Renal calculi in children

An increasing number of paediatric patients of all ages with renal calculi are being seen in outpatient clinics worldwide. This is attributed to changes in environmental factors like diet, fluid intake and obesity. In children however, genetic and/or metabolic disorders are still the main reason for kidney stones. Next to hypercalciuria, which is generally considered to be the most frequent risk factor, other lithogenic or stone-inhibitory disorders like hypocitraturia or hyperoxaluria and a variety of renal tubular diseases have to be evaluated by urine and/or blood analysis. Non-specific symptoms like growth retardation, intestinal malabsorption or bone demineralization are to be considered not only to avoid further complications, but for diagnostic purposes. In preterm infants a high incidence of nephrocalcinosis is observed. These infants often have a combination of immature kidney function or medication that leads to relative hypocitraturia. Concise evaluation to diagnose the underlying patho-mechanism as early as possible is mandatory in all paediatric patients. In more than three-quarters of children a metabolic basis of urolithiasis/nephrocalcinosis will be found. Early treatment by reducing urinary saturation index by increasing fluid intake, by providing crystallization inhibitors, but also by disease specific medication prevents recurrent kidney stones and/or progressive nephrocalcinosis and therefore deterioration of renal function.     

Nephrolitiasis in a patient with cystic fibrosis

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Defects in the CFTR gene cause abnormal chloride conductance across the apical membrane of epithelial cells, which results in progressive lung disease and also affects other organs. Because life expectancy has increased, other complications of CF have become more apparent. We present a patient with CF and symptomatic nephrolithiasis. Several stones were evident in both kidneys. A 24-hour urine sample showed hyperoxaluria (141 mg/24 h/ 1.73 m(2)) and hypocitraturia and (206 mg/24 h/1.73 m(2), 177 mg citrate/g creatinine). Nephrolithiasis should be included in the differential diagnosis of patients with CF and abdominal pain; urinary excretion of oxalate and citrate should be investigated.     

Medullary sponge kidney associated with distal renal tubular acidosis in a 5-year-old girl

Introduction Medullary sponge kidney (MSK) is characterized by cystic dilatation of the inner medullary collecting ducts, which causes the kidneys to resemble a sponge.Case report Although distal renal tubular acidosis (dRTA) is commonly observed in patients with MSK, we report a 5-year-old girl with MSK who had features of both dRTA (nephrocalcinosis, hypercalciuria, hypocitraturia) and proximal tubular dysfunction (hyperuricosuria, impaired tubular phosphate reabsorption and proteinuria).Discussion Metabolic acidosis, hypercalciuria, hypocitraturia, tubular phosphate reabsorption and growth retardation in the patient improved with alkali therapy.     

Studies on the urinary calcium excretion in children with hematuria of postglomerular origin: effects of the variation of dietary calcium and sodium intake

The effect of different dietary regimens and of an oral calcium (Ca) load was studied in 30 children with postglomerular hematuria, 8 of whom were renal stone formers. In addition we investigated the urinary inorganic phosphate complex composition in 12 of them, based on the principles of complex equilibria. Twenty-one of the 30 hematuric children with a urinary Ca/creatinine (Ca/cr) ratio of greater than or equal to 0.6 (mmol/mmol) were regarded as hypercalciuric. Low calcium intake normalised the ratio in 11 patients, fulfilling the definition of absorptive hypercalciuria, but not in the other 10 patients with renal hypercalciuria. Sodium restriction combined with low calcium diet induced a further significant decrease of the urinary Ca/cr ratio to a normal range in both forms of hypercalciuria (mean +/- SD: 0.325 +/- 0.112 in absorptive hypercalciuria; 0.533 +/- 235 in renal hypercalciuria). There was a significant difference in the composition of phosphate complexes between the 6 normocalciuric patients and the 6 children with renal hypercalciuria investigated. Lithogenic urinary phosphate complexes (CaHPO4, MgHPO4) were excreted by the latter group in a significantly higher amount under basal conditions. On the basis of these data sodium restriction added to low calcium diet could represent a dietary approach in preventing excessive calcium excretion in idiopathic hypercalciuria, and therefore renal stone formation.     

Clinical characteristics and metabolic abnormalities in preschool-age children with urolithiasis in southeast Anatolia

ObjectiveData on urolithiasis in preschool-age children are limited. The aim of this study was to investigate the metabolic etiology and clinical findings of preschool-age children with urolithiasis.MethodsThe medical records of 143 preschool-age children (81 boys, 62 girls, aged 2–6 years) with urolithiasis were retrospectively analyzed. Results of physical examination, serum biochemistry, and urine metabolic evaluation (including urinary citrate, oxalate, calcium, uric acid, cystine, and magnesium) were recorded.ResultsThe mean age at diagnosis was 3.7 ± 1.3 years. A family history of stone disease was found in 79.7% of patients, and 37% of parents had consanguineous marriages. The most common presenting symptoms were hematuria (33%) and urinary tract infection (UTI; 29%). Metabolic abnormalities were found in 119 (83.2%) patients, including hyperuricosuria in 24.5%, hypocitraturia in 23.8%, hyperoxaluria in 21.7%, hypercalciuria in 21.0%, cystinuria in 7.7%, and hypomagnesuria in 1.4%. Multiple metabolic abnormalities were found in 24 (16.8%) patients. Results of 28 stone analyses revealed calcium oxalate or phosphate, cystine, and uric acid in 15, nine, and four of the patients, respectively. ^99mTechnetium–dimercaptosuccinic acid renal scintigraphy revealed that 27.8% of the children with UTI had renal parenchymal scarring, with only four of them having vesicoureteral reflux.ConclusionThe most frequent metabolic abnormalities in preschool-age children with urolithiasis were hyperuricosuria and hypocitraturia. A comprehensive investigation of stone disease in children presenting with hematuria and UTI is important to prevent the development of renal parenchymal scarring.     

Bilateral urinary calculi after treatment with a silicate-containing milk thickener

Nephrocalcinosis and/or urinary calculi are rare in infants. Furosemide treatment during the neonatal period, vitamin D intoxication, hereditary diseases such as hyperoxaluria or distal tubular acidosis are among the most common aetiologies. We report the case of a 6-month-old boy with an extra-hepatic biliary duct atresia treated by the Kasai procedure and a gastro-oesophageal reflux treated with a silicate containing milk thickener (Gelopectose, 5.5% colloidal silicate) since the neonatal period. He did not present any other endogenous risk factor for urinary stone formation (normal urinary calcium/creatinine ratio; normal urinary magnesium excretion). The nephrolithiasis was discovered as the boy presented painful episodes of macroscopic haematuria. Ultrasound examination revealed bilateral nephrocalcinosis and multiple bilateral calculi without infection or urinary obstruction. Infrared spectroscopy revealed silicate as the major component suggesting silicate absorption to be responsible for the described symptoms. After replacement of the silicate-containing agent by a silicate-free milk thickener, the lesions were completely reversible as confirmed by repeated renal ultrasound examinations over a 2-month period. Conclusion:silicate-containing milk thickeners can be responsible for urinary calculi and/or nephrocalcinosis.     

Type I primary hyperoxaluria associated with type I renal tubular acidosis

An 8-year-old boy who had suffered from recurrent stone formation since the age of 4 years, was admitted as an emergency due to anuria for a half day on November 20, 1986. Kidney-ureter-bladder film showed that the urethra was obstructed by a stone, and emergent cystoscopy was performed to remove it. He is the product of consanguinous marriage, his parents being first cousins. There was no family history of renal stone. Laboratory investigations showed hypokalemic, hyperchloremic metabolic acidosis. The ammonium chloride loading test revealed inability to acidify the urine and a markedly decreased excretion of titrable hydrogen ion and ammonium ion in the urine. These results indicate that this is a case of Type I renal tubular acidosis. His 24-hour urinary excretion of oxalate and glyoxylate were also markedly increased. There were no underlying causes leading to the development of secondary hyperoxaluria. These results also establish the diagnosis of Type I primary hyperoxaluria. The patient then received regimens of Polycitra 1ml/kg/day and Vitamin B6 50mg/day for 4 months. However, urinary stone developed again in this patient 4 months later. To our knowledge, Type I primary hyperoxaluria in association with Type I renal tubular acidosis has not been previously reported.     

原发性高草酸尿症3型8例病例系列报告并文献复习

背景：原发性高草酸尿症（PH）是一种罕见的由于先天性肝内乙醛酸代谢异常导致的遗传性肾结石/肾钙质沉着症,既往多关注1型和2型PH,PH3的致病基因HOGA1发现较晚,报告不多。 目的：总结PH3临床表型,探讨不同种族人群的PH3热点变异。 设计：病例系列报告。 方法：纳入2015年1月至2021年12月复旦大学附属儿科医院经HOGA1基因变异确诊为PH3的连续病例。从住院病史中采集临床和生物学检测信息,在PubMed、Embase、万方数据库和中国知网数据库中检索PH3病例的中、英文文献,采集病例来源（国家）、例数、性别、起病年龄、诊断年龄、起病临床表现（尿石症、肾钙质沉着症、高钙尿症、高草酸尿症）、随访时间、肾功能（慢性肾脏病2期、3期、4~5期）、随访年龄、尿路结石转归 (活动性结石、无症状结石或结石消失)、HOGA1基因变异位点。 主要结局指标：临床表型和不同种族人群的热点变异。 结果：纳入8例PH3患儿,男7例,女1例;起病年龄中位数10月龄,诊断年龄中位数16月龄。3例以肉眼血尿起病,5例以泌尿道感染起病。影像学均提示肾结石,均无肾钙质沉着表现。3例检测了24 h尿草酸,1例提示高草酸尿症;6例检测了尿钙,5例提示高钙尿症。1例失访,7例随访中位时间25个月,肾小球滤过率均维持稳定,3例肾结石消失。8例均检出HOGA1基因变异（共10个变异位点）,其中复合杂合变异5例,纯合变异3例,经ACMG分级判定6个位点为可能致病变异,4个位点为致病变异。中英文数据库共检索到82篇文献,筛选后23篇文献中321例PH3患者进入本文分析,中国36例（包括本文8例）,欧美293例。中国和欧美PH3患者：起病表现为尿石症的比例分别为83%(30/36)和85%(195/230),肾钙质沉着症分别为3%(1/29)和8%(20/261),高草酸尿症分别为90%(26/29)和96%(66/69),差异均无统计学意义;高钙尿症分别为44%(11/25)和23%（34/150),差异有统计学意义;末次随访时肾功能：中国1例PH3患者25岁时进展至终末期肾病,欧美2例PH3患者分别在8岁和33岁进展至终末期肾病;活动性结石：中国和欧美PH3患者分别为13%(3/23)和37%(22/59),差异有统计学意义。中国PH3患者热点变异为c.834G>A (splice site)、c.834_c.834+1GG>TT (splice site)和c.769T＞G (p.C257G),分别占28%(20/72)、21%(15/72)和11%(8/72);欧美PH3患者热点变异为c.700+5G>T (splice site)和c.944_946delAGG(p.E315del),分别占40%(236/586)和12%(73/586)。 结论：PH3起病年龄和诊断年龄较早,整体预后较PH1和PH2良好,中国与欧美PH3患者HOGA1基因突变可能存在不同的热点变异位点。     

Etiologic and Epidemiologic Pattern of Urolithiasis in North Iran;Review of 10-Year Findings

Objective: To determine epidemiologic and metabolic characteristics of renal stone in the northern Iran. Methods: We prospectively analyzed demographic, clinical and metabolic findings in children less than 16 years old with renal stone revealed by ultrasonography from September 2003 to May 2012. Evaluations included serum and urine measurement of main elements predisposing patients to stone formation. Findings : 271 children (160 males) aged 2 months to 16-years (mean 30 months) were evaluated. 91 (33.6%) had a positive family history, abdominal discomfort (18.8%), UTI (11.8%) and hematuria (11.4%) were main presenting features. 45 children were diagnosed accidentally without any specific compliant. Nearly all (99%) stones lay in kidney., 35.1% had metabolic, 10% infective and 4.1% obstructive trends, 110 children had no definable etiology. Hypercalciuria (25.5%) hyperoxaluria (18.4%) and hypocitraturia (18.1%) were more frequent than uricosuria (8.5%) and cystinuria (3.1%) Conclusion: Metabolic derangement plays significant role in stone formation in our area. Patients should be carefully evaluated considering this point of view.Key Words: Nephrolithiasis, Kidney Stone, Hypercalciuria, Hyperoxaluria, Cystinuria, Hypocitraturia     

Epidemiology of paediatric renal stone disease in the UK.

BACKGROUND: The previous epidemiological study of paediatric nephrolithiasis in Britain was conducted more than 30 years ago. AIMS: To examine the presenting features, predisposing factors, and treatment strategies used in paediatric stones presenting to a British centre over the past five years. METHODS: A total of 121 children presented with a urinary tract renal stone, to one adult and one paediatric centre, over a five year period (1997-2001). All children were reviewed in a dedicated stone clinic and had a full infective and metabolic stone investigative work up. Treatment was assessed by retrospective hospital note review. RESULTS: A metabolic abnormality was found in 44% of children, 30% were classified as infective, and 26% idiopathic. Bilateral stones on presentation occurred in 26% of the metabolic group compared to 12% in the infective/idiopathic group (odds ratio 2.7, 95% CI 1.03 to 7.02). Coexisting urinary tract infection was common (49%) in the metabolic group. Surgically, minimally invasive techniques (lithotripsy, percutaneous nephrolithotomy, and endoscopy) were used in 68% of patients. CONCLUSIONS: There has been a shift in the epidemiology of paediatric renal stone disease in the UK over the past 30 years. Underlying metabolic causes are now the most common but can be masked by coexisting urinary tract infection. Treatment has progressed, especially surgically, with sophisticated minimally invasive techniques now employed. All children with renal stones should have a metabolic screen.     

Epidemiology of paediatric renal stone disease in the UK

Background: The previous epidemiological study of paediatric nephrolithiasis in Britain was conducted more than 30 years ago. Aims: To examine the presenting features, predisposing factors, and treatment strategies used in paediatric stones presenting to a British centre over the past five years. Methods: A total of 121 children presented with a urinary tract renal stone, to one adult and one paediatric centre, over a five year period (1997–2001). All children were reviewed in a dedicated stone clinic and had a full infective and metabolic stone investigative work up. Treatment was assessed by retrospective hospital note review. Results: A metabolic abnormality was found in 44% of children, 30% were classified as infective, and 26% idiopathic. Bilateral stones on presentation occurred in 26% of the metabolic group compared to 12% in the infective/idiopathic group (odds ratio 2.7, 95% CI 1.03 to 7.02). Coexisting urinary tract infection was common (49%) in the metabolic group. Surgically, minimally invasive techniques (lithotripsy, percutaneous nephrolithotomy, and endoscopy) were used in 68% of patients. Conclusions: There has been a shift in the epidemiology of paediatric renal stone disease in the UK over the past 30 years. Underlying metabolic causes are now the most common but can be masked by coexisting urinary tract infection. Treatment has progressed, especially surgically, with sophisticated minimally invasive techniques now employed. All children with renal stones should have a metabolic screen.     

Idiopathic hypercalciuria due to primary decrease in the renal tubular reabsorption of calcium. Hypercalciuria type 2 according to Bordier (author's transl)

A persistent hypercalciuria and normal serum levels of calcium were measured in a 5-year-old boy suffering from recurrent macro- and microhaematuria and bilateral nephrolithiasis (stone analysis was positive for calcium-oxalate). No growth retardation or any other relevant clinical parameters concerning hypercalciuria e.g. vitamin D-intoxication or renal tubular acidosis could be observed. A slight secondary hyperparathyroidism and increased calcium excretion during fasting or calcium depleted diet indicates a primary failure of calcium reabsorption as previously described by Bordier (hypercalciuria type 2). Treatment with a combination of hydrochlorothiazide (Esidrix) and sodium chloride depleted diet resulted in a long-lasting normalization of calcium excretion and thus disappearance of symptoms in the child.     

Urinary outputs of oxalate,calcium, and magnesium in children with intestinal disorders. Potential cause of renal calculi.

24-hour urinary outputs of oxalate, calcium, and magnesium have been determined in a total of 62 children aged 3 months to 17 years who fell into the following groups: (i) 16 normal controls, (ii) 3 with primary hyperoxaluria, (iii) 9 with small and/or large intestinal resections, (iv) 9 with untreated coeliac disease, (v) 5 with pancreatic dysfunction, and (vi) a miscellaneous group of 20 children with a variety of intestinal disorders. Taken as a whole, 58% of patients with intestinal disorders had hyperoxaluria, and of these 7% had urinary outputs of oxalate which fell within the range seen in primary hyperoxaluria. The proportion of children with hyperoxaluria in the different diagnostic groups was as follows: intestinal resections (78%), coeliac disease (67%), pancreatic dysfunction (80%), and miscellaneous (45%). 35% of the patients with hyperoxaluria had hypercalciuria, whereas magnesium excretion was normal in all subjects studied. In 2 patients treatment of the underlying condition was accompanied by a return of oxalate excretion to normal. These results indicate that hyperoxaluria and hypercalciuria are common in children with a variety of intestinal disorders, and that such children may be at risk of developing renal calculi without early diagnosis and treatment.     

Urinary outputs of oxalate, calcium, and magnesium in children with intestinal disorders. Potential cause of renal calculi

24-hour urinary outputs of oxalate, calcium, and magnesium have been determined in a total of 62 children aged 3 months to 17 years who fell into the following groups: (i) 16 normal controls, (ii) 3 with primary hyperoxaluria, (iii) 9 with small and/or large intestinal resections, (iv) 9 with untreated coeliac disease, (v) 5 with pancreatic dysfunction, and (vi) a miscellaneous group of 20 children with a variety of intestinal disorders. Taken as a whole, 58% of patients with intestinal disorders had hyperoxaluria, and of these 7% had urinary outputs of oxalate which fell within the range seen in primary hyperoxaluria. The proportion of children with hyperoxaluria in the different diagnostic groups was as follows: intestinal resections (78%), coeliac disease (67%), pancreatic dysfunction (80%), and miscellaneous (45%). 35% of the patients with hyperoxaluria had hypercalciuria, whereas magnesium excretion was normal in all subjects studied. In 2 patients treatment of the underlying condition was accompanied by a return of oxalate excretion to normal. These results indicate that hyperoxaluria and hypercalciuria are common in children with a variety of intestinal disorders, and that such children may be at risk of developing renal calculi without early diagnosis and treatment.     

Idiopathic hypercalciuria: presentation of 471 cases

OBJECTIVE: To analyze the clinical history and evolution of children and adolescents with IH, emphasizing some of their peculiar features. METHODS: We followed 471 patients with IH at an outpatient clinic. Patients were submitted to the following protocol: abdominal X-ray, kidney and urinary tract ultrasonography; urinary ionogram, blood gas and biochemical analyses; 24-hour urine for measurement of calcium and other electrolytes and creatinine; urinalysis, urine culture and phase-contrast microscopy; second morning urine collected after fasting for measurement of calcium and creatinine. RESULTS: At the time of diagnosis, 6% of the patients were infants, 15% pre-school children, 55% school children, and 24% adolescents; 56% of them were boys. Clinical and laboratory findings were: 47% had hematuria and abdominal pain, 31% had isolated hematuria, 14% isolated abdominal pain, and 8% had urinary tract infection, nocturnal enuresis, suprapubic pain or urethralgia, or the frequency/urgency syndrome with urinary incontinence. Hypercalciuria was associated with urolithiasis in 56% of patients. There was association with hyperuricosuria in 18.5% of the cases, and hypocitraturia in 8.5% of the cases. Evolution was poor for 33% of the patients, with recurrence of nephrolithiasis, persistence of hematuria, and abdominal pain. CONCLUSIONS: IH must be diagnosed and treated with criteria in order to reduce consequences such as hematuria, abdominal pain, urinary stone formation and possible bone involvement. Signs and symptoms such as urgency and urinary incontinence, suprapubic pain and nocturnal enuresis may result from renal hyperexcretion of calcium.     

An association between kidney stone composition and urinary metabolic disturbances in children

ObjectiveTo determine kidney stone composition in children and to correlate stone fractions with urinary pH and metabolic urinary risk factors.Patients and methodsWe studied 135 pediatric patients with upper urinary tract lithiasis in whom excreted or extracted stones were available for analyses. Composition of stones was analyzed. A 24-hour urine assessment included volume, pH and daily excretions of calcium, oxalate, uric acid, cystine, creatinine, phosphate, magnesium and citrate.ResultsCalcium oxalate was the major component of 73% stones, followed by struvite (13%) and calcium phosphate (9%). Uric acid was present in almost half of stones, but in rudimentary amounts. The calcium oxalate content in calculi showed a strong relationship with calciuria, and moderate association with oxaluria, magnesuria and acidification of urine. The percent content of struvite presented reverse and lower correlations with regard to the above parameters. Calcium phosphate stone proportion had low associations with urinary risk factors.ConclusionsCalciuria, oxaluria, magnesuria and low urine pH exerted the biggest influence on calcium oxalate content in pediatric renal stones. Relationships of urinary risk factors with calculi calcium phosphate content were of unclear significance. Urinary citrate excretion did not significantly correlate with kidney stone composition in children.     

Urinary citrate excretion in idiopathic nephrolithiasis

OBJECTIVE: To determine urinary citrate excretion in children with nephrolithiasis and normal controls. DESIGN: Prospective. SETTING: Tertiary care center in New Delhi. METHODS: This study was done on 50 children, below the age of 12 years, with idiopathic urinary calculi and 150 age and weight matched controls. The children were divided into 3 groups: Group 1 (1-4 years), Group 2 (5-8 years) and Group 3 (9-12 years). Urinary citrate was estimated in a 24-hour urine sample using colorimetric method. The stones removed from these children were also analysed. RESULTS: There was a preponderance of urinary stones in males; the highest incidence being in Group 1. Excretion of citrate in 24-hour urine sample was significantly lower in patients compared to controls, for males in all age groups and for females in Group 3. However, there was no statistically significant difference in the urinary citrate value between males and females in a given age group for either controls or patients. The urinary citrate excretion increased with age in patients and controls, but the levels in patients were lower. Depending upon the constituents, four types of stones were identified, calcium phosphate, calcium oxalate, uric acid and magnesium ammonium phosphate. Nine stones had at least more than one major constituent. Hypocitraturia was detected in 43 percent cases. The incidence was 76 percent for calcium phosphate, 87 percent for calcium oxalate, 40 percent for uric acid stones and 50 percent for magnesium ammonium phosphate. CONCLUSION: This study shows that low urinary citrate is associated with urinary stones in children, especially in endemic areas, in the absence of obvious etiological factors. Urinary citrate excretion should be determined in all children with nephrolithiasis.     

Intracraneal epidural abscess as a complication of sinusitis

Familiar hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare syndrome belonging to the group of heterogeneous tubular diseases whose common characteristic is renal magnesium wasting. We present a 9 year old boy with polyuria, polydipsia and enuresis. Radiologic and ultrasonographic examinations showed nephrocalcinosis. Hypomagnesemia, normokaliemia, hypermagnesiuria, hypercalciuria, incomplete distal tubular acidosis, hypocitraturia and mild renal failure were found. Treatment with magnesium salts, hydrochlorothiazide, potassium citrate and sodium bicarbonate did not restore magnesium or calcium levels to normal. Renal function and nephrocalcinosis remain stable after 3 year's treatment. In conclusion, we report a new case of this rare syndrome caused by a congenital defect in magnesium reabsorption and discuss the evolution of the illness during 3 years' treatment.     

Primary hyperoxaluria type 2

Primary hyperoxaluria type 2 (PH2) is a rare disease with only 24 patients reported in the literature so far. It should be considered in any patient presenting with urolithiasis or nephrocalcinosis due to hyperoxaluria. The metabolic defect is deficiency of d-glycerate dehydrogenase/glyoxylate reductase leading to characteristic hyperoxaluria and excretion of l-glycerate, the cornerstone of diagnosis of PH 2. Although development of terminal renal failure seems to be less prevalent than in PH 1, recent reports indicate that chronic as well as terminal renal insufficiency may occur. Therefore specific therapeutic measures should aim at reduction of urinary calcium oxalate saturation by potassium citrate or pyrophosphate to reduce the incidence of nephrolithiasis and nephrocalcinosis and thus improve renal survival. Secondary complications (obstruction, urinary tract infections and pyelonephritis) must be avoided. In patients with terminal renal failure isolated renal transplantation seems to carry a high risk of disease recurrence. Conclusion PH 2 is a rare but important cause of urolithiasis and nephrocalcinosis; long-term follow up is necessary, since the renal prognosis may be worse than previously anticipated. Received: 22 November 1996 / Accepted: 17 January 1997     

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

ObjectiveTo provide insight in causative factors of pediatric urolithiasis in The Netherlands, a non-endemic country.Patients and methodsData 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.ResultsOf 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.ConclusionChildren 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.