Effect of potassium citrate therapy on stone recurrence and regrowth after extracorporeal shockwave lithotripsy in children

Contemporary minimal invasıve surgical management of stones in children

Objective

Pediatric urolithiasis has been more common over the past 20 years, and urologists have unique challenges in managing it surgically because this particular demographic is recognized as one of the high-risk categories for stone recurrence. Given this reality, care focuses on maintaining renal function, achieving total stone-free status, and most importantly avoiding stone recurrences. In this presented article, we aimed to make a comprehensive review of the current minimally invasive treatment of pediatric kidney stone disease.

Methods

We evaluated the results of 74 studies following a comprehensive PubMed search till February 2023. This article was written by making use of current urology guidelines.

Results

Considering the reported occurrence of metabolic issues in up to 50% of cases in addition to the anatomic anomalies (about 30% of cases), the treatment of pediatric urolithiasis necessitates a full metabolic and urological examination on an individual basis. Timely management of metabolic imbalances and obstructive diseases is necessary. In addition to encouraging proper fluid consumption, it is advisable to improve urine volume and consider using medical therapeutics to raise urinary citrate levels. The location, content, and size of the stone(s), the morphology of the collecting system, the presence of urinary tract infection, as well as the presence of any obstruction, should all be taken into consideration while deciding on the best surgical procedure.

Conclusion

All modern endourological methods are now used in the safe and efficient care of pediatric urolithiasis as a consequence of the obvious advancements in instrument technology and expanding expertise derived from adult patients. Other minimally invasive procedures, such as ureterorenoscopy and percutaneous nephrolithotomy, require more expertise and can be successfully applied with careful management for an excellent stone-free rate with minimal morbidity. Of these procedures, shock wave lithotripsy is still the first choice in the majority of cases with upper tract calculi. Open surgery will still be the therapy of choice for pediatric patients with complicated and big stones as well as anatomical anomalies.

Dietary management of hypocitraturia in children with urolithiasis: results from a systematic review

PURPOSE

Hypocitraturia is a low urinary excretion of citrate and a well-known risk factor for kidney stone development in children. This systematic review aimed to evaluate the dietary management of hypocitraturia in children with urolithiasis.

METHODS

Literature search was performed on 30th September 2022 using Embase, PubMed, and Cochrane Central Controlled Register of Trials. Studies were included if children with stones and hypocitraturia were managed with diet supplements.

RESULTS

Six papers were included. Four studies evaluated the role of oral potassium citrate associated with high fluid intake on stone resolution and recurrence. Two studies assessed the impact of oral potassium citrate on long-term stone recurrence after percutaneous nephrolithotomy and shock wave lithotripsy. All studies demonstrated that the association of potassium citrate and high fluid intake was well tolerated with no side effects and restored normal urine citrate excretion, allowed a reduction in stone size, and, following definitive treatments, was associated with a lower rate of stone regrowth and recurrence compared with controls. These effects were demonstrated across all pediatric ages.

CONCLUSIONS

Our review infers that oral potassium citrate and high fluid assumption are safe and effective in restoring urine citrate excretion, treating and preventing stone recurrence with no serious adverse events, and should probably be the first-line treatment of pediatric patients with asymptomatic stones and hypocitraturia.

The current status of preventive measures for urinary calculi in children

Urological calculus is a common disease in urology. Urological calculi are generally more common in adults but have become more common in children in recent years. Most existing studies focus on the prevention of urinary calculi in adults; there are relatively few articles on calculi in children. Reported preventive measures are not comprehensive enough, while the latest research progress has not been updated. The pathogenesis and preventive measures associated with urinary calculi have been the focus of research, but many preventive measures still need further clarification. This article reviews the progress on preventive measures for urinary calculi in children.

Should pediatric idiopathic hypercalciuria be treated with hypocalciuric agents?

BACKGROUND

Hypercalciuria is the most common metabolic risk factor for calcium urolithiasis and is associated with bone loss in adult patients. Reduced bone mineral density (BMD) was already described in idiopathic hypercalciuria (IH) children, but the precise mechanisms of bone loss or inadequate bone mass gain remain unknown. Life-long hypercalciuria might be considered a risk to change bone structure and determine low bone mass throughout life. The peak of bone mass should occur without interferences. A beneficial effect of citrate formulations and thiazides on bone mass in adult and pediatric patients with IH have been shown.

AIM

To evaluate whether pharmacological therapy has a beneficial effect on bone mass in children and adolescents with IH.

METHODS

This retrospective cohort study evaluated 40 hypercalciuric children non-responsive to lifestyle and diet changes. After a 2-mo run-in period of citrate formulation (Kcitrate) usage, the first bone densitometry (DXA) was ordered. In patients with sustained hypercalciuria, a thiazide diuretic was prescribed. The second DXA was performed after 12 mo. Bone densitometry was performed by DXA at lumbar spine (L2-L4). A 24-h urine (calcium, citrate, creatinine) and blood samples (urea, creatinine, uric acid, calcium, phosphorus, magnesium, chloride, hemoglobin) were obtained. Clinical data included age, gender, weight, height and body mass index.

RESULTS

Forty IH children; median age 10.5 year and median time follow-up 6.0 year were evaluated. Nine patients were treated with Kcitrate (G1) and 31 with Kcitrate + thiazide (G2). There were no differences in age, gender, body mass index z-score and biochemical parameters between G1 and G2. There were no increases in total cholesterol, kalemia and magnesemia. Calciuria decreased in both groups after treatment. Lumbar spine BMD z-score increased after thiazide treatment in G2. There was no improvement in G1.

CONCLUSION

Results point to a beneficial effect of thiazide on lumbar spine BMD z-score in children with IH. Further studies are necessary to confirm the results of the present study.

Phytotherapy and Herbal Medicines for Kidney Stones

BACKGROUND

Kidney stones are one of the longest known and most common diseases in the urinary tract, with a prevalence that ranges from 1% to 20%. Many phytotherapeutic and herbal medicines have been described for the treatment and prevention of kidney stones.

OBJECTIVE

The aim of this study was to perform a comprehensive review of publications on various phytotherapeutic and herbal medicines, including both clinical and animal studies.

RESULTS

Phytotherapy may influence the risk of recurrence of calcium oxalate and uric acid stones. The most solid evidence relates to Phyllanthus niruri, one of the most studied phytotherapeutics; findings suggest that it interferes with calcium oxalate crystallization, reduces hyperoxaluria and hyperuricosuria, and increases the efficacy of shock wave lithotripsy due to reduced crystallization, without significant adverse effects. Theobromine has been shown to reduce the crystallization of uric acid in patients and appears to be a promising supplement to treat such stones.

CONCLUSION

Many phytotherapeutic and herbal agents have been studied for the treatment of urolithiasis, most of them only in a small number of patients or in animal models. Further randomized clinical trials are needed to evaluate the effects of these agents on kidney stones.

Nephrolithiasis: Approach to Diagnosis and Management

Although kidney stones are less common in children than in adults, incidence in children is rising. Kidney stones may lead to significant morbidity in addition to escalating medical costs. Clinical presentation is variable. Bilateral kidney stones in a younger child should prompt work-up for primary hyperoxaluria. Metabolic abnormalities are more frequent in children and can result in frequent stone recurrence. Whole exome sequencing data shows genetic defects in about 30% of stone formers. 24 h urine collection should be conducted when patient receives his usual diet and fluid intake with normal activity. Infrared spectroscopy and X-ray diffraction are used for stone analysis. Urine studies should be delayed by 4-6 wk after stone fragmentation or treatment of any stone related complications. The goal of evaluation is to identify modifiable risk factors for which targeted therapy may be instituted. Primary indications for surgical intervention include pain, infection and obstruction. Extracorporeal shockwave lithotripsy (ESWL), ureteroscopy, and percutaneous nephrolithotomy (PCNL) are most commonly used, and selection is based on stone size, anatomy, composition and anatomy. Advances in technology have allowed a shift to minimally invasive surgeries. Comprehensive management requires multidisciplinary team. Children with kidney stones require long term follow-up with periodic assessment of stone forming activity and ascertaining stone burden. High index of suspicion should be there to diagnose diseases like primary hyperoxaluria, Dent's disease, renal tubular acidosis (RTA) etc. as these diseases have ramifications on kidney function and growth.

Prevention of recurrent urinary stone disease

PURPOSE OF REVIEW

Urinary stone disease (USD) is increasing in prevalence and recurrence is common. In pediatrics, most stones are composed primarily of calcium with the highest incidence observed in adolescents. Given the morbidity associated with USD, an in depth review of current management strategies is of paramount importance to highlight the data supporting the recommended treatments and the knowledge gaps which still exist.

RECENT FINDINGS

Several interventions for the management of recurrent calcium USD in children have been recommended based on primarily adult studies. These interventions include modification of diet and fluid intake in addition to the utilization of medications such as thiazide diuretics and citrates when supportive care is inadequate. Overall there is conflicting data in the adult literature which is further complicated by our attempts to extrapolate these data to children.

SUMMARY

Based on the currently available literature the management of USD in pediatrics should be individualized to each patient and focused on the particular metabolic risk factors that are identified during the course of their evaluation. Several interventions may be required or trialed in a particular patient to show an effect. Well designed trials to assess the efficacy of each intervention in the pediatric population are needed.

Medical treatment of urinary stones

PURPOSE OF REVIEW

To identify the latest progression on medical treatment of urinary stones.

RECENT FINDINGS

Nonsteroidal anti-inflammatory drugs should be the preferred analgesic option for patients presenting to the emergency department with renal colic. A-blockers could be of patient benefit when used for distal ureteral stones more than 5 mm in size. However, the quality of the randomized controlled studies on medical expulsive therapy (MET) is still low based on the Consolidated Standards for Reporting Trials (CONSORT) criteria. MET should be used with caution in children and pregnant women. In patients with renal stones, the evaluation of the comorbidities of developing chronic Kidney Disease (CKD) or End Stage Renal Disease (ESRD) is mandatory. It is highly recommended to follow the European Association of Urology Urolithiasis Guidelines Panel Diagnostic and Therapeutic algorithms to prevent stone recurrence.

SUMMARY

Medical treatment of urinary stone disease should be supported by well designed higher level of evidence clinical research.

Medical and dietary interventions for preventing recurrent urinary stones in children

BACKGROUND

Nephrolithiasis, or urinary stone disease, in children causes significant morbidity, and is increasing in prevalence in the North American population. Therefore, medical and dietary interventions (MDI) for recurrent urinary stones in children are poised to gain increasing importance in the clinical armamentarium.

OBJECTIVES

To assess the effects of medical and dietary interventions (MDI) for the prevention of idiopathic urinary stones in children aged from one to 18 years.

SEARCH METHODS

We searched multiple databases using search terms relevant to this review, including studies identified from the Cochrane Central Register of Controlled Trials (CENTRAL, 2017, Issue 1), MEDLINE OvidSP (1946 to 14 February 2017), Embase OvidSP (1980 to 14 February 2017), International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov. Additionally, we handsearched renal-related journals and the proceedings of major renal conferences, and reviewed weekly current awareness alerts for selected renal journals. The date of the last search was 14 February 2017. There were no language restrictions.

SELECTION CRITERIA

Randomized controlled trials of at least one year of MDI versus control for prevention of recurrent idiopathic (non-syndromic) nephrolithiasis in children.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane. Titles and abstracts were identified by search criteria and then screened for relevance, and then data extraction and risk of bias assessment were carried out. We assessed the quality of evidence using GRADE.

MAIN RESULTS

The search identified one study of 125 children (72 boys and 53 girls) with calcium-containing idiopathic nephrolithiasis and normal renal morphology following initial treatment with shockwave lithotripsy (SWL). Patients were randomized to oral potassium citrate 1 mEq/kg per day for 12 months versus no specific medication or preventive measure with results reported for a total of 96 patients (48 per group). This included children who were stone-free (n = 52) or had residual stone fragments (n = 44) following SWL. Primary outcomes:Medical therapy may lower rates of stone recurrence with a risk ratio (RR) of 0.19 (95% confidence interval (CI) 0.06 to 0.60; low quality evidence). This corresponds to 270 fewer stone recurrences per 1000 (133 fewer to 313 fewer) children. We downgraded the quality of evidence by two levels for very serious study limitations related to unclear allocation concealment (selection bias) and a high risk of performance, detection and attrition bias. While the data for adverse events were incomplete, they reported that six of 48 (12.5%) children receiving potassium citrate left the trial because of adverse effects. This corresponds to a RR of 13.0 (95% CI 0.75 to 224.53; very low quality evidence); an absolute effect size estimate could not be generated. We downgraded the quality of evidence for study limitations and imprecision.We found no information on retreatment rates.

SECONDARY OUTCOMES

We found no evidence on serum electrolytes, 24-hour urine collection parameters or time to new stone formation.We were unable to perform any preplanned secondary analyses.

AUTHORS' CONCLUSIONS

Oral potassium citrate supplementation may reduce recurrent calcium urinary stone formation in children following SWL; however, our confidence in this finding is limited. A substantial number of children stopped the medication due to adverse events. There is no trial evidence on retreatment rates. There is a critical need for additional well-designed trials in children with nephrolithiasis.

Kidney Stone Recurrence among Children and Adolescents

PURPOSE

Kidney stone disease has become increasingly common during childhood and adolescence. However, the rate of symptomatic kidney stone recurrence for pediatric patients is uncertain. We sought to determine the recurrence rate of symptomatic kidney stones in a cohort of children with incident symptomatic nephrolithiasis.

MATERIALS AND METHODS

We performed a retrospective cohort study of patients 3 to 18 years old without anatomical abnormalities or genetic causes of nephrolithiasis who presented with a first symptomatic kidney stone between 2008 and 2014. We determined recurrence rates of symptomatic nephrolithiasis, defined as a new kidney stone on ultrasound and/or computerized tomogram associated with pain and/or vomiting. We also estimated associations between completing 24-hour urinalysis and symptomatic kidney stone recurrence using Kaplan-Meier curves and multivariable Cox regression models.

RESULTS

A total of 285 children with a median age of 14.8 years (IQR 11.3-16.6) at nephrolithiasis diagnosis were followed for 492 person-years. A total of 86 symptomatic recurrent stones developed in 68 patients (24%) during the followup period. The probability of symptomatic stone recurrence was 50% at 3 years after the index kidney stone. Median time to stone recurrence was 3 years at the first recurrence and 5 years at the second. Adjusting for confounders including adherence to followup, completing a 24-hour urinalysis after a kidney stone episode was associated with a 60% decreased risk of recurrence (hazard ratio 0.40, 95% CI 0.18-0.91).

CONCLUSIONS

The risk of kidney stone recurrence is high during childhood, with approximately 50% of children presenting with symptomatic recurrence within 3 years of the first stone. The role and usefulness of analyzing 24-hour urine chemistries in decreasing kidney stone recurrence should be explored in future prospective studies.

Pediatric Kidney Stones - Avoidance and Treatment

Pediatric stone disease is increasing in incidence and healthcare costs. With more years at-risk for stone recurrence during their lifetimes, children with nephrolithiasis constitute a high-risk patient population that requires focused intervention through both medical and surgical means. Through high-quality future studies to compare methods of stone prevention and treatment, the burden of stone disease on the youngest members of society may be ameliorated.

Citrate salts for preventing and treating calcium containing kidney stones in adults

BACKGROUND

Kidney stones affect people worldwide and have a high rate of recurrence even with treatment. Recurrences are particularly prevalent in people with low urinary citrate levels. These people have a higher incidence of calcium phosphate and calcium oxalate stones. Oral citrate therapy increases the urinary citrate levels, which in turn binds with calcium and inhibits the crystallisation thus reduces stone formation. Despite the widespread use of oral citrate therapy for prevention and treatment of calcium oxalate stones, the evidence to support its clinical efficacy remains uncertain.

OBJECTIVES

The objective of this review was to determine the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 29 July 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that assessed the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones in adults treated for a minimum of six months.

DATA COLLECTION AND ANALYSIS

Two authors assessed studies for inclusion in this review. Data were extracted according to predetermined criteria. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included seven studies that included a total of 477 participants, most of whom had oxalate stones. Of these, three studies (247 participants) compared potassium citrate with placebo or no intervention; three (166 participants) compared potassium-sodium citrate with no intervention; and one (64 participants) compared potassium-magnesium citrate with placebo. Overall, quality of the reporting of the included studies was considered moderate to poor, and there was a high risk of attrition bias in two studies.Compared with placebo or no intervention, citrate therapy significantly reduced the stone size (4 studies, 160 participants: RR 2.35, 95% CI 1.36 to 4.05). New stone formation was significantly lower with citrate therapy compared to control (7 studies, 324 participants: RR 0.26, 95% CI 0.10 to 0.68). The beneficial effect on stone size stability was also evident (4 studies, 160 participants: RR 1.97, 95% CI 1.19 to 3.26). Adverse events were reported in four studies, with the main side effects being upper gastrointestinal disturbance and one patient reported a rash. There were more gastrointestinal adverse events in the citrate group; however this was not significant (4 studies, 271 participants: RR 2.55, 95% CI 0.71 to 9.16). There were significantly more dropouts due to adverse events with citrate therapy compared to control (4 studies, 271 participants: RR 4.45, 95% CI 1.28 to 15.50). The need for retreatment was significantly less with citrate therapy compared to control (2 studies, 157 participants: RR 0.22, 95% CI 0.06 to 0.89).

AUTHORS' CONCLUSIONS

Citrate salts prevent new stone formation and reduce further stone growth in patients with residual stones that predominantly contain oxalate. The quality of reported literature remains moderate to poor; hence a well-designed statistically powered multi-centre RCT is needed in order to answer relevant questions concerning the efficacy of citrate salts.

Evaluation and medical management of kidney stones in children

PURPOSE

We review the current literature on the diagnostic evaluation and dietary and pharmacological management of children with nephrolithiasis.

MATERIALS AND METHODS

We searched MEDLINE(®), Embase(®) and the Cochrane Library from their inceptions to March 2014 for published articles in English on kidney stones and therapy in children 0 to 18 years old. Based on review of the titles and abstracts, 110 of the 1,014 articles (11%) were potentially relevant to the diagnostic evaluation and medical management of nephrolithiasis in children. We summarized this literature and drew on studies performed in adult populations to augment areas in which no studies of sufficient quality have been performed in children, and to highlight areas in need of research.

RESULTS

During the last 25 years the incidence of nephrolithiasis in children has increased by approximately 6% to 10% annually and is now 50 per 100,000 adolescents. Kidney stones that form during childhood have a similar composition to those that form in adulthood. Approximately 75% to 80% of stones are composed of predominantly calcium oxalate, 5% to 10% are predominantly calcium phosphate, 10% to 20% are struvite and 5% are pure uric acid. The recurrence rate of nephrolithiasis in patients with stones that form during childhood is poorly defined. Ultrasound should be used as the initial imaging study to evaluate children with suspected nephrolithiasis, with noncontrast computerized tomography reserved for those in whom ultrasound is nondiagnostic and the suspicion of nephrolithiasis remains high. Current treatment strategies for children with kidney stone disease are based largely on extrapolation of studies performed in adult stone formers and single institution cohort or case series studies of children. Tamsulosin likely increases the spontaneous passage of ureteral stones in children. Increased water intake and reduction of salt consumption should be recommended for all children with a history of kidney stones. Potassium citrate is a potentially effective medication for children with calcium oxalate stones and concomitant hypocitraturia, as well as children with uric acid stones. However, long-term compliance with therapy and the effect on decreasing stone recurrence in children are unknown. Based largely on efficacy in adult populations, thiazide diuretics should be considered in the treatment of children with calcium based stones and persistent hypercalciuria refractory to reductions in salt intake.

CONCLUSIONS

The incidence of kidney stone disease in children is increasing, yet few randomized clinical trials or high quality observational studies have assessed whether dietary or pharmacological interventions decrease the recurrence of kidney stones in children. Collaborative efforts and randomized clinical trials are needed to determine the efficacy and effectiveness of alternative treatments for children with nephrolithiasis, particularly those with calcium oxalate stones and concomitant hypercalciuria and hypocitraturia. Additional areas in need of study are the optimal length of time for a trial of stone passage in children, the cost-effectiveness of medical expulsive therapy vs analgesics alone, and the size and location of stones for which medical expulsive therapy is most effective.

Ultrastructural and elemental analysis of sialoliths and their comparison with nephroliths

AIM

Sialoliths are common in the submandibular gland and its duct system, although their exact cause of formation is still a matter of debate. The aims of this study were to: (a) analyze sialoliths ultrastructurally, and to determine the role of foreign bodies or organic materials in the formation of sialolith nuclei; and (b) compare nephroliths with sialoliths ultrastructurally.

METHODS

Three sialoliths and two nephroliths were analyzed ultrastructurally by a scanning electron microscope and X-ray diffractometer.

RESULTS

The main structures of the sialoliths were found to be hydroxyapatite crystals. No organic cores were observed in the central parts of the sialoliths. In nephroliths, calcium oxalate, calcium phosphate, and struvite crystals were found. The energy-dispersive X-ray microanalysis found that sialoliths and nephroliths were predominantly composed of elements comprising calcium, phosphorous, magnesium, sodium, chloride, silicon, iron, and potassium.

CONCLUSION

Sialoliths in the submandibular salivary glands might form secondary to sialadenitis, but not via a luminal organic nidus.

[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.

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.

Recent finding and new technologies in nephrolitiasis: a review of the recent literature

This review summarizes recent literature on advances regarding renal and ureteral calculi, with particular focus in areas of recent advances in the overall field of urolithiasis. Clinical management in everyday practice requires a complete understanding of the issues regarding metabolic evaluation and subgrouping of stone-forming patients, diagnostic procedures, effective treatment regime in acute stone colic, medical expulsive therapy, and active stone removal. In this review we focus on new perspectives in managing nephrolitihiasis and discuss recentadvances, including medical expulsive therapy, new technologies, and refinements of classical therapy such as shock wave lithotripsy, give a fundamental modification of nephrolithiasis management. Overall, this field appears to be the most promising, capable of new developments in ureterorenoscopy and percutaneous approaches. Further improvements are expected from robotic-assisted procedures, such as flexible robotics in ureterorenoscopy.

Impact of Residual Fragments following Endourological Treatments in Renal Stones

Today, shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), and flexible ureterorenoscopy (URS) are the most widely used modalities for the management of renal stones. In earlier series, treatment success of renal calculi assessed with KUB radiography, ultrasound, or intravenous pyelography which are less sensitive than CT that leads to be diversity of study results in reporting outcome. Residual fragments (RFs) after interventional therapies may cause pain, infection, or obstruction. The size and location of RFs following SWL and PCNL are the major predictors for clinical significant symptoms and stone events requiring intervention. There is no consensus regarding schedule for followup of SWL, PCNL, and flexible URS. Active monitoring can be recommended when the stones become symptomatic, increase in size, or need intervention. RFs <4 mm after SWL and <2 mm after PCNL and flexible URS could be actively monitored on an annual basis with CT. Early repeat SWL and second-look endoscopy are recommended after primary SWL and PCNL, respectively. There is insufficient data for flexible URS, but RFs can be easily treated with repeat URS. Finally, medical therapy should be tailored based on the stone analysis and metabolic workup that may be helpful to prevent regrowth of the RFs.

Management of Clinically Insignificant Residual Fragments following Shock Wave Lithotripsy

Clinically insignificant residual fragments (CIRFs) are small fragments (less than 5 mm) that are present in upper urinary tract at the time of regular post-SWL followup. The term is controversial because they may remain silent and asymptomatic or become a risk factor for stone growth and recurrence, leading to symptomatic events, and need further urologic treatment. Although a stone-free state is the desired outcome of surgical treatment of urolithiasis, the authors believe that the presence of noninfected, nonobstructive, asymptomatic residual fragments can be managed metabolically in order to prevent stone growth and recurrence. Further urologic intervention is warranted if clinical indications for stone removal are present.

Longitudinal study of bone mineral density in children with idiopathic hypercalciuria

Children with idiopathic hypercalciuria (IH) may have a reduced bone mineral density (BMD), which could impact on bone health in adulthood. There is currently no strong evidence for a preferred treatment of such children. The aim of our study was to evaluate the BMD z-score before and after treating children and adolescents with IH with potassium citrate and thiazides. The study consisted of a historical cohort of 80 pediatric patients who were evaluated between October 1989 and November 2010. Bone scanning and densitometry measurements were made with dual-emission X-ray absorptiometry. Lumbar-spine BMD (g/cm(2)) and BMD z-score were evaluated before and after treatment. The t test and Mann-Whitney U test were used for statistical analysis. Forty-three boys and 37 girls were followed for a median time of 6.0 years. Median calcium excretion before and after treatment was 5.0 and 2.6 mg/kg/24 h, respectively. The BMD z-score changed significantly from -0.763 ± 0.954 (mean ± SD) to -0.537 ± 0.898 (p < 0.0001) before and after treatment, respectively. The BMD z-score of the patients improved with treatment, suggesting a beneficial effect and potential need for treatment. However, the lack of a control group points to the need for future studies to corroborate this outcome.

Nutritional aspect of nephrolithiasis

Nephrolithiasis is associated with a variety of abnormalities in urinary composition. These abnormal urinary risk factors are due to dietary indiscretions, physiological-metabolic disturbances or both. Stone disease is morbid and costly, and the recurrence rates may be as high as 30-50% after 5 years. Efforts to prevent stone formation are, therefore, essential. Dietary factors play an important role in kidney stone formation. Tailored dietary recommendations based on metabolic evaluation should be offered to patients for the prevention of recurrence of stone formation. Dietary intervention and subsequent evaluations of therapeutic efficacy should be based on results from multiple 24-h urine collections. Urine flow of >1 ml/kg/h almost eliminates the risk of supersaturation for calcium oxalate, calcium phosphate and uric acid, thus protecting from the formation of corresponding kidney stones. In patients with cystenuria, the required urine flow may even be higher and, in cases such as primary xanthinuria, high fluid intake is required. Milk intake in these patients should be within the RDA of calcium and protein. In children, recommendation of a high fluid intake has only limited success. Nevertheless, each patient should be advised about adequate fluid intake to increase urine volume in accordance with body size. Although children with hypocitraturia may benefit from therapeutic agents that raise the urine citrate concentration, all children bearing residual fragments should be counseled on adequate fluid intake along with potassium citrate treatment to prevent stone regrowth or formation.

Effects of repeated extracorporeal shock wave in urinary biochemical markers of rats

PURPOSE

To access the effect of repeated extracorporeal shock wave (ESW) on urinary biochemical markers

METHODS

20 rats were assigned for ESW (Direx Tripter X1(R) - 14 KV) to one of two groups: G1 (n=10) one ESW; G2 (n=10) two ESWs within a 14-day interval. Within the twenty-four hour period before and after the application of shock waves, the animals were placed in metabolic cages for 24 hour urine collection. The ph, creatinine, sodium, potassium, chlorides, calcium, magnesium, phosphorus, oxalates, alkaline phosphatase and citrates were measured. Twenty-four hours after the material was collected for urinary determination, the animals underwent nephrectomy of the kidney submitted to the ESW applications and were, then, sacrificed. The kidneys were processed for histopathological examination.

RESULTS

Small variations in the biochemical markers were found in both groups, with no significant differences between the values obtained either prior to or following the ESW applications, except for citrate and alkaline phosphatase. Citraturia decreased significantly in group 2, following the second ESWL application (24.8 +/- 3.0 mg/day after the first ESWL vs. 15.3 +/- 2.2 mg/day after the second ESWL; p < 0.05). Alkaline phosphatase increased significantly following ESWL in group I (0.57 +/- 0.02 vs. 0.79 +/- 0.04 micromol/mg creatinine; p < 0.01) and also in group 2 (0.69 +/- 0.05 vs. 0.83 +/- 0.03 micromol/mg creatinine; p < 0.05). Glomerular, interstitial and sub-capsular hemorrhage with perivascular edema was found in the animals in both groups studied.

CONCLUSIONS

A significant increase in urinary alkaline phosphatase was found in both groups studied, suggesting a proximal tubule lesion. In the group of rats undergoing more than one ESWL application, a smaller urinary citrate excretion was noticed, which may be a factor contributing for the formation of new calculi.

Pediatric urolithiasis: the current surgical management

Children represent about 1% of all patients with urolithiasis, but 100% of these children are considered high risk for recurrent stone formation, and it is crucial for them to receive a therapy that will render them stone free. In addition, a metabolic workup is necessary to ensure a tailored metaphylaxis to prevent or delay recurrence. The appropriate therapy depends on localization, size, and composition of the calculus, as well as on the anatomy of the urinary tract. In specialized centers, the whole range of extracorporeal shock-wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL) are available for children, with the same efficiency and safety as in adults.

Increased calcium and decreased magnesium and citrate concentrations of submandibular/sublingual saliva in sialolithiasis

OBJECTIVE

The purpose of the present study was to investigate the electrolyte alterations of submandibular/sublingual saliva in submandibular sialolithiasis patients compared with saliva from healthy controls.

DESIGN

Submandibular/sublingual saliva was collected from 10 submandibular sialolithiasis patients and from 10 sex- and age-matched healthy controls. Ion chromatography was performed to determine the concentrations of inorganic cations (potassium, calcium, magnesium, and sodium), inorganic anions (chloride, phosphate, nitrate, and sulphate) and organic anions (thiocyanate, lactate, acetate, and citrate).

RESULTS

The calcium concentration was significantly higher in sialolithiasis patients than in controls (P<0.05). In contrast, the levels of magnesium and citrate in the saliva of sialolithiasis patients were significantly reduced compared to the values obtained in controls (P<0.05). No significant differences were detected among other ions.

CONCLUSIONS

Our findings indicate that saliva electrolyte composition of sialolithiasis patients is substantially altered with respect to crystallisation mechanisms. Increased calcium ion as a crystallisation substance and decreased magnesium and citrate ions as crystallisation inhibitors may be involved in the etiopathology of calculi formation.

Urine calcium/citrate ratio in children with hypercalciuric stones

Hypercalciuria is a common cause for stone formation in children. The aim was to delineate the role of urinary citrate in hypercalciuric children for protection against calcium stone formation. We evaluated random urine calcium, citrate, and creatinine in 149 controls, 78 hypercalciuric nonstone formers, and 34 hypercalciuric children with stone. Urine citrate/creatinine was highest in hypercalciuric nonstone formers 899 +/- 351 compared with controls 711 +/- 328 and stone formers 595 +/- 289 (p < 0.01 vs. both). Calcium/creatinine ratio was similar in hypercalciuric stone and nonstone formers, but significantly higher than controls. Consequently, urine calcium/citrate ratio (mg/mg) increased from control 0.17 +/- 0.17 to 0.41 +/- 0.23 (p < 0.001) in hypercalciuric nonstone formers, and to 0.65 +/- 0.46 in stone formers (p < 0.001 compared with other groups). Area under receiver operating characteristic curve combined with multilevel risk analyses found calcium/citrate ratio of 0.326 to provide good discrimination between control and stone formers. We found 5th percentile for random urine citrate/creatinine ratio in school-aged children to be 176 mg/g, elevated urinary citrate excretion in hypercalciuric children to be protective against stone formation, and urine calcium/citrate ratio to be a good indicator for risk of stone formation. Whether intervention in hypercalciuric children to lower urine calcium/citrate <0.326 will provide protection against stone formation needs to be studied.

Tablets of the potassium citrate may cause a stone-like image: a case report

An 8-year-old girl with left proximal ureteral stone (4 mm) was referred to our hospital to treat with shock wave lithotripsy (SWL). Fifteen days after the first SWL session, a plain film of kidneys, ureters and bladder (KUB) demonstrated a new stone-like opacity (10 mm) on the left kidney location other than previous stone of 4 mm. We counseled with her parents and learned that she took a potassium citrate tablet 2 h before. Potassium citrate is a radio-opaque drug and may cause a stone-like image during the stone management. Urologists should consider this particularity of potassium citrate in patients using this drug to avoid unnecessary interventions. To our knowledge, this is the first case in the literature.

Diagnosis and management of hypercalciuria in children

PURPOSE OF REVIEW

In this review, recent advances in the epidemiology, genetics, clinical associations and management of idiopathic hypercalciuria will be discussed.

RECENT FINDINGS

A significant genetic contribution exists in the pathophysiology of hypercalciuria. Although several candidate genes and genetic alterations have been proposed, identification of precise gene(s) responsible remains elusive. Decreased bone density has been increasingly associated with hypercalciuria. Recent publications have suggested that bisphosphonates may play a role in the management in patients in whom both hypercalciuria and decreased bone density are present.

SUMMARY

Idiopathic hypercalciuria is a common disorder in children and can present with a range of clinical presentations such as hematuria, voiding dysfunction, flank pain, abdominal pain, nephrolithiasis, urinary tract infection and decreased bone mineral density. Dietary modifications are often sufficient in the management of hypercalciuria. If the symptoms persist or a rare monogenic disorder is present, consideration should be given to medical treatment with a thiazide diuretic and/or citrate therapy.

Adjuvant therapy after surgical stone management

The aim of this article was to review the most widely researched adjuvant medical therapies for the surgical management of urolithiasis. Articles were identified and reviewed from PubMed and Medline databases with MeSH headings focusing on the various surgical treatments of urolithiasis and adjuvant therapy. Additional articles were retrieved from references and conference proceedings. Surgical treatments reviewed included shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. Adjuvant therapy was considered medical or complementary therapy as an adjunct to these surgical interventions. Adjuvant therapy for the surgical management of urolithiasis has been documented to increase stone-free rates, reduce stone remission rates, prevent renal damage, and decrease postoperative morbidity. A variety of agents have been studied, ranging from antioxidants to alpha-blockers and to alkalinizing agents. Additionally, there is increasing interest in complementary adjuvant therapy (ie, acupuncture). Adjuvant therapy is a fertile area for research in the surgical management of urolithiasis. The optimal agents have yet to be determined and therefore further investigation is warranted and necessary.

Effect of verapamil on urinary stone-forming risk factors

Prevention of recurrent stone formation will only be possible with careful metabolic evaluation and appropriate management. In this present prospective study, a total of 95 patients with calcium oxalate (CaOx) stone disease were evaluated with respect to the effects of a calcium channel blocking agent (verapamil) therapy on stone-forming risk factors. A total of 95 patients with CaOx urolithiasis were well evaluated for the possible specific effects of verapamil administration on stone-forming risk factors during long-term follow-up. All patients had calcium-containing stones with normal renal morphology and function without any urinary tract infection. The follow-up period ranged from 12 to 36.6 months, with a mean value of 24.4 months. The age of the patients (54 male and 41 female; M/F: 1.31) ranged from 20 to 46 years (mean 34.3 years). On metabolic evaluation all patients had some kind of risk factors and patients were independently randomized into two groups, namely group 1 (n = 49): patients receiving calcium entry blocker, verapamil hydrochloride (isoptin 240 mg KKH tablets, oral t.i.d.); group 2 (n = 46): patients receiving no specific therapy (control patients) that were matched for sex and age. Follow-up results (at least 1 year) with respect to the changes in urinary stone-forming risk factors were recorded in both groups. During long-term follow-up patients undergoing no specific therapy did not show a significant change with respect to the urinary levels of stone-forming risk factors when compared with the others receiving verapamil on a regular basis. In the light of our results as well as the literature data, we believe that the pathophysiological mechanisms underlying the effect of verapamil on stone formation (as a result of enhanced crystal deposition) and on the excretion of the urinary stone-forming risk factors have to be well evaluated in further experimental as well as clinical studies. Although the exact mechanism of action is not clear; we may claim that the limitation of internal calcium shift by these agents may also well effect the tubular process related to oxalate handling which ultimately limits its excretion in urine.