in the pathogenesis of ASD in children. Whether this is a result of impaired renal excretion or an extensive intestinal absorption, or both, or whether Ox may cross the blood brain barrier and disturb CNS function in the autistic children remains unclear. This appears to be the first report of plasma and urinary oxalate in childhood autism.

Influence of overweight on 24-hour urine chemistry studies and recurrent urolithiasis in children

Purpose

We investigated the influence of overweight on 24-hour urine chemistry studies and recurrent urolithiasis (UL) in children.

Materials and Methods

A retrospective cohort study was designed to assess children who presented with UL at a pediatric institution between 1985 and 2010. We calculated body mass index percentile (BMIp) adjusted for gender and age according to the 2007 Korean Children and Adolescents Growth Chart and stratified the children into 3 BMI categories: lower body weight (LBW, BMIp≤10), normal BW (NBW, 10<BMIp<85), and upper BW (UBW, BMIp≥85). Twenty-four hour urine chemistry studies (urine volume, creatinine, calcium, oxalate, citrate, and pH) were compared between the 3 BMIp groups. Univariate and multivariate analyses were performed to assess independent risk factors for stone recurrence.

Results

A total of 125 patients were included. The age of the patients in the NBW group was older than that of patients in the LBW group, but 24-hour urine chemistry studies did not differ significantly between the three groups. Mean urine citrate levels were lower (0.273±0.218 mg/mg/d vs. 0.429±0.299 mg/mg/d, p<0.05) and the incidence of hypocitraturia was higher (81.5% vs. 45.7%, p<0.05)) in the recurrent stone former group. In the univariate analysis, hypocitraturia and acidic urinary pH were risk factors, but in the multivariate analysis, only hypocitraturia was a risk factor for stone recurrence (hazard ratio, 3.647; 95% confidence interval, 1.047 to 12.703). In the Kaplan-Meier curve, the hypocitraturia group showed higher recurrence than did the normocitraturia group (p<0.05).

Conclusions

Unlike in adults, in children, overweight adjusted for gender and age was not associated with 24-hour urine chemistry studies and was not a risk factor for recurrent UL. Hypocitraturia was the only risk factor for UL in children.

The genetic components of idiopathic nephrolithiasis

Nephrolithiasis is a cause of significant morbidity and medical care expenses worldwide. Its prevalence has increased steadily during the last three decades among both adults and children. This trend suggests that changing environmental factors play a significant role in the risk of developing kidney stones although, conversely, there are many indications that genes play an important role in this condition as well. A limited number of monogenic forms have been identified, but the majority of nephrolithiasis cases are the result of complex, multi-factorial interactions between genetic inheritance and environmental exposure. Scientific evidence indicates that inheritance accounts for about half of the risk of common forms, making these forms suitable for investigation by genetic analysis. Here, we review the numerous studies that have been conducted to establish the role of genes in determining the risk of nephrolithiasis, the differential contribution of genes to this risk, and the confounding influence that environmental variables have on genetic studies.

History, epidemiology and regional diversities of urolithiasis

Archeological findings give profound evidence that humans have suffered from kidney and bladder stones for centuries. Bladder stones were more prevalent during older ages, but kidney stones became more prevalent during the past 100 years, at least in the more developed countries. Also, treatment options and conservative measures, as well as 'surgical' interventions have also been known for a long time. Our current preventive measures are definitively comparable to those of our predecessors. Stone removal, first lithotomy for bladder stones, followed by transurethral methods, was definitively painful and had severe side effects. Then, as now, the incidence of urolithiasis in a given population was dependent on the geographic area, racial distribution, socio-economic status and dietary habits. Changes in the latter factors during the past decades have affected the incidence and also the site and chemical composition of calculi, with calcium oxalate stones being now the most prevalent. Major differences in frequency of other constituents, particularly uric acid and struvite, reflect eating habits and infection risk factors specific to certain populations. Extensive epidemiological observations have emphasized the importance of nutritional factors in the pathogenesis of urolithiasis, and specific dietary advice is, nowadays, often the most appropriate for prevention and treatment of urolithiasis.

Genetic causes of hypercalciuric nephrolithiasis

Renal stone disease (nephrolithiasis) affects 3-5% of the population and is often associated with hypercalciuria. Hypercalciuric nephrolithiasis is a familial disorder in over 35% of patients and may occur as a monogenic disorder that is more likely to manifest itself in childhood. Studies of these monogenic forms of hypercalciuric nephrolithiasis in humans, e.g. Bartter syndrome, Dent's disease, autosomal dominant hypocalcemic hypercalciuria (ADHH), hypercalciuric nephrolithiasis with hypophosphatemia, and familial hypomagnesemia with hypercalciuria have helped to identify a number of transporters, channels and receptors that are involved in regulating the renal tubular reabsorption of calcium. Thus, Bartter syndrome, an autosomal disease, is caused by mutations of the bumetanide-sensitive Na-K-Cl (NKCC2) co-transporter, the renal outer-medullary potassium (ROMK) channel, the voltage-gated chloride channel, CLC-Kb, the CLC-Kb beta subunit, barttin, or the calcium-sensing receptor (CaSR). Dent's disease, an X-linked disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is due to mutations of the chloride/proton antiporter 5, CLC-5; ADHH is associated with activating mutations of the CaSR, which is a G-protein-coupled receptor; hypophosphatemic hypercalciuric nephrolithiasis associated with rickets is due to mutations in the type 2c sodium-phosphate co-transporter (NPT2c); and familial hypomagnesemia with hypercalciuria is due to mutations of paracellin-1, which is a member of the claudin family of membrane proteins that form the intercellular tight junction barrier in a variety of epithelia. These studies have provided valuable insights into the renal tubular pathways that regulate calcium reabsorption and predispose to hypercalciuria and nephrolithiasis.

Reference values of plasma oxalate in children and adolescents

Oxalate homeostasis is a derivative of absorption and transportation in the digestive system and renal/intestinal excretion of oxalate. The objective of this cross-sectional study was to determine normative values of plasma oxalate in relation to age, gender, and body size. A group of 1,260 healthy Caucasian children and adolescents aged 3 months to 18 years [mean +/- standard deviation (SD) 10.5 +/- 4.3] was studied. Each 1-year group comprised 70 subjects. Oxalate levels were assessed in blood plasma samples obtained from fasted individuals using the precipitation-enzymatic method with oxalate oxidase. Median oxalate levels in healthy infants was 3.20 micromol/L (5th-95th percentiles: 1.56-5.58) and was higher compared with older children [2.50 micromol/L (5th-95th percentiles: 0.95-5.74); p < 0.01]. No differences were found in plasma oxalate levels between boys and girls. There were no associations between plasma oxalate levels and anthropometric traits. In the healthy population aged 1-18 years, plasma oxalate concentration is independent of age, gender, and body size. Infants demonstrate higher plasma oxalate levels compared with older children, which suggests possible immature mechanisms of renal excretion. This study appears to be the first extensive report providing normative data for plasma oxalate in children and adolescents.

Nephrolithiasis

Kidney stones affect more than 5% of adults in the United States, and the prevalence is rising. The fundamental cause for all stones is supersaturation of urine with respect to the stone components; factors affecting solubility include urine volume, pH, and total solute excretion. Calcium stones are the most common in both adults and children and are associated with several metabolic disorders, the most common of which is idiopathic hypercalciuria. Therapy to prevent stones rests on lowering supersaturation, using both diet and medication. Effective treatment decreases stone recurrence and the need for procedures for stone removal.

A boy with a large bladder stone

Despite the frequent association of urinary tract infection with vesicoureteral reflux and urinary calculi, since vesicouretal reflux is induced by bladder stones, the coexistence of vesicoureteral reflux and bladder stones is rare. Because of its occurrence in children belonging to poor socioeconomic groups, it is believed to be a deficiency disorder. Most cases of bladder stones occur between the ages of 2 and 5 years. Common clinical presentations of bladder stones include urinary dribbling and enuresis, frequency of micturition, pain during micturition, pelvic pain and hematuria. We report the occurrence of a large bladder stone in a boy, who experienced intermittent Lower abdominal pain and urinary incontinence, both during the day and at night. He had been diagnosed with enuresis and treated in pediatric clinics for 1 year. Delayed diagnosis resulted in bladder stone formation. The stone was larger than 2.5cm and open vesicolithotomy was therefore selected as the best and safest treatment choice. His symptoms disappeared after surgery. Thorough metabolic and environmental evaluations of such cases are required on an individual basis. Bladder stones should be considered as a possible diagnosis in children presenting with urinary incontinence.

Metabolic risk factors in children with kidney stone disease

The evaluation of metabolic risk factor in children with renal stone disease is the basis of medical treatment aimed at preventing recurrent stone events and the growth of preexisting calculi. In this retrospective study, we evaluated the metabolic risk factors and clinical and family histories of 90 children with kidney stone disease who had been referred to our institution and subjected to clinical tests using a standardized protocol. The mean age of our pediatric patients was 10.7 years, and the male:female ratio was 1.14:1.0. Biochemical abnormalities were found in 84.4% of all cases. A single urine metabolic risk factor was present in 52.2% (n = 47) of the patients, and multiple risk factors were present in the remaining 31.1% (n = 28). Idiopathic hypercalciuria (alone or in combination) and hypocitraturia (alone or in combination) were the most frequent risk factors identified in 40 and 37.8% of these patients, respectively. Renal colic or unspecified abdominal pain were the most frequent forms of presentation (76.9%), with 97.5% of stones located in the upper urinary tract. In most patients, stone disease was confirmed by renal ultrasonography (77%). A positive family history in first-degree and second-degree relatives was found in 46.2 and 32.5% of the cases, respectively. We conclude that specific urine metabolic risk factors are found in most children with kidney stones and that hypocitraturia is as frequent as hypercalciuria. Very often there is a positive family history of renal stone disease in first- and second-degree relatives.

Pediatric nephrolithiasis: does treatment affect renal growth?

OBJECTIVES

The long-term effects of shock wave lithotripsy on the growth of pediatric kidneys are not well defined. Likewise, no long-term data regarding renal growth after ureteroscopy or percutaneous nephrolithotomy have been published. We studied the effect of urolithiasis on renal growth in our pediatric patient population.

METHODS

A total of 165 children were treated for urolithiasis at St. Louis Children's Hospital from March 1993 to December 2003. Of these 165 children, 74 were available for long-term follow-up. Four groups were evaluated: those who underwent shock wave lithotripsy, ureteroscopy, or percutaneous nephrolithotomy, and those who received no intervention. The expected renal length was calculated using Chen's nomogram, and the observed renal length was measured using renal ultrasonography. All measurements were performed by one pediatric radiologist. The expected and observed renal growth was determined by subtracting the renal length at baseline from the length at follow-up, divided by the number of months of follow-up. Statistical analysis used paired data for each treatment group, and comparisons were made on a nonparametric single-rank method.

RESULTS

Of the 74 children, 39 were boys and 35 were girls, with a mean age at treatment of 9 years (range 9 months to 14 years) and a mean follow-up of 6.2 years (range 1.3 to 13.1). In all groups, the comparison between the treated side and nontreated side for expected and actual kidney size and growth was calculated as described. None of the groups had statistically significant differences in the observed or predicted renal growth rates.

CONCLUSIONS

Shock wave lithotripsy, ureteroscopic stone extraction, and percutaneous nephrolithotomy do not appear to impair renal growth.

Genotype and haplotype determination of IL1B (g. −511C>T and g. +3954C>T) and (IL1RN) in pediatric nephrolithiasis

BACKGROUND

Nephrolithiasis is a multifactorial and polygenic disorder characterized by presence of stones in urinary tract. Interleukin1 (IL1) plays role in process of bone loss/hypercalciuria and is involved in formation of kidney stones. We investigated the association between IL1B promoter region and exon-5 (g.-511C>T and g. +3954C>T) polymorphism and variable number of tandem repeats in IL1 receptor antagonist, IL1RN (IVS2) with risk of stone formation in childhood nephrolithiasis in north Indian population.

METHODS

Control group of 60 healthy pediatric individuals (age range =4-16 y) and 50 pediatric nephrolithiasis patients (age range =2-14 y) were studied. Polymorphism was detected by PCR based restriction analysis. Haplotypes for IL1B and IL1RN were constructed using Arlequin v2.0 software.

RESULTS

Distribution of IL1RN gene polymorphism demonstrated significant difference (p=0.023). Pediatric patients had significantly higher frequency of allele I in IL1RN (16% vs. 1.7%). The distribution of IL1B (g. -511C>T and g. +3954C>T) genotypes in patients and controls were similar (p=0.263 and 0.694 respectively). There was a significant difference in haplotype frequencies between pediatric patients and control group (p<0.05). Haplotype T-E1-I showed>7-folds risk for nephrolithiasis (p=0.033; OR=7.07, 95% CI=1.16-42.84).

CONCLUSIONS

Significant association was observed for allele I(*) of IL1RN however, no association was observed for IL1B. Haplotype T-E1-I was significantly associated with higher risk of pediatric nephrolithiasis. These findings suggest that the IL1RN and haplotyping may be an influential marker for susceptibility to pediatric nephrolithiasis.

Evaluation of histologic changes in the urinary tract of hypercalciuric rats

Idiopathic hypercalciuria (IH) has been speculated to have a predisposing role in the development of urinary tract infection (UTI), due to the uroepithelial cell damage it leads to. In this study, we aimed to investigate the effects of hypercalciuria on the bladder, ureters, and kidneys in rats with experimentally induced hypercalciuria.Normocalcemic hypercalciuria was induced by furosemide (60 mg/100 mL of drinking water) administration to 16-week-old male Wistar Albino rats for 14 days. Calciuria (calcium/creatinine ratio, mg/mg, Ca/Cr) increased from 0.07+/-0.01 at the beginning of administration to 0.41+/-0.1 on day 14 (p=0.000). The Ca/Cr ratio was 0.14+/-0.06 at the beginning of the study and 0.25+/-0.06 on day 14 in the control group rats (p=0.002 vs. the hypercalciuric group rats on day 14). Bladder, ureter, and kidney specimens of the rats, dissected on the 14th day, were fixed in 10% formalin and 2.5% gluteraldehyde solutions for light and electron microscopic examination, respectively. Histopathological and ultrastructural examination of the hypercalciuric rats revealed proliferation and apical cytoplasmic vacuole formation in transitional epithelial cells, mitotic activity in the intermediate cell line, vasodilatation, edema, and separation of collagen fibers in the bladder and ureter specimens. Light microscopic examination of the kidney specimens revealed a lot of erythrocyte in the glomerular capillary lumen, while electron microscopy revealed vacuolization of proximal and distal tubules, tubular degeneration, interstitial edema, and vasodilatation.In this study, hypercalciuria was observed to have adverse effects on the cell architecture of the uroepithelium and disruption of the epithelial barrier of the bladder and ureters and all kidney structures, especially on the proximal epithelial cells.

[Study of renal morphology and function in children with nocturnal enuresis. Relationship with sensitivity or resistance to desmopressin]

BACKGROUND

In the last few years, there have been reports that children with nocturnal enuresis frequently have hypercalciuria. Likewise, children with desmopressin-resistant enuresis have recently been reported to have a higher renal concentration capacity than patients with desmopressin-sensitive enuresis.

OBJECTIVES

To study renal function and urinary calcium excretion and to register familial history of enuresis and urolithiasis in a group of children with enuresis, whether responders or nonresponders to desmopressin, followed-up in our hospital.

MATERIAL AND METHODS

A cohort of 60 patients (42 boys and 18 girls) who were referred to the hospital because of nocturnal enuresis.

RESULTS

Hypercalciuria was detected in 26 children (43.3 %) and hypocitraturia in eight (13.3 %). The frequency of hypercalciuria was higher in desmopressin-resistant patients than in desmopressin-sensitive patients, but this difference was not statistically significant. Sonographic renal morphological anomalies were detected in 11 children (18.3 %). No differences in renal handling of water were detected when the patients were distributed according to the grade of sensitivity to desmopressin.

CONCLUSIONS

In our cohort we found a high frequency of hypercalciuria in children with nocturnal enuresis. No differences were observed in maximal urinary osmolality among desmopressin-resistant and desmopressin-sensitive children.

[Imaging techniques and their impact in treatment management of patients with acute flank pain]

The purpose of this overview is to provide a general summary of the imaging techniques applied at the Vienna Hospital for the investigation of acute flank pain and the diagnosis of stone disease and the evaluation of their efficacy and impact on therapy management. The number of publications on the issue of "intravenous urography (IVU) vs computed tomography (CT)" is abundant; in recent years, advocates of CT make up the majority. In the Department of Urology at the Vienna Hospital, conventional techniques such as ultrasound and IVU besides UHCT still play an important role. This overview presents the advantages and disadvantages of the various imaging techniques for diagnosis of stone disease and evaluates their significance regarding therapy management of patients with acute flank pain.

Nephrolithiasis in children

A metabolic etiology is the most common cause for pediatric kidney stones. Appropriate evaluation of affected children should include assessment of stone type, if available, and assessment of predisposing factors in all cases. This review discusses the metabolic disorders that lead to nephrolithiasis with respect to the development of calcium, uric acid, struvite, and cystine stones. Environmental and hereditary factors are summarized to provide a guide in the evaluation of pediatric stone formers.

High incidence of kidney stones in Icelandic children

All children less than 18 years of age who were diagnosed with a first episode of kidney stones at pediatric referral centers in Iceland during the years 1995-2000 were studied retrospectively. The diagnosis was based on clinical features and results of imaging studies. Patients were invited for evaluation at the end of the study period. Twenty-six patients (15 females, 11 males), median age 9.4 (range 0.2-14.9) years, experienced 34 episodes of kidney stones. The annual incidence was 5.6 and 6.3 per 100,000 children less than 18 and 16 years of age, respectively. Abdominal pain was the most common symptom (N=17; 69%) and urinalysis revealed hematuria in 21 patients (80.8%), sterile pyuria in 17 (65%), and 2,8-dihydroxyadeninuria in two. Six patients (23%) had positive urine cultures at the time of diagnosis and five (20%) had urinary tract anomalies. Family history of kidney stones was positive in one third of patients. Metabolic risk factors for stone formation were identified in 22 of 23 patients (96%) who underwent evaluation. Hypercalciuria, the most common metabolic risk factor, was identified in 18 patients (78%). Stones passed spontaneously in nine patients (35%) and six patients had recurrent stone episodes. The incidence of kidney stones in Icelandic children is high compared with other Western populations, affecting females more than males. Underlying metabolic risk factors were identified in most patients.

Role of urinary supersaturation in the evaluation of children with urolithiasis

Timed urine collections are a standard part of the evaluation for predisposition to stone formation in children with urolithiasis. Supersaturation is defined as the ratio of the concentration of dissolved salt to its solubility in urine. The purpose of the present study was to determine if adding supersaturation to the standard timed urine collection increased the ability to detect a metabolic predisposition to stone formation. Thirty-two children with urolithiasis had 24-hour urine measurements of calcium, oxalate, citrate, uric acid, and cystine (the "traditional" evaluation), as well as supersaturation for calcium oxalate, calcium phosphate, and uric acid, on the same urine sample. Nine (28%) of the 32 were hypercalciuric, 2 (6%) hyperoxaluric, and 4 (12%) hypocitraturic. In total, 14 (44%) had a metabolic predisposition that was detected by the traditional evaluation. Supersaturation was elevated in 18 (56%), including nine who did not have metabolic predisposition detected by traditional evaluation. Urine volume was low in 17 (53%) of 32 children, including eight of nine children with abnormal supersaturation but normal traditional evaluation. Only one child with normal traditional evaluation and normal urine volume had elevated supersaturation. These results show that the benefit of adding supersaturation to the traditional evaluation was largely negated by consideration of urine volume.

Medical management of pediatric stone disease

Childhood urolithiasis remains endemic in certain parts of the world, namely, Turkey and the Far East. The prevalence of nephrolithiasis in North American children varies widely among geographic regions and accounts for 1 per 1000 to 1 per 7600 pediatric hospital admissions. Stones occur in children of all ages. The clinical manifestations of stone disease are often more subtle in children when compared with the dramatic adult presentation. This article discusses the evaluation and medical management of pediatric stone disease.

Diagnostic yield of parathyroid hormone testing in children evaluated for hypercalciuria

Hypercalciuria is a frequent cause of non-glomerular hematuria in pediatric patients. Because hypercalciuria can be secondary to primary hyperparathyroidism, measurement of serum parathyroid hormone (PTH) levels is often performed in children with this urinary abnormality. A retrospective chart review was performed to determine the diagnostic yield of PTH measurements when performed under these clinical circumstances. Over a 30-month period (January 1, 2001 to September 30, 2003), among 31 children who had a PTH determination, the level was elevated in 1 (3%) patient. Based on these findings and the serious nature of untreated primary hyperparathyroidism, serum PTH level should be measured in pediatric patients with newly diagnosed hypercalciuria.

Evaluation of hematuria in children

The detection of blood in a child's urine is alarming and often prompts many laboratory studies. Hematuria is one of the most important signs of renal or bladder disease, but proteinuria often is a more important diagnostic and prognostic finding. The physician should ensure that serious conditions are not overlooked, avoid unnecessary laboratory studies, reassure the family, and provide guidelines for additional studies if there is a change in the child's course. This article provides an approach to the evaluation and management of hematuria in a child. Many tests have been recommended for the child with hematuria, but no consensus exists on a systematic evaluation.