Pediatric urolithiasis.

Pediatric stone disease is a frequently underestimated entity that can present unique problems in its management. The condition stems from any of a number of underlying, causative factors, and the significant possibility of recurrence must always be borne in mind. The primary care physician should be aware that the condition is readily treatable by an experienced pediatric urologist who has a range of treatment modalities at his or her disposal; however, overall success is governed by a timely referral and subsequent long-term follow-up to ensure the maintenance of a stone-free state.     

Pediatric urolithiasis with renal failure: Siut experience

PurposePediatric urolithiasis is endemic in Pakistan and constitutes about 13% of all urolithiasis cases. Urolithiasis associated with renal failure is one of the most important cause of pediatric ESRD in Pakistan.Material and methodsRetrospective analysis of 402 children with urolithiasis and associated renal failure. Ultrasound was the mainstay of radiological diagnosis and assessment.Results402 patients, age ranged between 9 months to 14 years with male female ratio of 2:1. More than 50% had a positive family history of stone disease. Apart from obstruction and infection, poor socioeconomic status (89%), rural residence (66%), neglect and delay in acquiring treatment led to renal failure in these patients. The most common signs and symptoms were fever (56.7%), flank pain (55.2%), shortness of breath (38%) and vomiting (38.3%). 105 (26%) were anuric at presentation and 297 (74%) non-anuric. More than 60% of these patients had bilateral stones and associated urinary tract infection. The initial management of these patients required dialysis mostly peritoneal dialysis in small children. Percutaneous nephrostomy with or with out dialysis was also the main stay of initial management especiallyfor those presenting with a pyonephrosis. In some “Double J” stents were also placed to relieve obstruction. Details of operative procedures for definitive treatment and type of stones will be provided in presentation.ConclusionsAbout 70% of the patients had good recovery of renal function. These good results were achieved because of the provision of free high technological treatment to all our patients under one roof with close co-operation of pediatric urology, nephrology and intensive care teams.     

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.     

Nutcracker syndrome with urolithiasis

The nutcracker syndrome, caused by compression of the left renal vein between the superior mesenteric artery and the aorta, usually manifests with hematuria, flank pain and proteinuria. We report on a 9-year-old boy who was previously diagnosed with urolithiasis but had significant proteinuria, not explained by this diagnosis. On further investigation by renal Doppler ultrasonography it was found that he had nutcracker syndrome. We would like to emphasize that this syndrome should be considered where there is no obvious cause of proteinuria and hematuria.     

Surgical management of urolithiasis

Pediatric patients with urolithiasis present unique challenges. Interventional techniques developed for adult patients have been adopted and adapted to facilitate effective and safe treatment in this population. Management must be stratified and individualized, taking into account the many factors described in this article. Long-term follow-up and metabolic evaluation are essential components of the overall treatment strategy. Interventional management will continue to evolve with progressive refinements in instrumentation and techniques.     

Hypocitraturia in patients with urolithiasis

The urinary citrate/creatinine ratio was evaluated in 25 children with idiopathic calcium urolithiasis and 24 controls. The mean (SD) urinary citrate/creatinine ratio in controls and patients was 0.510 (0.205) and 0.181 (0.076), respectively, a statistically significant difference. In neither group was there a relation between age and urinary citrate excretion.     

Urinary glycosaminoglycan excretion in urolithiasis

Urinary glycosaminoglycan (GAG) excretion was measured inchildren with idiopathic urolithiasis (15 girls and 10 boys; mean (SD)age 6.2 (2.4) years) and in healthy controls (10 girls and 14 boys;mean (SD) age 6.8 (3.8) years). GAG excretion was expressed as aGAG/creatinine (mg/g) ratio and was evaluated using dimethylmethylene blue. In healthy control children, the mean (SD) GAG/creatinine ratiowas 31.67 (12.76) and it was similar in girls and boys. The childrenwith idiopathic urolithiasis had significantly lower mean (SD)GAG/creatinine ratios than controls (22.59 (7.35)). Therefore, urinaryGAG excretion may be important in the disease process in children withurolithiasis, as it is in adults.

     

Urinary glycosaminoglycan excretion in urolithiasis.

Urinary glycosaminoglycan (GAG) excretion was measured in children with idiopathic urolithiasis (15 girls and 10 boys; mean (SD) age 6.2 (2.4) years) and in healthy controls (10 girls and 14 boys; mean (SD) age 6.8 (3.8) years). GAG excretion was expressed as a GAG/creatinine (mg/g) ratio and was evaluated using dimethylmethylene blue. In healthy control children, the mean (SD) GAG/creatinine ratio was 31.67 (12.76) and it was similar in girls and boys. The children with idiopathic urolithiasis had significantly lower mean (SD) GAG/creatinine ratios than controls (22.59 (7.35)). Therefore, urinary GAG excretion may be important in the disease process in children with urolithiasis, as it is in adults.     

Medical evaluation and treatment of urolithiasis

Nephrolithiasis is responsible for 1 in 1000 to 1 in 7600 pediatric hospital admissions annually throughout the United States. Seventy-five percent of children with nephrolithiasis have an identifiable predisposition to stone formation. This article reviews the different causes and disease states associated with nephrolithiasis in the pediatric population. The initial evaluation and the metabolic evaluation of children with nephrolithiasis are reviewed. Treatment modalities for the different stone types are also described.     

Childhood urolithiasis: experiences and advances

Between June 1979 and June 1989, 54 children with urolithiasis were evaluated and treated at the Johns Hopkins Children's Center. The most common symptoms were flank or abdominal pain (58%) and gross hematuria (28%). In 46 children (86%), stones were secondary to a preexisting condition and in only 8 (14%) no apparent cause of stone formation could be found. Thirty-six patients (66%) had a solitary stone, most commonly found in the kidney. Urinary tract infections were present in 25 (47%) of the patients who had stones. Stones composed either of calcium oxalate or struvite were the most frequently recovered in these patients with infections. Twenty-one patients (39%) spontaneously passed their stones whereas 23 (43%) required either surgery or extracorporeal shock-wave lithotripsy to resolve stones. Ten (20%) showed recurrence of their urolithiasis, with follow-up examination periods ranging from 1 month to 10 years. Recent advances in the management of urolithiasis and their applicability to the pediatric population are discussed.     

Hypocitraturia in patients with urolithiasis.

The urinary citrate/creatinine ratio was evaluated in 25 children with idiopathic calcium urolithiasis and 24 controls. The mean (SD) urinary citrate/creatinine ratio in controls and patients was 0.510 (0.205) and 0.181 (0.076), respectively, a statistically significant difference. In neither group was there a relation between age and urinary citrate excretion.     

Uric acid excretion in children with urolithiasis

Urinary uric acid excretion was assessed in 38 children to determine whether hyperuricuria was a risk factor in children with urolithiasis. Uric acid excretion (measured per deciliter glomerular filtration rate), and fractional excretion of uric acid were similar in 27 children with hypercalciuria and calcium oxalate urinary stones, in six children with idiopathic calcium oxalate urolithiasis, and in five with uric acid urolithiasis, of whom four were white boys and one was an Asian girl. One boy with a urate stone had cystinosis. Serum uric acid concentrations exceeded 6.0 mg/dl (360 mumol/L) in two children with hypercalciuria and in two patients with idiopathic calcium oxalate urolithiasis. None of the children with calcium urolithiasis had excessive urinary excretion of uric acid. In children with hypercalciuria, uric acid excretion did not change significantly when dietary sodium was increased from 1.0 to 5.0 gm/1.73 m2. We conclude that excessive urinary uric acid excretion is seldom an additional risk factor in children with calcium urolithiasis and that dietary sodium chloride does not have a strong influence on urinary excretion of uric acid in children with hypercalciuria.     

Urinary oxalate excretion in urolithiasis and nephrocalcinosis

AIMS—To investigate urinary oxalate excretion in children with urolithiasis and/or nephrocalcinosis and to classify hyperoxaluria (HyOx).METHODS—A total of 106 patients were screened. In those in whom the oxalate: creatinine ratio was increased, 24 hour urinary oxalate excretion was measured. Liver biopsy and/or genomic analysis was performed if primary hyperoxaluria (PH) was suspected. Stool specimens were examined for Oxalobacter formigenes in HyOx not related to PH type 1 or 2 (PH1, PH2) and in controls.RESULTS—A total of 21 patients screened had HyOx (>0.5 mmol/24 h per 1.73 m²); they were classified into five groups. Eleven had PH (PH1 in nine and neither PH1 nor PH2 in two). Six had secondary HyOx: two enteric and four dietary. Four could not be classified. Seven patients had concomitant hypercalciuria. Only one of 12 patients was colonised with O formigenes compared to six of 13controls.CONCLUSIONS—HyOx is an important risk factor for urolithiasis and nephrocalcinosis in children, and can coexist with hypercalciuria. A novel type of PH is proposed. Absence of O formigenes may contribute to HyOx not related to PH1.     

儿童泌尿系结石的诊断和治疗

在泌尿系结石患者中,儿童患者约占2%～3%~([1]).小儿泌尿系结石的发病率有其特点,如地区性、经济状况等.关于儿童泌尿系结石的发病率,尚缺乏可靠的统计学数据,VanDervoort等~([2])报道在一个医疗机构中,1994至2005年间泌尿系结石患儿所占住院患儿的比例增加了5倍.