Increasing Prevalence of Nephrolithiasis in Association with Increased Body Mass Index in Children: A Population Based Study

Risk factors for recurrence in pediatric urinary stone disease

BACKGROUND

Children's urinary system stones may develop from environmental, metabolic, anatomical, and other causes. Our objective is to determine the recurrence and prognosis, demographic, clinical, and etiological characteristics of children with urolithiasis.

METHODS

Medical records of patients were evaluated retrospectively. Patients' demographic data and medical history, serum/urine biochemical and metabolic analysis, blood gas analysis, stone analysis, imaging findings, and medical/surgical treatments were recorded.

RESULTS

The study included 364 patients (male 187). Median age at diagnosis was 2.83 (IQR 0.83-8.08) years. The most common complaints were urinary tract infection (23%) and urine discoloration (12%). Sixty-two percent had a family history of stone disease. At least one metabolic disorder was found in 120 (88%) of 137 patients having all metabolic analyses: hypercalciuria was found in 45%, hypocitraturia in 39%, and hyperoxaluria in 37%. Anatomical abnormalities were detected in 18% of patients. Of 58 stones analyzed, 65.5% were calcium and 20.6% were cystine stones. Stone recurrence rate was 15% (55/364). Older age (> 5 years), family history of stone disease, stone size (≥ 5 mm), and urinary system anatomical abnormalities were significantly associated with stone recurrence (p = 0.027, p = 0.031, p < 0.001, and p < 0.001, respectively). In adjusted logistic regression analysis, stone size ≥ 5 mm (OR 4.85, 95% CI 2.53-9.3), presence of urinary system anatomical abnormalities (OR 2.89, 95% CI 1.44-5.78), and family history of stone disease (OR 2.41, 95% CI 1.19-4.86) had increased recurrence rate.

CONCLUSIONS

All children with urolithiasis should be evaluated for factors affecting stone recurrence. Children at higher risk of recurrence need to be followed carefully.

Utilizing the Ex-Vivo Bovine Model in Retrograde Intrarenal Surgery Training

OBJECTIVES

To present an ex-vivo bovine model for retrograde intrarenal surgery (RIRS) training.

MATERIALS AND METHODS

The model was specifically developed for a pre-congress course organized as part of the National Pediatric Urology Congress. The course involved a two-day online theoretical segment followed by hands-on training. Bovine kidneys were chosen for their anatomical resemblance to human kidneys. The kidneys were sourced from a local slaughterhouse, ensuring the intactness of the pelvis, ureters, and perirenal fat. A Modified Larssen solution was used for tissue preservation. The tissue was positioned within a cardboard box, with specific preparation techniques to ensure realism. During the hands-on training, participants utilized a flexible ureterorenoscope for practice. After the course, participants completed an 18-question survey assessing the model and training experience.

RESULTS

24 participants completed the training and survey. Four out of eight procured kidneys were suitable. The model's cost was 18 euros. 87.5% of participants reported increased RIRS confidence. Those with prior course experience rated the model's anatomical resemblance higher (p=0.016). No significant difference was observed in feedback on the model's durability or tactile feedback based on prior experience (p>0.05).

CONCLUSION

The ex-vivo bovine model provides a promising alternative for RIRS training. While further studies are needed to validate its widespread application, initial feedback suggests it offers a balance between cost-effectiveness and realistic training experience.

The association of visceral adiposity index with the risk of kidney stone and kidney stone recurrence

AIM

Our aim in this study was primarily to assess the relationship between visceral adiposity index (VAI) and the risk of kidney stones and kidney stone recurrence in US adults.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) 2007-2014 for our analysis. VAI was calculated from waist circumference (WC), body mass index (BMI), triglycerides (TG), and high-density lipoprotein-cholesterol (HDL-C). Kidney stones and recurrence of kidney stones were obtained from questionnaire interview data. We used multivariate logistic regression analysis to explore the correlation between VAI and the risk of kidney stone and kidney stone recurrence. In addition, we performed subgroup analysis, interaction tests, and restricted cubic spline (RCS) analysis.

RESULTS

A total of 9886 participants were included in this study, with a prevalence of 9.24% for kidney stones and 2.97% for recurrence of kidney stones. The prevalence of kidney stones and kidney stone recurrence increased with higher quartiles of VAI. We observed a significantly positive correlation between VAI and the risk of kidney stone and kidney stone recurrence. Participants with the highest VAI quartiles had a 48% (OR: 1.48, 95%CI: 1.08-2.02) and 52% (OR: 1.52, 95%CI: 0.86-2.71) increased risk of kidney stones and kidney stone recurrence, respectively, compared to participants with the lowest VAI quartiles. Subgroup analysis and interaction tests demonstrated this positive association independent of different subgroup factors.

CONCLUSION

Visceral fat accumulation may be associated with an increased risk of kidney stones and kidney stone recurrence.

Mini-versus standard percutaneous nephrolithotomy in pediatric population: A randomized controlled trial

INTRODUCTION

Mini PCNL has gained popularity in adult patients due to reduction in the complication rate with comparable stone free rate. There is paucity of level 1 evidence regarding the benefit of mini PCNL in the pediatric group.

OBJECTIVE

We performed a randomised study to compare mini PCNL (mPCNL) with standard PCNL (sPCNL) for the management of renal calculi in patients less than 18 years of age in terms of safety, efficacy, and stone-free rate (SFR).

MATERIALS AND METHODS

A randomised controlled trial was performed on 50 children who underwent PCNL from June 2015 to March 2021, who were divided into two groups. Group I had 25 patients managed with mPCNL (sheath size 16.5 Fr) and Group II had 25 patients who underwent sPCNL (sheath size 26 Fr). Primary outcomes including stone free rates (SFR) and hemoglobin drop and secondary outcomes like operative time, complications, pain score, need of analgesia, incidence of nephrostomy site leak, hospital stay in days were compared between the two groups.

RESULTS

The mean age of patients in groups I and II was 9.4 ± 2.6 and 10.4 ± 2.26 years, respectively (p = 0.15). The mean stone sizes in both groups I and II were 18.6 ± 2.56 and 20.2 ± 3.58 mm, respectively (p > 0.05). The stone free rate for group I was 88% and for group II, 92% (p = 0.64). The average drop in hemoglobin was higher in group II compared to group I (1.1 ± 0.31 g/dl and 1.7 ± 0.23 g/dl respectively; p < 0.0001), however the mean blood transfusion rate was not significantly different in both groups. The operating time was shorter in group II compared to group I (p-value - 0.0030). The pain scores were lesser for the group I. Grade I complications were higher in group II as compared to group I (p-0.047); however, grade II complications were comparable in both groups. The mean hospital stay was not significantly different in both groups.

DISCUSSION

This study confirms the role of mini PCNL in pediatric patients with renal stones. The stone clearance rate of mini PCNL is equivalent to standard PCNL, with lesser blood loss and postoperative complications, however with longer operative time during mPCNL. The small number of the participants in both arms is a limitation of this study and may also reflect fewer children with urolithiasis being treated surgically even in a tertiary care referral centre.

CONCLUSIONS

Mini-PCNL offers equivalent stone free outcome with lower complications rate compared to the standard PCNL for all types of renal stones.

A population-based retrospective cohort study of surgical trends and outcomes of pediatric urolithiasis in Ontario, Canada (2002-2019)

INTRODUCTION

The worldwide incidence of pediatric urinary stone disease (PUSD) is increasing. However, there is no commensurate data on whether this translates to an increasing need for surgical intervention for PUSD, given the role of conservative management.

OBJECTIVE

We aimed to evaluate the trends and outcomes of clinically significant PUSD, using administrative databases to identify patients surgically treated for PUSD.

STUDY DESIGN

This retrospective population-based cohort study assessed the incidence and trends of surgically treated PUSD and outcomes in Ontario, Canada in patients <18 years of age who underwent their first PUSD procedure between 2002 and 2019 utilizing administrative databases held at the Institute of Clinical Evaluative Sciences (ICES). We assessed the incidence of surgically treated PUSD, demographics, initial surgical treatment and imaging modality, and risk factors for repeat intervention within 5 years. Statistical analyses summarized demographics, surgical trends, and logistic regression was used to identify risk factors for repeat surgical intervention.

RESULTS

We identified 1149 patients (mean age 11.3 years), with 59.6% older than 12 years. There was a decrease in the number of PUSD procedures performed per year that was close to statistical significance (p = 0.059) and a trend towards increased utilization of ureteroscopy (URS) compared with Shockwave Lithotripsy (SWL). In addition, there was a significant increase in the proportion of females surgically treated with PUSD (p = 0.001). In the 706 patients followed for 5 years, 17.7% underwent a repeat procedure within 6 months, while 20.4% underwent a repeat procedure from 6-months to 5 years. Renal stone location (OR 2.79, 95% confidence interval (CI) 1.62-4.80, p = 0.0002) and index SWL (OR 1.66, 95% CI 1.20-2.31, p = 0.0025) were risk factors for repeat surgical intervention within the first 6-months. There was an increasing utilization of ultrasound (US) compared to computerized tomography (CT) (p = 0.0008).

DISCUSSION

Despite the literature reporting increasing PUSD incidence, we observed a non-significant decrease in the number of surgical PUSD procedures performed. Exclusion of those treated conservatively may explain our results. The increase in the proportion of females treated reflects the narrowing gender gap in stone disease. A trend towards increased URS utilization was observed and re-intervention rates were similar to previous studies.

CONCLUSION

The overall rate of surgically treated PUSD did not show an increasing trend in Ontario, Canada from 2002 to 2019. URS was the most common surgical treatment modality, with a corresponding decline in SWL rates. PUSD was associated with a high surgical re-intervention rate within 6 months.

Pediatric Nephrolithiasis

The prevalence of pediatric nephrolithiasis has increased dramatically in the past two decades for reasons that have yet to be fully elucidated. Workup of pediatric kidney stones should include metabolic assessment to identify and address any risk factors predisposing patients to recurrent stone formation, and treatment should aim to facilitate stone clearance while minimizing complications, radiation and anesthetic exposure, and other risks. Treatment methods include observation and supportive therapy, medical expulsive therapy, and surgical intervention, with choice of treatment method determined by clinicians' assessments of stone size, location, anatomic factors, comorbidities, other risk factors, and preferences and goals of patients and their families. Much of the current research into nephrolithiasis is restricted to adult populations, and more data are needed to better understand many aspects of the epidemiology and treatment of pediatric kidney stones.

Complication rate after pediatric shock wave lithotripsy according to Clavien-Dindo grading system: results from a systematic review and meta-analysis of the existing literature

PURPOSE

Shockwave lithotripsy (SWL) is a minimally invasive technique utilized for renal and ureteric stones in children. Despite being considered safe, certain complications have been recorded. We performed this systematic review and meta-analysis to provide a pooled analysis of Clavien-Dindo graded complications after SWL in children.

METHODS

MEDLINE/PubMed, Scopus and Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, were screened from inception to 12/02/2022 by two authors independently. Only randomized controlled trials providing Clavien-Dindo classification or relevant clinical information were considered eligible. Overall complications were calculated using the aggregate number of each complication divided by the total number of patients in studies with data.

RESULTS

Pooled analysis revealed that from children treated with SWL, 27.7% [95% CI 13.1-49.4] suffered Clavien I complications, 4.9% [95% CI 3.1-7.6] Clavien II complications, 2.7% [95% CI 1.6-4.7] Clavien III complications, 2.3% [95% CI 1.3-4] Clavien IV complications, while no Clavien V complications were recorded. In total, 28.1% [95% CI 15.6-45.3] of children suffered minor complications (Clavien-Dindo I-II), while 3% [95% CI 1.8-5] major complications (Clavien-Dindo III-V). Pooled analysis revealed that 10.7% [95% CI 3.2-30.1] of patients suffered macroscopic hematuria, 7.3% [95% CI 2.1-22.7] pain, 5.5% [95% CI 3.3-9] steinstrasse, 5.3% [95% CI 3-9.3] fever, 2.2% [95% CI 0.8-5.6] sepsis, 1.1% [95% CI 0.3-3.7] urinoma, 1% [95% CI 0.4-2.7] symptomatic hematoma and 1% [95% CI 0.3-2.7] asymptomatic hematoma. Need for re-treatment was 42.6% [95% CI 31.4-54.7] and need for auxiliary procedures was 11.8% [95% CI 8.5-16.1].

CONCLUSION

SWL is an irreplaceable tool for treating urolithiasis in children. Although a minimally invasive technique, parents and children should be adequately informed about the risk of minor/major complications.

Complication rate after pediatric shock wave lithotripsy according to Clavien-Dindo grading system: results from a systematic review and meta-analysis of the existing literature

PURPOSE

Shockwave lithotripsy (SWL) is a minimally invasive technique utilized for renal and ureteric stones in children. Despite being considered safe, certain complications have been recorded. We performed this systematic review and meta-analysis to provide a pooled analysis of Clavien-Dindo graded complications after SWL in children.

METHODS

MEDLINE/PubMed, Scopus and Cochrane Central Register of Controlled Trials and Cochrane Database of Systematic Reviews, were screened from inception to 12/02/2022 by two authors independently. Only randomized controlled trials providing Clavien-Dindo classification or relevant clinical information were considered eligible. Overall complications were calculated using the aggregate number of each complication divided by the total number of patients in studies with data.

RESULTS

Pooled analysis revealed that from children treated with SWL, 27.7% [95% CI 13.1-49.4] suffered Clavien I complications, 4.9% [95% CI 3.1-7.6] Clavien II complications, 2.7% [95% CI 1.6-4.7] Clavien III complications, 2.3% [95% CI 1.3-4] Clavien IV complications, while no Clavien V complications were recorded. In total, 28.1% [95% CI 15.6-45.3] of children suffered minor complications (Clavien-Dindo I-II), while 3% [95% CI 1.8-5] major complications (Clavien-Dindo III-V). Pooled analysis revealed that 10.7% [95% CI 3.2-30.1] of patients suffered macroscopic hematuria, 7.3% [95% CI 2.1-22.7] pain, 5.5% [95% CI 3.3-9] steinstrasse, 5.3% [95% CI 3-9.3] fever, 2.2% [95% CI 0.8-5.6] sepsis, 1.1% [95% CI 0.3-3.7] urinoma, 1% [95% CI 0.4-2.7] symptomatic hematoma and 1% [95% CI 0.3-2.7] asymptomatic hematoma. Need for re-treatment was 42.6% [95% CI 31.4-54.7] and need for auxiliary procedures was 11.8% [95% CI 8.5-16.1].

CONCLUSION

SWL is an irreplaceable tool for treating urolithiasis in children. Although a minimally invasive technique, parents and children should be adequately informed about the risk of minor/major complications.

Use of whole-exome sequencing to identify novel monogenic gene mutations and genotype-phenotype correlations in Chinese Han children with urolithiasis

The incidence of urolithiasis (UL) in children has been increasing. Although the pathogenesis of pediatric UL is controversial and remains unclear, multiple monogenic causes of UL have been identified. We aim to investigate the prevalence of inherited UL causes and explore the genotype-phenotype correlation in a Chinese pediatric group. In this study, we analyzed the DNA of 82 pediatric UL patients using exome sequencing (ES). The data of metabolic evaluation and genomic sequencing were subsequently analyzed together. We detected 54 genetic mutations in 12 of 30 UL-related genes. A total of 15 detected variants were described as pathogenic mutations, and 12 mutations were considered likely pathogenic. Molecular diagnoses were made in 21 patients with pathogenic or likely pathogenic variants. Six novel mutations that were not previously reported were identified in this cohort. Calcium oxalate stones were detected in 88.9% cases (8/9) with hyperoxaluria-related mutations, while 80% of individuals (4/5) with cystinuria-causing defects were diagnosed with cystine stones. Our study highlights the significant genetic abnormalities in pediatric UL and demonstrates the diagnostic power of ES for screening patients with UL.

Obesity Is Positively Associated and Alcohol Intake Is Negatively Associated with Nephrolithiasis

The current research investigated the impacts of smoking, alcohol consumption, and obesity on the development of nephrolithiasis. We included ≥40-year-old Koreans from the Korean National Health Insurance Service-Health Screening Cohort. A total of 28,395 nephrolithiasis patients were compared with 113,580 control participants. Previous histories of smoking, alcohol consumption, and obesity were examined before the presence of nephrolithiasis. Conditional logistic regression analysis was performed to estimate the odds ratios (ORs) of smoking, alcohol consumption, and obesity for nephrolithiasis. Further analyses were conducted, according to age, sex, smoking, alcohol consumption, and obesity. The current smoking status was not linked with the presence of nephrolithiasis. Alcohol consumption was linked with a lower likelihood of the presence of nephrolithiasis (adjusted OR (aOR) = 0.89, 95% confidence intervals (CI) = 0.86−0.92, p < 0.001). Being obese was associated with a greater likelihood of the presence of nephrolithiasis ((95% CI) = 1.27 (1.22−1.31) < 1.42 (1.37−1.46) < 1.59 (1.47−1.71) for overweight < obese I < obese II). The relation of alcohol consumption and obesity with nephrolithiasis was consistent in the subgroups. The presence of nephrolithiasis was positively linked with obesity and negatively linked with alcohol consumption.

Association between Temperature and Inpatient Stone Admission in a Pediatric Population

BACKGROUND

Higher temperatures have been associated with increased stone formation and subsequent utilization of hospital resources, including inpatient admission. However, these observations have been derived from the adult population. We sought to examine if this purported association extends to the pediatric population.

METHODS

We used the 2016 Kids' Inpatient Database to identify nationwide pediatric inpatient admissions related to nephrolithiasis. Temperature data from the National Oceanic and Atmospheric Administration was linked to each admission. Comparative statistics analyzed patient and admission characteristics. Multivariable logistic regression analyzed associations between stone-related admissions and temperature. As a frame of reference, this analysis was replicated using the National Inpatient Sample from 2016 to evaluate associations in the adult population.

RESULTS

Of the 2,496,257 pediatric admissions, 8,453 (0.33%) were related to nephrolithiasis. Temperatures at the time of stone admission were higher than those during non-stone admission (55.9°F vs. 54.8°F, P<0.001). The stone admission group had a higher proportion of females than the non-stone admission group (64.8% vs. 55.4%, P<0.001). Stone admission was significantly associated with temperature (OR 1.025 per 10°F, 95% CI 1.003-1.049, P=0.03) and female sex (OR 1.097, 95% CI 1.027-1.171, P=0.006). In the adult population, 380,520 out of 30,000,941 patients (1.3%) were admitted with a stone. The effect of temperature on stone admissions was similar to that in the pediatric population (OR 1.020, 95% CI 1.014-1.026, P<0.001), but women were over 20% less likely to be admitted for stones than men (OR 0.770, 95% CI 0.757-0.784, P<0.001).

CONCLUSIONS

Increased temperatures were associated with an increased risk of stone-related admission in both the pediatric and adult populations. Females were at increased risk for stone-related admissions during childhood, but this trend reverses in adulthood.

Gender Differences in Kidney Stone Disease (KSD): Findings from a Systematic Review

Purpose of Review

The prevalence of kidney stones is rising and historically carries a preponderance for males. However, recent evidence has questioned whether this gender gap is closing. The aim of this systematic review was to examine this further as well as evaluate possible underlying causes.

Recent Findings

Recent evidence confirms the disparity in kidney stone disease between genders is closing. In the modern era, the rise in prevalence among females has been greater, especially in adolescence. Quality of life is also more adversely affected by kidney stone events among females who are also more likely to develop sepsis after endourological surgery. Males, however, are more likely to present with stone events during periods of high ambient temperatures

Summary

Recent literature demonstrates a temporal change in the disease burden of KSD among men and women. The latter, especially adolescent females, are more likely to develop KSD in their lifetime compared to previous eras. Determining causation is complex and continued research is warranted.

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.

Influence of Body Mass Index on the Surgical Outcomes of Flexible Ureteroscopy for Pediatric Upper Urinary Tract Aalculi-A Single Surgeon Experience

OBJECTIVE

To examine the association between body mass index (BMI) and surgical outcomes of flexible ureteroscopy (FURS) for pediatric upper urinary tract calculi and to estimate the influence of BMI percentile on the learning curve of pediatric FURS.

MATERIALS AND METHODS

We reviewed our prospectively maintained database containing children who had kidney or ureteral stones from June 2014 to April 2019. We calculated BMI and plotted it on the Centers for Disease Control and Prevention growth chart for sex and age to estimate BMI percentile. Patient demographics, intraoperative data, stone characteristics, stone-free rate (SFR), and complication rate (CR) were analyzed. Learning curves stratified by BMI percentile groups were generated.

RESULTS

The final analysis included 161 children, of whom 63 (39.1%) had upper body weight percentile (UBW), 64 (39.8%) had normal body weight percentile (NBW), and 34 (21.1%) had lower body weight percentile (LBW). The median stone burden of the 3 groups were 1.14 (IQR 0.50-3.41), 1.13 (IQR 0.70-3.14), and 0.95 (IQR 0.50-1.77), respectively (P = .17). The SFRs were 90.5% (57/63) in the UBW group, 81.2% (52/64) in the NBW group and 70.6% (24/34) in the LBW group (P = .04). The CRs were 15.9% (10/63), 21.9% (14/64), and 29.4% (10/34), respectively (P = .29). The learning curves showed that the SFR of FURS could be improved after about 100 cases. And decreasing BMI could steepen the learning curve of SFR.

CONCLUSIONS

BMI is associated with the SFR of FURS. LBW children had the lowest SFR compared to UBW and NBW children. Lower BMI percentile makes the success of FURS more challenging.

Imaging modalities and treatment of paediatric upper tract urolithiasis: A systematic review and update on behalf of the EAU urolithiasis guidelines panel

BACKGROUND

Prompt diagnosis and treatment of paediatric urolithiasis are required to avoid long term sequelae of renal damage.

OBJECTIVE

To systematically review the literature regarding the diagnostic imaging modalities and treatment approaches for paediatric urolithiasis.

STUDY DESIGN

PubMed, Science Direct, Scopus and Web of Science were systematically searched from January 1980-January 2019. 76 full-text articles were included.

RESULTS

Ultrasound and Kidney-Ureter-Bladder radiography are the baseline diagnostic examinations. Non-contrast Computed Tomography (CT) is the second line choice with high sensitivity (97-100%) and specificity (96-100%). Magnetic Resonance Urography accounts only for 2% of pediatric stone imaging studies. Expectant management for single, asymptomatic lower pole renal stones is an acceptable initial approach, especially in patients with non-struvite, non-cystine stones<7 mm. Limited studies exist on medical expulsive therapy as off-label treatment. Extracorporeal shock wave lithotripsy (SWL) is the first-line treatment with overall stone free rates (SFRs) of 70-90%, retreatment rates 4-50% and complication rates up to 15%. Semi-rigid ureteroscopy is effective with SFRs of 81-98%, re-treatment rates of 6.3-10% and complication rates of 1.9-23%. Flexible ureteroscopy has shown SFRs of 76-100%, retreatment rates of 0-19% and complication rates of 0-28%. SFRs after first and second-look percutaneous nephrolithotomy (PNL) are 70.1-97.3% and 84.6-97.5%, respectively with an overall complication rate of 20%. Open surgery is seldom used, while laparoscopy is effective for stones refractory to SWL and PNL. Limited data exist for robot-assisted management.

CONCLUSIONS

In the initial assessment of paediatric urolithiasis, US is recommended as first imaging modality, while non-contrast CT is the second option. SWL is recommended as first line treatment for renal stones <20 mm and for ureteral stones<10 mm. Ureteroscopy is a feasible alternative both for ureteral stones not amenable to SWL as well as for renal stones <20 mm (using flexible). PNL is recommended for renal stones >20 mm.

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.

Increased risk of new persistent opioid use in pediatric and young adult patients with kidney stones

INTRODUCTION

Adolescents and young adults are a vulnerable patient population for development of substance use disorder. However, the long-term impact of opioid prescribing in young adult patients with renal colic is not known. Our objective was to describe rates of opioid prescription and identify risk factors for persistent opioid use in patients age 25 years or younger with renal colic from kidney stones.

METHODS

Using previously validated, linked administrative databases, we performed a population-based, retrospective cohort study of opioid-naive patients age 25 years or younger with renal colic between July 1, 2013 and September 30, 2017 in Ontario. All family practitioner, urgent care, and specialist visits in the province were captured. Our primary outcome was persistent opioid use, defined as filling a prescription for an opioid between 91 and 180 days after initial visit. Ontario uses a narcotic monitoring system, which captures all opioids dispensed in the province.

RESULTS

Of the 6962 patients identified, 56% were prescribed an opioid at presentation and 34% of those were dispensed more than 200 oral morphine equivalents. There was persistent opioid use in 313 (8.1%) patients who filled an initial opioid prescription. In adjusted analysis, those prescribed an opioid initially had a significantly higher risk of persistent opioid use (odds ratio [OR] 1.85; 95% confidence interval [CI] 1.50-2.29) and opioid overdose (OR 3.45; 1.08-11.04). There was a dose-dependent increase in risk of persistent opioid use with escalating initial opioid dose. History of mental illness (OR 1.32; 1.02-1.71) and need for surgery (OR 1.71; 1.24-2.34) were also associated with persistent opioid use.

CONCLUSIONS

Among patients with kidney stones age 25 years or younger, filling an opioid prescription after presentation is associated with an increased risk of persistent opioid use 3-6 months later and a higher risk of serious long-term complications, such as opioid overdose.

Urologic treatment of nephrolithiasis

PURPOSE OF REVIEW

The purpose of this review is to describe the options and recent developments in the urologic treatment of nephrolithiasis in children. The prevalence of nephrolithiasis in children has increased over time. The urologic treatment of nephrolithiasis ranges from observation to medical expulsive therapy with an alpha blocker for a stone in a ureter to a variety of procedures for stone removal.

RECENT FINDINGS

Observation for small, asymptomatic renal stones is a reasonable strategy in children. Medical expulsive therapy with an alpha blocker may have a beneficial effect for passage of ureteral stones in children. Extracorporeal shock wave lithotripsy (ESWL) remains an important treatment for nephrolithiasis in children. Advances in ureteroscopy with clearer digital imaging and single use ureteroscopes have made ureteroscopy more attractive. Percutaneous nephrolithotomy is a more invasive treatment modality but remains a good choice for children with large-stone burdens and instruments are getting smaller. Open or laparoscopic stone surgery should be reserved for unique cases.

SUMMARY

Nephrolithiasis is increasing in children with differing urologic management options depending on the clinical scenario. A shared decision-making process with discussion of risks and benefits should be used to help patients and families choose a treatment option.

Evaluation of a child with suspected nephrolithiasis

PURPOSE OF REVIEW

As the incidence of nephrolithiasis in children doubles every 10 years it is becoming a common disease associated with significant morbidity along with considerable economic burden worldwide. The aim of this review is to summarize current data on the epidemiology and causes of renal stones in children and to provide a frame for the first clinical evaluation of a child with suspected nephrolithiasis.

RECENT FINDINGS

Dietary and environmental factors are the driving force of changing epidemiology. Diagnosis should be based on medical history, presenting signs, examination, first laboratory and radiological workup. Ultrasound should be the initial diagnostic imaging performed in pediatric patients while low-dose computed tomography is rarely necessary for management. Metabolic factors including hypercalciuria, hypocitraturia, low fluid intake as well as specific genetic diseases should be explored after the resolution of initial signs and symptoms.

SUMMARY

Appropriate initial evaluation, imaging technique, identification of risk factors and other abnormalities are essential for early diagnosis and prevention of stone-related morbidity in children with suspected nephrolithiasis.

Drug-Induced Urolithiasis in Pediatric Patients

Drug-induced nephrolithiasis is a rare condition in children. The involved drugs may be divided into two different categories according to the mechanism involved in calculi formation. The first one includes poorly soluble drugs that favor the crystallization and calculi formation. The second category includes drugs that enhance calculi formation through their metabolic effects. The diagnosis of these specific calculi depends on a detailed medical history, associated comorbidities and the patient's history of drug consumption. There are several risk factors associated with drug-induced stones, such as high dose of consumed drugs and long duration of treatment. Moreover, there are some specific risk factors, including urinary pH and the amount of fluid consumed by children. There are limited data regarding pediatric lithogenic drugs, and hence, our aim was to perform a comprehensive review of the literature to summarize these drugs and identify the possible mechanisms involved in calculi formation and discuss the management and preventive measures for these calculi.

Pediatric calculi: cause, prevention and medical management

PURPOSE OF REVIEW

The incidence of pediatric nephrolithiasis is on the rise, with a significant related morbidity and a concomitant relevant increase in healthcare costs. The purpose of this review is to portray the current epidemiology and cause of renal stones in children, to provide a framework for appropriate clinical evaluation on an individual basis, and a guidance regarding treatment and prevention for the significant risk of lifelong recurrence and deriving complications.

RECENT FINDINGS

The early identification of modifiable risk factors and other abnormalities is essential, to prevent related morbidity, the onset of chronic kidney disease, and the associated increased risk of developing other diseases. The implementation of risk reduction strategies, including dietary modifications and targeted pharmacological therapies, will significantly influence stone recurrences and preserve renal function.

SUMMARY

Future research is desirable, with the aim to strengthen personalized conservative management of pediatric nephrolithiasis as first-line treatment.

Increased body fatness adversely relates to 24-hour urine pH during childhood and adolescence: evidence of an adipo-renal axis

BACKGROUND

Reduced net acid excretion (NAE) capacity indicates a decrease in renal function. This reduction manifests as a disproportionally low 24-h urine pH in relation to the sum of actually excreted ammonium and titratable acidity by the kidney.

OBJECTIVE

The aim of this study was to test the hypothesis that higher body fatness is one determinant of kidney function impairment with a lowered urine pH even at a young age.

METHODS

NAE, pH, urea, and creatinine were measured in 24-h urine samples from 524 healthy children and adolescents (aged 6-17 y) participating in the DOrtmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study. Body fatness was assessed anthropometrically by body mass index-standard deviation score (BMI-SDS), fat mass index (FMI), body fat % (BF%), and waist circumference (WC). Multivariable linear and mixed linear regressions were used to examine cross-sectionally (n = 524 urine samples; age groups: 6-8, 9-11, 12-14, 15-17 y) and longitudinally (n = 1999 urine samples) the associations of body fatness with 24-h urine pH as the outcome variable, respectively.

RESULTS

After adjusting for the kidneys' total net acid load (24-h urinary NAE) and further relevant covariates, FMI showed significant inverse relations with urinary pH in all 4 age groups, and BMI-SDS, BF%, and WC each in 3 out of these 4 groups (P ≤ 0.02). Longitudinal results substantiated these interindividual relations and further showed intraindividual increases in body fatness to be paralleled by urine pH decreases (P ≤ 0.0002).

CONCLUSIONS

Independent of underlying acid load, an early increase in body fatness is associated with increased free proton excretion, and thus with a decline in the kidney's acid excretion function, which could potentiate the risk of renal nephrolithiasis.

Renal lithiasis and inflammatory bowel diseases, an update on pediatric population

BACKGROUND AND AIM OF THE WORK

Historical studies have demonstrated that the prevalence of symptomatic nephrolithiasis is higher in patients with inflammatory bowel disease (IBD), compared to general population. The aim of the review was to analyze literature data in order to identify the main risk conditions described in literature and the proposed treatment.

METHODS

A research on the databases PubMed, Medline, Embase and Google Scholar was performed by using the keywords "renal calculi/lithiasis/stones" and "inflammatory bowel diseases". A research on textbooks of reference for Pediatric Nephrology was also performed, with focus on secondary forms of nephrolithiasis.

RESULTS

Historical studies have demonstrated that the prevalence of symptomatic nephrolithiasis is higher in patients with inflammatory bowel disease (IBD), compared to general population, typically in patients who underwent extensive small bowel resection or in those with persistent severe small bowel inflammation. In IBD, kidney stones may arise from chronic inflammation, changes in intestinal absorption due to inflammation, surgery or intestinal malabsorption. Kidney stones are more closely associated with Crohn's Disease (CD) than Ulcerative Colitis (UC) in adult patients for multiple reasons: mainly for malabsorption, but in UC intestinal resection may be an additional risk. Nephrolithiasis is often under-diagnosed and might be a rare but noticeable extra-intestinal presentation of pediatric IBD. Secondary enteric hyperoxaluria the main risk factor of UL in IBD, this has been mainly studied in CD, whether in UC has not been completely explained. In the long course of CD recurrent urolithiasis and calcium-oxalate deposition may cause severe chronic interstitial nephritis and, as a consequence, chronic kidney disease. ESRD and systemic oxalosis often develop early, especially in those patients with multiple bowel resections. Even if we consider that many additional factors are present in IBD as hypomagnesuria, acidosis, hypocitraturia, and others, the secondary hyperoxaluria seems to finally have a central role. Some medications as parenteral vitamin D, long-term and high dose steroid treatment, sulfasalazine are reported as additional risk factors. Hydration status may also play an important role in this process. Intestinal surgery is a widely described independent risk factor. Patients with ileostomy post bowel resection may have relative dehydration from liquid stool, which, added to the acidic pH from bicarbonate loss, is responsible for this process. In this acidic pH, the urinary citrate level excretion reduces. The stones most commonly seen in these patients contain uric acid or are mixed. In addition, the risk of calcium containing stones also increases with ileostomy. The treatment of UL in IBD involves correction of the basic gastrointestinal tract inflammation, restricted dietary oxalate intake, and, at times, increased calcium intake. Citrate therapy that increases both urine pH and urinary citrate could also provide an additional therapeutic benefit. Finally, patients with IBD in a pediatric study had less urologic intervention for their calculosis compared with pediatric patients without IBD.

Confounding risk factors and preventative measures driving nephrolithiasis global makeup

Nephrolithiasis is increasing in developed and developing countries at an alarming rate. With the global spike in kidney stone diseases, it is crucial to determine what risk factors are influencing the current global landscape for kidney stones. Our aims for this review are: to identity and analyze the four categories of risk factors in contributing to the global scale of stone formation: lifestyle, genetics, diet, and environment; and discuss preventative measures for kidney stone formation. We also performed data search through the published scientific literature, i.e., PubMed^® and found that there is a significant link between lifestyle and obesity with cases of calcium stones. Food and Agriculture Organization of the United Nations and World Health Organization factor indicators for dietary intake and obesity, along with climate data were used to create the projected total risk world map model for nephrolithiasis risk. Complete global analyses of nephrolithiasis deplete of generalizations is nearly insurmountable due to limited sources of medical and demographic information, but we hope this review can provide further elucidation into confounding risk factors and preventative measures for global nephrolithiasis analysis.