Pediatric Stone Formers Research Articles

833 IS BMI ASSOCIATED WITH STONE FORMATION IN CHILDREN? SINGLE CENTER, PROSPECTIVE ANALYSIS

INTRODUCTION AND OBJECTIVES: Multiple reports exist identifying an increasing epidemic of pediatric urolithiasis in the modern era. Causative factors have been postulated, such as the obesity and fast food epidemics. We hypothesize that BMI is not truly causative, but more likely a confounding factor, in pediatric stone formers. METHODS: A two-year prospective clinical trial enrolled 52 patients through the Pediatric Urology department at the Childreni s Hospital of Pittsburgh. Patient demographics, BMI, method of stone diagnosis, stone analysis, 24 hour urine studies, labs and spot urine studies, and treatments were catalogued. Logistic regression analysis was used to compare variables among stone forming children iU age 18. RESULTS: Data on BMI was available for 49 of 52 stone forming children. Imaging data was available in 46 of 49 patients, including confirmation by CT in 40 (87%), ultrasound in 3 (6.5%), and KUB in 3 (6.5%). The median age of presenting children was 15 (mean: 14.4 2.5), median stone burden 2.8mm (mean: 3.5 1.7) and median BMI 20.0 (mean: 20.4 4.2). Approximately 10% (5/49) children were overweight (BMI 25-30) and only 2% (1/49) were obese. Infected stones were present in 2 children (4.3%), and end stage renal failure in 1 (2.2%). Litholink® studies were completed on all 49 patients; 24hr urine electrolytes are as outlined in Table 1. No patients had cystinuria. CONCLUSIONS: mong pediatric stone formers, we did not find higher rates of obesity than compared with the local population. In fact, all overweight children forming stones in our cohort accounted for only 10% of total patients. Both normal and overweight children had low citrate levels by Litholink assay, although overweight children had a more substantial reduction in urinary citrate. Greater patient numbers are needed to determine the true effect of obesity on 24 hour urine parameters, and the reversible causes for increased stone formation, including dietary analysis.

2248 BODY WEIGHT CORRELATES WITH TOTAL URINARY CALCIUM AND OXALATE IN PEDIATRIC AND ADULT STONE FORMERS

You have accessJournal of UrologyStone Disease: Evaluation & Medical Management II1 Apr 20122248 BODY WEIGHT CORRELATES WITH TOTAL URINARY CALCIUM AND OXALATE IN PEDIATRIC AND ADULT STONE FORMERS Mark D. Sawyer, John C. Thomas, Tracy E. Hunley, Ryan B. Pickens, Mary S. Dietrich, S. Duke Herrell, and Nicole L. Miller Mark D. SawyerMark D. Sawyer Nashville, TN More articles by this author , John C. ThomasJohn C. Thomas Nashville, TN More articles by this author , Tracy E. HunleyTracy E. Hunley Nashville, TN More articles by this author , Ryan B. PickensRyan B. Pickens Nashville, TN More articles by this author , Mary S. DietrichMary S. Dietrich Nashville, TN More articles by this author , S. Duke HerrellS. Duke Herrell Nashville, TN More articles by this author , and Nicole L. MillerNicole L. Miller Nashville, TN More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.2425AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Obesity appears to increase stone risk in adults. However, since adipose tissue is not very metabolically active and patients with identical body mass index (BMI) can have very different body weights, absolute body weight may be a more important predictor of stone risk. The intent of this study is to further evaluate the relationship between body weight and calcium and oxalate in both adult and pediatric stone formers. METHODS All pediatric and adult stone patients at our institution with a 24 hour urine study analyzed by Litholink were identified. Selected for inclusion were initial baseline urine studies with an adequate collection without cystinuria. 338 patients (children <17 (n=135) and adults (n=203)) met inclusion criteria (M=162, F=176; ages 2-78; weight 11.6-147kg). Patients were grouped in 10 kg intervals (except for patients >100 kg who were grouped together) and compared (figure and table 1). Univariate linear regression was then used to compare the effect of weight in pediatric and adult subsets to the entire cohort (table 2). Table 1. Urine Constitutuents and Body Weight (Adult and Pediatric Combined) Group 1 2 3 4 5 6 7 8 9 10 Weight (kg) 10−19.9 kg 20−29.9 kg 30−39.9 kg 40−49.9 kg 50−59.9 kg 60−69.9 kg 70−79.9 kg 80−89.9 kg 90−99.9 kg >100 kg N 9 18 36 37 48 42 53 34 37 24 Calcium (mmol/24h) 2.15±0.89 2.37±1.08 3.00±1.55 3.16±1.93 3.94±1.65 5.53±2.87 5.40±2.74 6.14±2.44 6.12±2 .61 9.05±4.49 Oxalate (mmol/24h) 0.203±0.057 0.319±0.213 0.349±0.104 0.319±0.13 0.34±0.15 0.43±0.27 0.43±0.20 0.407±0.14 0.450±0.15 0.53±0.22 Table 2. Univariate Linear Regression Coefficients of Regression for Body Weight (β) with Standard Error (SE) and Coefficients of Determination (R2) for Children, Adults and Combined Pediatric Adult Combined β±SE R2 β±SE R2 β±SE R2 Calcium 0.066±0.009 0.303 0.065±0.010 0.167 0.071±0.0084 0.333 Oxalate 0.00253±0.00072 0.078 0.00206±0.00071 0.036 0.00208±0.00068 0.055 RESULTS Both calcium and oxalate excretion increase with weight in adults and children. The correlation with total calcium in the combined group is very high (r=0.58). With linear regression, the coefficients of regression for body weight as a predictor of total calcium and oxalate are nearly identical in children and adults. CONCLUSIONS Body weight is an important predictor of calcium and oxalate excretion in both children and adults. Overall, it explains 33.3% and 5% of total variation in the daily urinary calcium and oxalate, respectively. These findings could help explain the observed increase in stone prevalence with increasing obesity and suggests that there should be increased emphasis on overweight patients losing weight to prevent recurrence, regardless of age. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e906-e907 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Mark D. Sawyer Nashville, TN More articles by this author John C. Thomas Nashville, TN More articles by this author Tracy E. Hunley Nashville, TN More articles by this author Ryan B. Pickens Nashville, TN More articles by this author Mary S. Dietrich Nashville, TN More articles by this author S. Duke Herrell Nashville, TN More articles by this author Nicole L. Miller Nashville, TN More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Infrared spectroscopic analysis of urinary stones (including stones induced by melamine-contaminated milk powder) in 189 Chinese children

AimThe aim of the study was to investigate the composition of the stones in Chinese children with urolithiasis, including peculiar stones induced by melamine-contaminated milk powder. Materials and MethodsBetween 1999 and 2009, 189 urinary stones from children of East China were received at our institution. Among them, 12 stones were received from pediatric stone formers with a history of consuming melamine-contaminated milk powder in 2008; and the remaining stones were defined as “natural” stones. All stones were analyzed by Fourier transform infrared spectroscopy. ResultsAmong 177 “natural” stones, whewellite stone (49.72%) was observed most frequently followed by weddellite stone (15.25%), uric acid anhydrous stone (9.6%), carbapatite stone (9.04%), cystine stone (9.04%), ammonium acid urate stone (4.52%), struvite stone (2.26%), and sodium urate stone (0.56%). Twelve young children who consumed melamine-contaminated milk powder were younger than 3 years, and their stones were composed of a mixture of uric acid dihydrate and ammonium acid urate based on Fourier transform infrared spectroscopy. In addition, the stones were radiolucent and could be dissolved by urine alkalinization. ConclusionsOur study emphasizes the relatively high rate of calcium oxalate stones and cystine stones, and the relatively low rate of struvite stones in Chinese children with urolithiasis. The stones caused by melamine-contaminated milk powder are composed of the mixture of uric acid dihydrate and ammonium acid urate.

1382 ARE CHILDREN WITH STONES AT RISK FOR BREAKING BONES? BONE MINERAL DENSITY ANALYSIS IN PEDIATRIC STONE FORMERS

You have accessJournal of UrologyPediatrics: Stone Disease & Tumors1 Apr 20111382 ARE CHILDREN WITH STONES AT RISK FOR BREAKING BONES? BONE MINERAL DENSITY ANALYSIS IN PEDIATRIC STONE FORMERS Candace Granberg, Katherine Twombley, Aditya Bagrodia, Khashayar Sakhaee, Naim Maalouf, Linda A. Baker, and Nicol C. Bush Candace GranbergCandace Granberg Dallas, TX More articles by this author , Katherine TwombleyKatherine Twombley Dallas, TX More articles by this author , Aditya BagrodiaAditya Bagrodia Dallas, TX More articles by this author , Khashayar SakhaeeKhashayar Sakhaee Dallas, TX More articles by this author , Naim MaaloufNaim Maalouf Dallas, TX More articles by this author , Linda A. BakerLinda A. Baker Dallas, TX More articles by this author , and Nicol C. BushNicol C. Bush Dallas, TX More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1227AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Adult stone formers are known to have lower bone mineral density (BMD) and higher rates of osteoporotic fractures compared to non-stone formers. Low BMD in children is associated with increased risk of bone fractures. The objective of this study was to evaluate BMD among our pediatric stone patients. METHODS Retrospective review of all patients undergoing dual-energy x-ray absorptiometry (DXA) scan since 2000 with a confirmed diagnosis of urolithiasis was performed. Immobilized patients were excluded. Z-scores, expressed as number of age- and gender-matched standard deviations from the mean, and 24-hour urine profiles were assessed. Since 2009, patients with ≥ 1 stone have been prospectively queried about fracture history. Hypercalciuria was defined as Ca/Cr ratio > 0.2 and/or > 4 mg/kg/day. Statistical testing was performed with Fisher's exact and t-test, with p<0.05 considered statistically significant. RESULTS 132 confirmed stone-formers (76F:56M) underwent DXA analysis at average age 12.2 years. Average lumbar and radial forearm BMD Z-scores were −0.8 (range −4.2 to +2.7) and −0.5 (range −2.9 to +2.2), respectively. Lumbar BMD Z-scores were < −1.0 in 51/127 (40.2%) patients, and < −2.0 in 21/127 (16.5%). 79 of 132 children have completed 24-hour urine stone risk analysis, demonstrating 45.6% with hypercalciuria. Table 1 stratifies BMD Z-score based on presence or absence of hypercalciuria. Hypercalciuria was not associated with risk of BMD Z-score < −1 (p=0.36). Among 22 stone-formers who were prospectively queried about bone fracture history, 7 (31.8%) had one or more fractures. Average BMD Z-score in those with versus without fractures was −1.1 and −0.7, respectively. Table 1. DXA results based on presence or absence of hypercalciuria. Non-hypercalciuric Hypercalciuric p-value Total patients (n=79) 43(54.4%) 36(45.6%) Mean lumbar Z-score(SD) −0.9(1.08) −1.0(1.83) 0.76 Z-score < -1, n(%) 22(51.2) 14(38.9) 0.36 Z-score < -2, n(%) 9(20.9) 7(19.4) 1.00 Mean radial Z-score(SD) −0.2(1.35) −0.8(1.46) 0 CONCLUSIONS Pediatric stone disease may identify an at-risk population for future osteoporosis and fractures. Over 40% of our pediatric stone formers had Z-scores < −1.0, a value associated with increased fracture risk in children. Screening DXA scans should be performed in pediatric stone-formers and/or hypercalciurics, particularly in those with a history of fracture. Since adolescence is the period for peak bone mass accrual, it may be the ideal time for dietary and/or medical intervention to decrease future osteoporotic risk. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e551 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Candace Granberg Dallas, TX More articles by this author Katherine Twombley Dallas, TX More articles by this author Aditya Bagrodia Dallas, TX More articles by this author Khashayar Sakhaee Dallas, TX More articles by this author Naim Maalouf Dallas, TX More articles by this author Linda A. Baker Dallas, TX More articles by this author Nicol C. Bush Dallas, TX More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Epidemiologic insights into pediatric kidney stone disease

The epidemiology of pediatric kidney stone has not yet been as rigorously defined as that of adult kidney stone disease. Herein, we review our recent epidemiologic works characterizing pediatric stone disease using the Kids' Inpatient Database (KID). Specifically we investigated the age and gender distribution of pediatric kidney stone disease, changes in disease prevalence over time, and medical comorbidities associated with this disorder. We identified patients by International Classification of Disease 9th Edition (ICD-9) codes for renal and ureteral calculi as the primary diagnosis. Medical comorbidities were identified using specific comorbidity software. Statistical comparisons between children with and without stone disease were performed. In the first decade of life, stone disease was more prevalent among males than females; however, in the second decade of life females were more commonly affected. Of note, there was a significant increase in treated stone disease across both genders between 1997 and 2003. We also found that the risk of kidney stone diagnosis in children younger than 6 years of age was significantly associated with hypertension and diabetes mellitus. The gender distribution among pediatric stone formers varies significantly by age, although overall females have a greater prevalence than males. There is also a strong association of stone disease and both diabetes and hypertension, although this was only observed in children less than 6 years of age. Taken all together, these findings suggest that urolithiasis in the young child is a complex systemic disease process.

New horizons in the management of patients with cystinuria

Although the formation of cystine stones is seen in only a small fraction of all patients with urolithiasis, this disease is associated with a pronounced morbidity. The difficult clinical management of these patients, with the aim of arresting or decreasing the rate of recurrent stone formation, is well recognized. This review summarizes some recent knowledge. An early and correct diagnosis of cystinuria is fundamental for a successful course of the disease in these patients. Formation starts early in life, and attention to this diagnosis is necessary for the paediatric stone formers. New radiological and biochemical improvements seem useful in this respect. A combination of medical tools is usually necessary to influence the very often, troublesome stone-forming activity. Urine dilution, alkalization and chelating therapy have remained the cornerstones of the therapeutic approach. The importance of a high urine pH has been further emphasized, and the possibility to use acetazolamide is a promising improvement of the medical treatment. In order to increase the compliance and reduce the need of active stone removal, special stone clinics seem to be of particular value. The understanding of the genetic background might open future treatment alternatives. Patients afflicted by cystine stone disease need an aggressive medical treatment, gentle stone-removing surgery and careful follow-up.

Intestinal Colonization with Oxalobacter formigenes and its Relation to Urinary Oxalate Excretion in Pediatric Patients with Idiopathic Calcium Urolithiasis

Oxalobacter formigenes is an intestinal bacterium that utilizes oxalate as the only source of energy. It has been suggested that the lack of colonization with this organism may be a risk factor for calcium oxalate urolithiasis. Because this problem was not investigated in pediatric stone formers, we decided to assess it in our patients. The presence of O. formigenes in stool samples of 76 children and adolescents (aged 4.1-18 years) with idiopathic calcium urolithiasis (36 with chemically confirmed calcium oxalate stones and 40 children with a strong clinical suspicion of this type of urolithiasis) was assessed using PCR method. Simultaneously, urinary oxalate excretion was measured in this group. Fifty healthy, age- and sex-matched subjects served as controls. O. formigenes was found in 21/76 patients (27.6%). In controls, frequency of colonization was similar (26%). The median 24h urinary oxalate excretion in patients colonized with O. formigenes was significantly lower in comparison with non-colonized patients, 0.319 (range 0.141-0.546) and 0.437 (range 0.198-0.967) mmol/1.73 m(2)/24h, respectively. Higher urinary oxalate excretion in children with calcium urolithiasis may be a result of the absence of O. formigenes. The reasons for similarly low intestinal colonization with this bacterium in normal subjects and stone formers remain speculative. Thus, further studies are necessary to clarify this issue.

Composition of Renal and Bladder Calculi in Pediatric Stone Formers

Purpose To analyze the chemical composition of the core and surface of renal and bladder calculi and its importance in determining etiology of stone formation. Material and Methods The mainstay of stone analysis was infrared spectroscopy. In stones with compound mixtures chemical examination was undertaken. Stones with Amonium Hydrogen Urate (AHU) in the core were evaluated by scanning electron microscopy (SEM)to determine crystal structures and stones Results Of the 2039 stones analyzed, 726 (36%) were composed purely of a single compound salt and 64% were mixed stones. Overall frequency of compounds in stones was AHU in 58%, calcium oxalate monohydrate (COM) in 63%, calcium oxalate dehydrate (COD) 20%, uric acid (UA) 6%, calcium phosphate apatite (CAP) 12% and struvite in 8%. Surface and core analysis was possible in 1274 renal stones. Frequency of compounds in core of renal stones were AHU 64%, CaOx 41%, UA 3%, CAP 9% and struvite 5%. In the surface analysis, AHU reduced to 30% and CaOx increased to 72%. Stratification of pure stones by age groups, A ( 10 years), showed differences in pattern of stones types. Separate core and surface analysis was possible in 198 bladder stones. Frequency of compounds in core of bladder stones was AHU 61%, CaOx 35%, UA 10%, CAP 7%, and struvite 6%. Surface analysis again showed low AHU (37%), high CaOx (52%) and increased UA (16%), CAP (12%) and struvite (15%). Conclusions The presence of AHU in kidney and bladder calculi suggests a common cause in our population i.e. endemic calculi due to poor nutrition, diarrhea and dehydration. Increasing age gives pattern similar to developed world where calcium oxalate predominates.

Plasma oxalate level in pediatric calcium stone formers with or without secondary hyperoxaluria

Plasma oxalate (POx) concentration is significantly elevated in primary hyperoxaluria, severe renal failure or ethylene glycol poisoning. In these conditions, the degree of hyperoxalemia correlates with the severity of systemic calcium oxalate (CaOx) deposition and should be therefore carefully monitored. Although secondary hyperoxaluria (secHyOx) is a common finding in pediatric patients with kidney stone disease, very little is known about POx in this condition. We therefore evaluated POx level in 59 children and adolescence with calcium urolithiasis (34 confirmed by CaOx stone analysis and 25 children with a strong clinical suspicion of this type of urolithiasis), with or without "mild" secHyOx. A control group consisted of 41 healthy sex- and age-matched children. We found that POx was significantly increased in children with calcium urolithiasis and secHyOx compared to healthy children (9.16 +/- 3.60 vs. 6.42 +/- 2.53 micromol/l), but that was not the case in children with calcium urolithiasis but with normal urinary oxalate excretion (7.12 +/- 3.33 micromol/l). We conclude that POx may be slightly increased in some pediatric calcium stone formers with secHyOx, probably related to intestinal oxalate hyperabsorption.

Comparison of Pediatric Stone-Formers with and without mutations in Soluable Adenylate Cyclase

PURPOSE Two-thirds of children with urolithiasis have hypercalciuria. Recently, a candidate gene for absorptive hypercalciuria (AH) was mapped to chromosome 1q23.3-24 in the adult population. In adults, the presence of up to 6 identified base substitutions in the soluble adenylate cyclase gene (sAC) was associated with a 2.2- to 3.5-fold increased risk for AH. We screened a pediatric population of stone formers for sAC sequence variations. MATERIAL AND METHODS Pediatric patients with stone disease were offered study participation if they met the following criteria: family history of stones; hypercalciuria (urine calcium/creatinine ratio > 0.21 mg/mg creatinine or 24 hour calcium excretion > 4 mg/kg/day); and/or calcium stones on stone analysis. Serum laboratories, spot and 24-hour urine, and bone mineral density (BMD) were collected. Patients were excluded for metabolic conditions predisposing to stone disease. Probands were genotyped for 6 previously identified base substitutions in the sAC gene. Comparisons were made between probands with and without sAC substitutions using Fisher's exact test. RESULTS Of 46 children recruited, sAC substitutions were identified in 19 (41%). Clinical parameters were similar in patients with and without substitutions: positive family history in 14/17 (82%) vs. 21/27 (78%); hypercalciuria in 13/19 (68%) vs. 22/27 (82%); and mean number of stone events 2.1 vs. 2.8. Overall, 5/16 (31%) had abnormal BMD (age-adjusted Z-scores < -1.5). More patients with base substitution(s) had abnormal BMD scores (4/9, 44%, vs. 1/7, 14%, p = 0.31), tending towards lower Z-scores (-1.26 vs. -0.3). CONCLUSIONS Of 46 pediatric stone formers, 31% had abnormal BMD scores, and 41% of probands had sAC gene base changes previously identified in adults to increase risk for stones and osteoporosis. This warrants further investigation for potential genetic screening and therapeutic interventions to prevent pediatric stone formation and long-term osteoporotic risk.

COMPARISON OF PEDIATRIC STONE-FORMERS WITH AND WITHOUT MUTATIONS IN SOLUBLE ADENYLATE CYCLASE

Abstract Purpose Two-thirds of children with urolithiasis have hypercalciuria. Recently, a candidate gene for absorptive hypercalciuria (AH) was mapped to chromosome 1q23.3-24 in the adult population. In adults, the presence of up to 6 identified base substitutions in the soluble adenylate cyclase gene (sAC) was associated with a 2.2- to 3.5-fold increased risk for AH. We screened a pediatric population of stone formers for sAC sequence variations. Material and Methods Pediatric patients with stone disease were offered study participation if they met the following criteria: family history of stones; hypercalciuria (urine calcium/creatinine ratio > 0.21 mg/mg creatinine or 24 hour calcium excretion > 4 mg/kg/day); and/or calcium stones on stone analysis. Serum laboratories, spot and 24-hour urine, and bone mineral density (BMD) were collected. Patients were excluded for metabolic conditions predisposing to stone disease. Probands were genotyped for 6 previously identified base substitutions in the sAC gene. Comparisons were made between probands with and without sAC substitutions using Fisher's exact test. Results Of 46 children recruited, sAC substitutions were identified in 19 (41%). Clinical parameters were similar in patients with and without substitutions: positive family history in 14/17 (82%) vs. 21/27 (78%); hypercalciuria in 13/19 (68%) vs. 22/27 (82%); and mean number of stone events 2.1 vs. 2.8. Overall, 5/16 (31%) had abnormal BMD (age-adjusted Z-scores Conclusions Of 46 pediatric stone formers, 31% had abnormal BMD scores, and 41% of probands had sAC gene base changes previously identified in adults to increase risk for stones and osteoporosis. This warrants further investigation for potential genetic screening and therapeutic interventions to prevent pediatric stone formation and long-term osteoporotic risk.

Circadian variation in urine pH and uric acid nephrolithiasis risk

The proportion of uric acid stones in paediatric stone formers is estimated at 3–4% in the United States [1], although reports from Armenia and Turkey indicate higher proportions of 7 and 15%, respectively [2,3]. Risk factors for uric acid stones include hyperuricosuria, low urinary volume and unduly acidic UpH (<5.5) [4]. Acidic UpH is a recognized risk factor in children consuming a ketogenic diet [5], or those with chronic diarrhoea. In adults, an acidic urine pH is the most common abnormality that predisposes to idiopathic uric acid nephrolithiasis [4]. Urinary alkalinization with potassium citrate is an effective treatment for uric acid kidney stones in adults [6]. We report the case of a 13-year-old boy who presented with recurrent uric acid stones that did not respond to a conventional regimen of potassium citrate therapy.

Evaluation of children with urolithiasis

Objectives:To describe an evaluation protocol for pediatric stone formers for risk assessment and management strategies.Materials and Methods:Between 2002-2006, 2618 children of age three months to 15 years were evaluated for stone disease. Evaluation included demographics, history, anthropometry, diet, ultrasound, X-ray KUB, IVU, blood and 24h urine chemistry and cultures. Stones were analyzed by IR spectroscopy.Results:The median age was seven years with a M:F ratio of 2.2:1. Of the 2618 patients, 2216 presented with normal renal function and 402 with renal failure. Main symptoms were abdominal pain (33%), flank pain (38%) and fever (38%). Renal failure patients also had shortness of breath (38%) and oligo-anuria (26%). Children were malnourished with height and weight deficits in 65% and 76% respectively. Diet was low in protein (74%), calcium (55%) and fluids in (55%), high in oxalate (55%), sodium (39%), purines (42%) and refined sugar (41%). Overall urine cultures were positive in 1208 (46%) with E. coli (38%) and Klebsiella (8%).Stone distribution was renal in 64%, ureter in 8%, bladder in 18%, bilateral in 40% and multiple sites in 18%. Median stone size was >1.5-2.0 cm. The frequency of compounds in stones was ammonium urate (58%), calcium oxalate (63%), uric acid (6%), calcium phosphate (12%) and struvite (8%). Metabolic abnormalities included hypovolumia (31%), hypocitraturia (87%), hyperoxaluria (43%) and hyperuricosuria (26%). Dietary and medical treatment corrected risk factors in two-thirds of patients with a recurrence rate of about 1.15%.Conclusion:An evaluation based on history, imaging, diet, metabolic analysis and stone type can help to tailor management strategies.

Pediatric urolithiasis: developing nation perspectives.

We evaluated epidemiology, etiology, dietary and urinary risk factors, and the composition of calculi in pediatric stone formers in Pakistan. This retrospective study includes 1,440 children treated between 1987 and 2000. Case records were reviewed for demographics, etiology and clinical symptoms. Dietary and urinary risk factors were analyzed prospectively in idiopathic stone formers. Stone composition was analyzed by infrared spectroscopy. There were 1,075 males and 365 females for a male-to-female ratio of 3:1. The peak age for renal and bladder stones was 6 to 10 and 1 to 5 years, respectively. Overall 795 stones (55%) were renal, 198 (14%) were ureteral and 447 (31%) were vesical. Bladder stones were present in 60% of cases in the mid 1980s but decreased to 15% in the mid 1990s. The clinical symptoms were abdominal pain in 511 patients (51%) and fever in 193 (19.5%). There were anatomical abnormalities in 96 patients (12%), metabolic abnormalities in 206 (25%), infection stones in 60 (7%) and idiopathic stones in 444 (55%). Urinary analysis in idiopathic stone formers revealed hypercalciuria in 17 (11%), hyperoxaluria in 62 (40%), hyperuricosuria in 41 (27%) and hypocitruria in 97 (63%). Diet involved a low intake of protein in 60 cases (44%), calcium in 45 (33%), potassium in 105 (77%) and high oxalate in 75 (55%). The composition was calcium oxalate in 362 stones (47%), ammonium hydrogen urate in 210 (27%) and struvite in 49 (6.4%). Stones recurred in 30 patients (2%). The pattern of calculous disease changed from a predominantly lower tract site in the mid 1980s to the upper tract in the mid 1990s. Stone composition, urinary risk factors and dietary analysis suggest that diet, dehydration and poor nutrition are the main causative factors of stone disease.

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.

Aetiological Factors in Paediatric Urolithiasis

The aetiology of stones in children differs from that in adults. Young children, especially boys, are prone to infective stones, although this type of calculi is decreasing in frequency over time in prosperous countries. Two monogenic causes, cystinuria and hyperoxaluria, each account for 5–15% of paediatric stones. Increased factors for stone formation in children include prematurity, neurological problems, ketogenic diet and reconstructed or augmented bladders. Hypercalciuria is commonly found in paediatric stone formers, is usually idiopathic and is only rarely associated with hypercalcaemia. All children with stones should undergo a metabolic evaluation.

Metabolic Risk Factors in Pediatric and Adult Calcium Oxalate Urinary Stone Formers: Is There Any Difference?

Objectives: Urolithiasis in children is recognized with an increasing frequency, while exact etiological factors remain to be determined. The aim of this study is to compare the metabolic risk factors and saturation of urine in pediatric and adult calcium oxalate (Ca-Ox) stone formers. Methods: A total of 33 pediatric (mean age: 6.8 ± 3.1 years) and 120 adult patients (mean age: 39.7 ± 5.7 years), with documented Ca-Ox urinary stone disease, underwent a comprehensive metabolic evaluation at our institution. Beside a broad serum analysis, concentrations of calcium, oxalate, magnesium, uric acid and citrate were measured in 24-hour collected urine. Saturation of urine was calculated by Marshall-Robertson’s nomograms. Results: Hypocitraturia, observed in 60.6%, and hypomagnesuria, detected in 39.4%, but not hypercalciuria, were the most common metabolic risk factors in the pediatric group. In adults, hypercalciuria still represented one of the major metabolic risk factors, detected in 44.1%, although hypocitraturia, observed in 45.8%, was the most prevalent metabolic risk factor, as it was in the pediatric group. Pediatric cases had significantly (p < 0.05) higher prevalence of hypocitraturia, hypomagnesuria and supersaturated urine when compared to adults. Metabolic abnormalities could be detected in a high percentage (82%) of primary and recurrent pediatric Ca-Ox stone formers, but not in primary adult stone formers. Conclusions: Metabolic risk factors significantly differ in pediatric and adult Ca-Ox stone formers. Hypocitraturia and hypomagnesuria seem to play a major role in stone formation, and metabolic abnormalities can be detected in a significant percentage of both primary and recurrent pediatric stone formers. Thus, a comprehensive metabolic evaluation is of utmost importance for all children with Ca-Ox stones.

Pediatric Urolithiasis: Developing Nation Perspectives

We evaluated epidemiology, etiology, dietary and urinary risk factors, and the composition of calculi in pediatric stone formers in Pakistan. This retrospective study includes 1,440 children treated between 1987 and 2000. Case records were reviewed for demographics, etiology and clinical symptoms. Dietary and urinary risk factors were analyzed prospectively in idiopathic stone formers. Stone composition was analyzed by infrared spectroscopy. There were 1,075 males and 365 females for a male-to-female ratio of 3:1. The peak age for renal and bladder stones was 6 to 10 and 1 to 5 years, respectively. Overall 795 stones (55%) were renal, 198 (14%) were ureteral and 447 (31%) were vesical. Bladder stones were present in 60% of cases in the mid 1980s but decreased to 15% in the mid 1990s. The clinical symptoms were abdominal pain in 511 patients (51%) and fever in 193 (19.5%). There were anatomical abnormalities in 96 patients (12%), metabolic abnormalities in 206 (25%), infection stones in 60 (7%) and idiopathic stones in 444 (55%). Urinary analysis in idiopathic stone formers revealed hypercalciuria in 17 (11%), hyperoxaluria in 62 (40%), hyperuricosuria in 41 (27%) and hypocitruria in 97 (63%). Diet involved a low intake of protein in 60 cases (44%), calcium in 45 (33%), potassium in 105 (77%) and high oxalate in 75 (55%). The composition was calcium oxalate in 362 stones (47%), ammonium hydrogen urate in 210 (27%) and struvite in 49 (6.4%). Stones recurred in 30 patients (2%). The pattern of calculous disease changed from a predominantly lower tract site in the mid 1980s to the upper tract in the mid 1990s. Stone composition, urinary risk factors and dietary analysis suggest that diet, dehydration and poor nutrition are the main causative factors of stone disease.

Infection stones in children: A twenty-seven-year review

Objective. The objective of this study was to determine the relationship between urinary tract infection and pediatric urolithiasis and to characterize the pediatric infection stone former. Methods. Two hundred seventy consecutive pediatric stone formers presenting over a twenty-seven-year period were studied. Of these, 161 children (60%) had infection-related stones. Account was taken of stone composition, anatomic location, associated anatomic lesions, and the rate of stone recurrence over a median follow-up of three years. Results. The mean age of children with infection stones was 4.9 years, with two-thirds being under six years of age. Proteus mirabilis accounted for 82 percent of pure urine cultures. Seventy percent of stones were renal and 30 percent were ureteral or intravesical. One-third of patients had anatomic lesions (pelviureteric obstruction, primary obstructed megaureter, and others) contributing to stone formation. Recurrent stones occurred in 14 percent of cases. Conclusions. This study reaffirms the prodominance of urinary tract infection secondary to P mirabilis as the leading cause of pediatric urolithiasis in the United Kingdom. The significant recurrence rate suggests the importance of prophylactic antibiotics, surgical correction of congenital anomalies, and long-term follow-up of this patient population.