Comparison of Risk Factors for Pediatric Kidney Stone Formation: The Effects of Sex

Management of Pediatric Urolithiasis in an Italian Tertiary Referral Center: A Retrospective Analysis

Background and Objectives: In recent years, the prevalence of pediatric urolithiasis has increased in North America and Western countries, though it is endemic in developing countries. The aim of this study is to describe the experience of a tertiary pediatric referral center in the surgical management of pediatric urolithiasis. Materials and Methods: We retrospectively reviewed the experience of patients ≤ 16 years old affected by urinary stones who underwent surgery. Results: From April 2021 to September 2023, 31 pediatric patients underwent surgical procedures for stone diseases at our department: 13 preschool-aged (1-5 years) and 18 school-aged (6-16 years) children. During this period, 12 URSs, 17 RIRSs, and 2 PCNLs were recorded. Five patients had residual fragments at first, so three of them underwent a second endourological lithotripsy (2 RIRSs and 1 URS). Complete clearance was finally achieved in 27 patients. The stone composition was evaluated in 25 cases. Conclusions: Numerous innovations in the surgical treatment of pediatric urolithiasis have resulted from the development of smaller devices and new technology. Our results show how, in experienced centers, retrograde and percutaneous lithotripsy are safe and effective procedures for use in pediatric populations.

Calculus anuria: a urological emergency with an excellent outcome

Calculus anuria is a catastrophic condition with dire consequences if not treated promptly. The purpose of this study was to identify factors which influence the short-term outcome of patients with calculus anuria. A retrospective analysis was conducted from January 2016 to December 2021, in children up to the age of 18 years, who presented with calculus anuria and required emergency decompression at Sindh Institute of Urology and Transplantation, Pakistan. One hundred and twenty-five children were included. Majority were born to consanguineous parents and a few of them had positive family history of stone disease. Severe illness was found in 25 (20%) patients and among them 8 (32%) required hemodialysis. Decompression by double J stenting is the preferred intervention in our institute and was done in 106 (85%) children, followed by percutaneous nephrostomy tube in 10 (8%) successfully. A small number of patients, 9 (7%) required both procedures to relieve their obstruction. A significant number of patients, about 115 (92%), attained normal renal functions after intervention. No pertinent factors were identified, relating to incomplete renal recovery in nine (7%) of the patients who unfortunately progressed to chronic kidney disease.

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.

Comparison of infants and children with urolithiasis: a large case series

We evaluated the demographic features, etiologic risk factors, treatment strategies, and outcome of the infants and children with urolithiasis (UL). A retrospective multicenter study was conducted including 23 Pediatric Nephrology centers in Turkey. The medical records of 2513 children with UL were reviewed. One thousand, three hundred and four boys and 1209 girls (1.1:1) were reported. The mean age at diagnosis was 39.5 ± 35 months (0.4-231 months), and 1262 patients (50.2%) were in the first year of life (infants). Most of the cases with infantile UL were diagnosed incidentally. Microlithiasis (< 3 mm) was found in 794 patients (31.6%), and 64.5% of the patients with microlithiasis were infants. Stones were located in the pelvis-calyces in 63.2% (n: 1530) of the cases. The most common stone type was calcium oxalate (64.6%). Hypocitraturia was the most common metabolic risk factor (MRF) in children older than 12 months, but in infancy, hypercalciuria was more common. Fifty-five percent of the patients had received at least one medical treatment, mostly potassium citrate. At the end of a year's follow-up, most of the patients with microlithiasis (85%) showed spontaneous remission. The rate of spontaneous stone resolution in infants was higher than in children. Spontaneous remission rate was higher in cases with MRF ( - ) stones than in MRF ( +) stones. However, remission rate with medical treatment was higher in cases with MRF ( +) stones. This study represents the results of a large series of infants and children with UL and showed that there are several differences such as underlying metabolic and anatomic abnormalities, clinical course, and stone remission rates between infants and children with urinary stone disease.

Sex and gender differences in chronic kidney disease and access to care around the globe

The difference between sex, the biological construct, and gender, the social construct, may be most evident in settings of vulnerability. Globally, chronic kidney disease is more prevalent among women, but the prevalence of end-stage kidney failure, and especially receipt of kidney replacement therapy, is higher in men. These differences likely reflect a combination of physiological and social/structural risk factors that independently modulate kidney disease and/or its progression. The distribution of the most common risk factors such as hypertension and obesity differ between men and women and may impact disease risk differentially. Social and structural gender-related inequities remain stark across the globe. More women live in poverty, receive less education, and are more dependent on others for health care decision making, but men may have a higher risk of injury, occupational exposures, and less access to screening, prevention, and primary care. In this article, we explore how social determinants of health affect kidney disease risk and access to care differentially across genders, and differently across the globe. We also describe specific challenges experienced by boys and girls with kidney disease, how culture and geography may impact kidney care in places where resources are particularly limited such as sub-Saharan Africa, and give examples of social and structural circumstances that place young men and women at high risk of kidney disease in Mexico and Central America, illustrated by case vignettes. The coronavirus disease-2019 pandemic has raised awareness of pervasive gender-based inequities within all societies. This applies to kidney disease and is not new. The nephrology community must add its voice to the calls for action, for a more just society overall, and for the recognition of the roles of sex and gender as modulators of kidney disease risk and access to care.

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.

Comparison of Renal Stones and Nephrocalcinosis in Children: Findings From Two Tertiary Centers in Saudi Arabia

Background: Renal stones (nephrolithiasis and urolithiasis) and nephrocalcinosis are uncommon in children; however, their incidences in pediatric populations have been increasing. Patients and Methods: This multicenter retrospective study compared the clinical presentation, etiology, and outcomes of childhood nephrolithiasis or urolithiasis with those of nephrocalcinosis. Results: The study included 144 children: 93 with renal stones and 51 with nephrocalcinosis. The mean age at presentation was 72 months and 54 months for children with renal stones and nephrocalcinosis, respectively. A history of consanguinity was found in 65% and 76% of the cases of renal stones and nephrocalcinosis, respectively. Congenital anomalies of the kidneys and urinary tract (CAKUT) were present in 28 and 9.8% of the patients with renal stones and nephrocalcinosis, respectively. The most common symptoms of renal stones were flank pain (29%), hematuria (15%), and dysuria (11%). Urinary tract infection was the primary presentation in the nephrocalcinosis group (18%), followed by failure to thrive (16%), polyuria (12%), and dehydration (12%). The majority of renal stone cases were caused by metabolic disorders, including hyperoxaluria (18%), cystinuria (18%), hypercalciuria (12%), and hyperuricosuria (2%). In contrast, the most common underlying disorders in cases of nephrocalcinosis were familial hypomagnesemia, hypercalciuria, nephrocalcinosis (35%), distal renal tubular acidosis (23%), and Bartter syndrome (6%). Clinical outcomes were significantly better in children with nephrolithiasis/urolithiasis than in those with nephrocalcinosis, who showed radiological evidence of worsening/persistent calcinosis and progressed more frequently to chronic kidney disease (stage II-IV) and end-stage kidney disease. Conclusion: The average age at presentation for children with renal stones was greater than that for those presenting with nephrocalcinosis. More than 25% of the children with renal stones were found to have CAKUT. Nephrocalcinosis was associated with worse clinical outcomes related to kidney function and disease resolution than nephrolithiasis.

Surface analysis of ureteral stent before and after implantation in the bodies of child patients

The aim of this work was to determine which part of a double-J ureteral stent (DJ stents) showed the highest tendency to crystal, calculi, and biofilm deposition after ureterorenoscopic-lithotripsy procedure (URS-L) to treat calcium oxalate stones. Additionally, the mechanical strength and the stiffness of DJ stents were evaluated before and after exposure to urine. Obtained results indicated that the proximal (renal pelvis) and distal (urinary bladder) part is the most susceptible for post-URS-L fragments and urea salt deposition. Both, the outer and inner surfaces of the DJ ureteral stents were completely covered even after 7 days of implantation. Encrustation of DJ stents during a 31-day period results in reducing the Young’s modulus by 27–30%, which confirms the loss of DJ stent elasticity and increased probability of cracks or interruption. Performed analysis pointed to the need to use an antibacterial coating in the above-mentioned part of the ureteral stent to prolong its usage time and to prevent urinary tract infection.

Endoscopic-assisted robotic pyelolithotomy: a viable treatment option for complex pediatric nephrolithiasis

INTRODUCTION AND OBJECTIVE

Endourological and percutaneous approaches are the standard of care for treatment of pediatric urolithiasis. However, in certain situations, an endoscopic-assisted robotic pyelolithotomy (EARP) can be an acceptable alternative. Limited data exist on pediatric EARP; thus, the authors describe their experience.

METHODS

Patient selection: The authors retrospectively analyzed the records of all robotic procedures performed at five institutions from 7/09-10/17 to identify patients who underwent EARP. The authors collected demographics data, indications, operative time, and postoperative complications. Stone composition was reported as the majority composition (≥50%), unless any uric acid or struvite was noted, and those stones were classified as such.

TECHNIQUE

Through a traditional or hidden incision endoscopic surgery (HIdES) robot pyeloplasty approach, the authors are able to easily pass a flexible endoscope through a robotic trocar and into the renal collecting system to perform pyeloscopy or ureteroscopy. Stones were primarily retrieved via the pyelolotomy and, if indicated, treated with laser lithotripsy.

RESULTS

The authors identified 26 patients who underwent EARP in 27 renal units. Median patient age was 12.2 years (interquartile range [IQR] 6.1-14.5 years), and body mass index was 17.5 kg/m² (IQR 16.5-25.4 kg/m²). The median pre-operative dimension of the largest stone was 9.0 mm (IQR 5.8 mm-15.0 mm). Reasons for EARP: 21 (77.8%) concomitant pyeloplasty, four (14.8%) altered anatomy precluding other techniques, and two (7.4%) multiple large stones. Multiple stones were present in 20 renal units (74.1%). Stones were located in the renal pelvis in nine (33.3%), lower pole in 10 (37.0%), ureter in one (3.7%), and multiple locations in seven (25.9%). Hidden incision endoscopic surgery approach was used in 14 (51.9%), and the median operative time was 237.5 min (IQR 189.8-357.8 min) with a median length of stay 1.0 day (IQR 1.0-2.0 days). Stone composition included calcium oxalate in 14 (51.9%), calcium phosphate in five (18.5%), cysteine in two (7.4%), struvite in two (7.4%), and unknown in four (14.8%). Overall stone free status was 19 (70.4%); of the eight (29.6%) renal units with residual stones, four underwent ureteroscopy, two extracorporeal shockwave lithotripsy (ESWL), one spontaneously passed, and one underwent percutaneous nephrolithotomy (PCNL). After secondary treatment, final stone free rate was 96.3%. Complications included stent migration and admission for urosepsis. At a median follow-up of 12 months (IQR 6.2-19.2 months), five (18.5%) had stone recurrence.

CONCLUSIONS

Endoscopic-assisted robotic pyelolithotomy is a reasonable treatment option for select pediatric patients with concomitant ureteropelvic junction obstruction and nephrolithiasis or pediatric patients with stones inaccessible by standard methods.