Medical management of pediatric stone disease

Korean Society of Endourology and Robotics (KSER) recommendation on the diagnosis, treatment, and prevention of urolithiasis

This article provides evidence-based recommendations and expert opinions to aid urologists in making optimal decisions regarding managing urolithiasis in various clinical scenarios. The most frequently asked questions by urologists in their clinical practice have been collected and answered in the form of FAQs; based on the latest evidence and expert opinions. The natural history of urolithiasis is divided into active treatment and silent phases, with the active treatment stage divided into typical and special situations and peri-treatment management. The authors address 28 key questions, offering practical guidance for the proper diagnosis, treatment, and prevention of urolithiasis in clinical practice. This article is expected to be served as a valuable resource for urologists.

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.

Minipercutaneous Nephrolithotomy in the Management of Large and Complex Renal Calculi in Children: How Effective Is It?

Purpose: To evaluate the efficacy and safety of minipercutaneous nephrolithotomy (PCNL) in the management of large and complex calculi in children. Patients and Methods: From May 2017 to April 2021, a total of 41 pediatric cases were diagnosed with large/complex renal stones (partial-total staghorn) and following a detailed biochemical evaluation and thorough radiological examination (plain abdominal radiograph, urinary ultrasound, noncontrast and/or computed tomography), all cases underwent mini-PCNL procedure for the minimal invasive management of these calculi. Preoperative, intraoperative, and postoperative data were analyzed and reported in detail. Results: A total of 41 procedures were performed in 26 boys and 15 girls (male/female = 1.73). While the age of the kids ranged from 2.5 to 10 years (mean 6.74 ± 2.76), mean size of the stones was 16.28 ± 3.43 mm (range 11-24) with a mean stone density value of 816 HU (range 550-1350). Evaluation of the success rates in terms of complete stone clearance on postoperative day 1 revealed that while 73.2% (30/41), residual fragments have been noted in 11 cases (26.8%). Size of the residual fragments ranged from 2 to 7 mm (mean 4.3). Of those children, 10 cases required flexible ureteroscopy for stone removal, and in 1 case, placement of Double-J was adequate for spontaneous passage. During a 3-month follow-up, the stone-free rate (SFR) increased to 100% without any residual fragment left. Conclusions: Mini-PCNL with holmium laser lithotripsy is an effective and safe treatment alternative in the minimal invasive management of large/complex kidney stones in children with high SFRs.

Combined treatment of ureteropelvic junction obstruction and renal calculi with robot-assisted laparoscopic pyeloplasty and laser lithotripsy in children: Case report and non-systematic review of the literature

OBJECTIVE(S)

The incidence of urinary tract stone disease is steadily increasing in both adult and paediatric populations. This condition develops due to different factors: dietary or metabolic alterations, infection, and congenital anatomic malformations. Standard indications and treatments for children are analogous to the ones indicated for adults. Extracorporeal shock wave lithotripsy, ureterorenoscopy and percutaneous nephrolithotomy (PCNL) should be preferred to more invasive techniques. Moreover, the introduction of laparoscopic and robot-assisted laparoscopic approaches have improved surgical outcomes, lowering the bleeding risk with higher stone-free rates, even in complicated cases. Despite these well-known improvements, there are few reports regarding laparoscopic robot-assisted management for urinary tract stone disease in paediatric patients under the age of 10, especially with concomitant treatment of ureteropelvic junction obstruction and multiple calyceal stones.

PATIENT AND METHOD(S)

A 4-year-old child was referred for recurrent right abdominal flank pain, macroscopic haematuria and a previous history of urinary tract infections. A computed tomography of the abdomen showed right ureteropelvic junction obstruction associated with multiple unilateral stones located in the renal pelvis and in the interpolar renal calyces. Due to its complexity, we held a multidisciplinary meeting with paediatric surgeons and nephrologists to determine optimal treatment. As a result, a combined robot-assisted laparoscopic pyeloplasty (LP) and renal calculi holmium laser lithotripsy using a digital flexible ureteroscope through an abdominal robotic trocar was performed. No post-surgical complications were recorded, and the patient was discharged within 48 h following surgery. At subsequent regular follow-up examinations over a period of 24 months, no signs of recurrence were detected for both ureteropelvic junction obstruction and stone disease.

RESULT(S)

Robot-assisted LP with concomitant laser lithotripsy is a reasonable treatment option for designated young paediatric patients with challenging ureteropelvic junction obstruction complicated by urolithiasis, especially in cases where stones are not amenable with standard procedures.

Pediatric stone disease: Current management and future concepts

Treatment of pediatric urolithiasis consists of medical and surgical approaches. The main goal of the treatment is to prevent stone recurrence by avoiding multiple surgical interventions. In recent years, many innovations have been reported in the medical diagnostic evaluation protocol and in surgical treatment. According to recent reports, single mutations could be responsible for a larger proportion of renal stones. This etiologic feature holds the potential to change the management in stone prevention from metabolically directed therapy to more specific approaches. In addition, miniaturized instruments have been adopted in clinical practice. In recent years, minimally invasive endoscopic surgery is the treatment of choice in pediatric urolithiasis. This review aims to assess the current literature on medical and surgical treatment options for pediatric urolithiasis. We also aim to provide an overview of potential future advances.

Which factors affect the success of pediatric PCNL? Single center experience over 20 years

OBJECTIVE

We aimed to investigate the impact of surgeons' experience on pediatric percutaneous nephrolithotomy (PCNL) outcomes.

MATERIALS AND METHODS

Between June 1997 and June 2018, 573 pediatric patients with 654 renal units underwent PCNL for renal stone disease by senior surgeons. Data were divided into two groups, group-1 (n = 267), first ten years period, group-2 (n = 387); second ten years period.

RESULTS

Mean ± SD age of patients was 7.6 ± 4.9 (1-17) years. The stone-free rates (SFR) assessed after 4 weeks were 74.9% vs. 83.4% in group-1 vs. group-2, respectively (p = 0.03). The mean operation time, fluoroscopy time, and the number of patients requiring blood transfusion significantly decreased in group 2 (100.4 ± 57.5 vs. 63.63 ± 36.3, 12.1 ± 8.3 vs. 8.3 ± 5.4, and 24.3% vs. 2.9%; p < 0.001, p < 0.001, and p = 0.002 in group-1 versus group-2, respectively). On multivariate analysis, increasing stone size increased operation time (p < 0.001), fluoroscopy time (p < 0.001), intraoperative and postoperative blood transfusion rates (p = 0.006 and p = 0.018, respectively), and hospital stay (p = 0.002) but was not associated with change of glomerular filtration rate (GFR) (p = 0.71). Sheath size also correlated with increased fluoroscopy time (p < 0.001), operation time (p < 0.001), intraoperative blood transfusion (p < 0.001) and hospital stay, but sheath size did not affect postoperative blood transfusion (p = 0.614) or GFR change (p = 0.994).

CONCLUSIONS

The percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure and is well accepted because of its lower complication rate and high efficiency for pediatric patients. Stone and sheath size are predictive factors for blood loss and hospital stay. During 20 years, our fluoroscopy time, operation time, blood loss, and complication rates decreased, and stone-free rate increased.

Diagnosis and management of non-calcium-containing stones in the pediatric population

Compared to adults, urolithiasis is less common in children, with a definite rise in incidence, especially among young adults (Tasian et al. in Clin J Am Soc Nephrol 11:488, 2016). In the last 25 years, the incidence in children has increased by approximately 6-10% annually, for reasons still unknown, with an associated significant increase in related health care-related expenditures (Hyams and Matlaga in Transl Androl Urol 3(3):278-83, 2014). It has been shown that there is twice as high a risk of chronic kidney disease (CKD) or end stage renal disease (ESRD) in stone formers compared to non-stone formers (Tasian et al. 2016). While calcium-containing stones are by far the most common category of stone encountered in both children and adults, non-calcium stones are more common in children than adults and have been shown in several studies to be associated with greater morbidity and lower renal function than calcium stones (Issler et al. in BMC Nephrol 18(1):136, 2017; Gambaro et al. in J Urol 198:268-273, 2017). This could be related to the challenges in the management of non-calcium-containing stones due to associated infection or metabolic derangements, further leading to recurrence and loss of renal function. There is currently a gap in our understanding of how to appropriately and effectively encounter and manage patients with non-calcium-containing stones, as such cases are encountered less frequently. Identification of stone composition and appropriate management is very important to reduce serious complications and recurrence, especially in non-calcium stones. We present a review of diagnosis and management of non-calcium-containing stones in the pediatric population, in hopes of providing more clarity to providers and promoting a consideration of non-calcium stone composition with all children presenting with urolithiasis.

Trends of intervention for paediatric stone disease over the last two decades (2000-2015): A systematic review of literature

OBJECTIVE

To ascertain the publication trends of interventions for paediatric kidney stone disease (KSD) we conducted a systematic review of literature over the last 16 years.

PATIENTS AND METHODS

With a rise of paediatric KSD and related interventions, a systematic review using PubMed was done over the last 16 years for all published papers on 'Paediatric stone disease intervention - ureteroscopy (URS), shockwave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), open stone surgery, and laparoscopic stone surgery'. The search was limited to English language articles with a published abstract, whilst case reports, animal and laboratory studies, were excluded. We also analysed the data in two time periods, period-1 (2000-2007) and period-2 (2008-2015).

RESULTS

During the last 16-years, 339 papers were published on paediatric stone disease intervention on PubMed. This included papers on URS (95), PCNL (97), SWL (102), open stone surgery (34) and laparoscopic stone surgery (11). During period-1 and period-2 there were 30 and 65 papers on URS, 16 and 81 papers on PCNL, 33 and 60 papers on SWL, nine and 25 papers on open surgery, respectively. When comparing the two periods, there were 92 published papers for all interventions in period-1 and this had risen almost threefold to 247 papers in period-2.

CONCLUSIONS

Our systematic review shows that intervention for KSD in the paediatric age group has risen over the last 8 years. Whilst URS, SWL, open surgery and laparoscopic surgery have all doubled, PCNL has risen fivefold reflecting an increase in the new minimally invasive PCNL techniques.

What do we know about pediatric renal microlithiasis?

Renal or calyceal microlithiasis is a common disorder with increasing prevalence especially in infants and younger children. The main presenting symptoms and the underlying metabolic abnormalities of renal microlithiasis are similar to renal stone. Although renal microlithiasis is considered as a main problem of the health system with diverse etiologies, our information about its natural course is very limited. Hence, further investigations to make an appropriate clinical approach to this entity is mandatory. Also, general practitioners, pediatricians, nephrologists and urologists have to be well educated regarding renal microlithiasis for early diagnosis, appropriate evaluation and proper management of this entity. In this review study, we focused on collection of the present information about different aspects of renal microlithiasis in children.

Paediatric ureterolithotripsy: Tips and tricks - Experience at a single center

BACKGROUND

Paediatric stone disease is very common in certain regions of India. Traditionally, the endourology for the stones even in paediatric age group is managed by adult urologist and paediatric surgeons tend to do open surgeries. The nonavailability of paediatric size equipments and lack of training at the teaching and tertiary care paediatric surgical centers in India are factors due to which there is continued apathy of paediatric surgeons to endourology. The aim of this study was to discuss the feasibility of paediatric ureterolithotripsy for successful procedure. We introduced the paediatric ureterolithotripsy as per the predecided indications of stone size up to 15 mm in paediatric ureterolithiasis at a tertiary care center in rural set up.

SUBJECTS AND METHODS:

Patients up to 18 years of age presenting with ureterolithiasis and not responding to conservative treatment or who needed endourological intervention were included in the study.

RESULTS:

Thirty-one patients underwent uretero lithotripsy (URSL) for ureteric calculus with more than 95% clearance rate.

CONCLUSIONS:

Single-stage paediatric ureterolithotripsy is quite feasible and effective in achieving the stone clearance in paediatric ureterolithiasis.

The use of alpha-1 adrenergic blockers in children with distal ureterolithiasis: a systematic review and meta-analysis

INTRODUCTION

Urinary lithiasis is the main urologic cause of emergency treatment in adult patient. In the past years, the incidence in children population has increased. However, literature about the use of alpha-1 adrenergic blockers in pediatric population with distal ureterolithiasis is still scarce. The drug acts by decreasing ureter contractions, especially in the distal portion, facilitating calculus expulsion.

OBJECTIVE

This review has the objective to evaluate the use of alpha-1 adrenergic blockers as medical expulsive treatment in children with distal ureterolithiasis.

EVIDENCE ACQUISITION

An electronic literature search was performed using the MEDLINE, COCHRANE, and LILACS databases. We further searched manually the references of the primary studies. Searches were concluded on October 4th, 2014. Articles were selected, independently and in pairs, by the respective titles and summaries. Any divergence was resolved by consensus.

EVIDENCE SYNTHESIS

Alpha-1 adrenergic antagonists increased the probability of calculus expulsion by 27% (NNT=4). Calculi smaller than 5mm, increased by 33% (NNT=3). Larger than 5mm, increased by 34% (NNT=3).

CONCLUSION

Alpha-1 adrenergic blocker use is related with a greater incidence of expulsion of ureteral calculi, smaller or greater than 5mm, and fewer episodes of pain when compared to ibuprofen. However it is necessary larger samples to enhance the power analysis of the expulsion of ureteral calculi larger than 5mm and the episodes of pain.

PATIENT SUMMARY

This review analyzed the outcome of alpha adrenergic antagonist in children with ureteral calculi. We conclude that it is the best medicine for use, since it helps the expulsion of the stone.

Treatment alternatives for urinary system stone disease in preschool aged children: results of 616 cases

INTRODUCTION

The treatment of stone disease is mostly similar in those adult and children. The standard treatment procedures are as follows: extracorporeal shock wave lithotripsy (ESWL), ureterorenoscopy (URS), percutaneous nephrolithotomy (PCNL), and laparoscopic surgery in selected cases. Open surgery (OS) is another option particularly in such cases with anatomic abnormalities of urinary tract.

OBJECTIVE

The present study aims to provide comparative results of stone removal procedures in preschool aged patients who were diagnosed with urinary system stone disease.

STUDY DESIGN

The retrospective data of 616 pediatric preschool patients consulted with urinary system stone disease between January 2009 and July 2013 were evaluated. All patients were evaluated with Kidney-Ureter-Bladder (KUB) Xray and abdomino-pelvic ultrasound. Intravenous pyelography, unenhanced computed tomography (CT), and renal scintigraphy were performed when needed. Patients were categorized according to the procedures as: Group ESWL, Group URS, Group PNL, Group micro-PNL and Group OS. Following the procedures, opaque residual stones were evaluated with KUB Xray, and non-opaque residual stones were evaluated with unenhanced CT.

RESULTS

In groups (ESWL, URS, PNL, micro-PNL, OS), the stone-free rate was 68%, 66%, 85%, 100% and 94 %, respectively. The stone analysis were observed as, calcium oxalate in 377 patients (61.2%), uric acid in 106 patients (17.2%), infection stone in 73 patients (11.8 %), and cysteine in 60 patients (9.7%). There was no significant difference in stone analysis between the groups (p > 0.05) (Table).

DISCUSSION

Minimally invasive procedures are frequently preferred in the pediatric age urinary system stone disease. These procedures are ESWL, PCNL, and ureteroscopy [10,11]. Open surgery is reserved only for rare cases [12]. Similarly the current literature, 18 (2.9%) patients had anatomical anomaly and had high complex stone burden were treated with open surgery in our study. ESWL is a preferred treatment method for pediatric urolithiasis patients with a stone size <20 mm, and the rate of stone-free after ESWL ranges between 57 and 92% [13]. In a study showed the effect of stone size on the success rate in ESWL, the success rate was 91% for stones <10 mm, and 75% for stones >10 mm [15]. In the present study, stone-free rate was noted as 68% on 15 mm or lower stone size. PNL is commonly used to treat stone disease in preschool children [18-20]. In the beginning, urologists hesitated to use instruments suited for adults in case of pediatric kidneys. While some authors accept a cut-off value of 24 F for tract dilatation in the pediatric age, Desai et al. recommended a threshold value <22 F [19,21]. In our study, we used adult PNL instruments in the early period, whereas mini-PERC was performed in the later years. The success rate in PNL group was found as 85%. In recent years, the micro-PNL procedure has been developed to reduce/prevent the complications of standard PNL. In our study, the success rate was calculated as 100% with micro-PNL. This study has certain limitations. The major limitation of our study is its retrospective nature. In addition, sample size of micro-PNL group is fewer than other groups.

CONCLUSION

The goal of kidney stone treatment is to achieve minimal kidney damage and a high success rate. Thus, the procedures are important in the pediatric age group where life expectancy is high, and particularly in the preschool age group.

A case of recurrent renal aluminum hydroxide stone

Renal stone disease is characterized by the differences depending on the age, gender, and the geographic location of the patients. Seventy-five percent of the renal stone components is the calcium (Ca). The most common type of the stones is the Ca oxalate stones, while Ca phosphate, uric acid, struvite, and sistine stones are more rarely reported. Other than these types, triamterene, adenosine, silica, indinavir, and ephedrine stones are also reported in the literature as case reports. However, to the best of our knowledge, aluminum hydroxide stones was not reported reported before. Herein we will report a 38-years-old woman with the history of recurrent renal colic disease whose renal stone was determined as aluminum hydroxide stone in type. Aluminum mineral may be considered in the formation of kidney stones as it is widely used in the field of healthcare and cosmetics.

Bladder calculus formation on the tip of a migrated disused ventriculoperitoneal shunt

Bladder stones in children are rare. They generally occur in children with one or more predisposing risk factors to stone formation. In this unique case report we discuss the formation and successful endoscopic treatment of a large stone in a neuropathic bladder on the tip of a migrated VP shunt.

[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.

Urinary stone disease in the first year of life: is it dangerous?

PURPOSE

We have evaluated the clinical, radiological and metabolic features of infantile urolithiasis (UL).

MATERIALS AND METHODS

We have reviewed the medical records of 93 children who were diagnosed as having UL before 1 year of age. We recorded patient demographics, the age at diagnosis, presenting symptoms, family history, the localizations and dimensions of stones, urinary metabolic examinations, as well as physical, laboratory, and radiologic findings. Our secondary objective was to compare some features of this group with those of older children with UL followed-up in the same clinic which were previously reported.

RESULTS

We evaluated 93 children referred to our pediatric nephrology clinics. A family history of UL was 56.2 % in the study group. Resolution of stones was observed in 30.1 % of the cases. Urinary tract infections (UTIs) were detected in 65.9 % of females and 46.2 % of males. At least one urinary metabolic abnormality was found in 79.5 % of all the children. Most commonly seen metabolic abnormality was hypercalciuria. In all patients stones were located in kidneys except one infant who had an ureteral stone together with a kidney stone. Fifteen (16.1 %) children had an accompanying systemic disorder.

CONCLUSIONS

Among pediatric urinary stone diseases infantile UL can be regarded as a separate clinical entity. Coexistence of systemic disorders and anatomic anomalies at high frequencies may indicate a role of distinct pathogenetic mechanisms. In addition, high rates of UTIs and metabolic abnormalities in this age group justify screening for these parameters during follow-up of these children.

Urolithiasis in children: medical approach

Childhood urolithiasis is an evolving condition with an increasing incidence and prevalence over the last 2 decades. Over that time the underlying cause has shifted from predominantly infectious to metabolic in nature. This review describes the pathophysiology, underlying metabolic abnormalities, clinical presentation, evaluation, and management of childhood urolithiasis. A comprehensive metabolic evaluation is essential for all children with renal calculi, given the high rate of recurrence and the importance of excluding inherited progressive conditions.

Urine risk factors in children with calcium kidney stones and their siblings

Calcium nephrolithiasis in children is increasing in prevalence and tends to be recurrent. Although children have a lower incidence of nephrolithiasis than adults, its etiology in children is less well understood; hence, treatments targeted for adults may not be optimal in children. To better understand metabolic abnormalities in stone-forming children, we compared chemical measurements and the crystallization properties of 24-h urine collections from 129 stone formers matched to 105 non-stone-forming siblings and 183 normal, healthy children with no family history of stones, all aged 6 to 17 years. The principal risk factor for calcium stone formation was hypercalciuria. Stone formers have strikingly higher calcium excretion along with high supersaturation for calcium oxalate and calcium phosphate, and a reduced distance between the upper limit of metastability and supersaturation for calcium phosphate, indicating increased risk of calcium phosphate crystallization. Other differences in urine chemistry that exist between adult stone formers and normal individuals such as hyperoxaluria, hypocitraturia, abnormal urine pH, and low urine volume were not found in these children. Hence, hypercalciuria and a reduction in the gap between calcium phosphate upper limit of metastability and supersaturation are crucial determinants of stone risk. This highlights the importance of managing hypercalciuria in children with calcium stones.

Extracorporeal shock wave lithotripsy as first line treatment for urinary tract stones in children: outcome of 500 cases

PURPOSE

The continued evolution of stone treatment modalities, such as endourologic procedures, open surgery and shock wave lithotripsy, makes the assessment of continuous outcomes are essential. Pediatric urolithiasis are an important health problem allover the world, especially in Middle East region. We evaluate the safety, efficacy and factors affecting success rate and clearance of stones in children treated with shock wave lithotripsy.

PATIENT AND METHODS

Between 2005 and 2010, a total of 500 children with stones in the upper urinary tract at different locations were treated by Extracorporeal shock wave lithotripsy (ESWL) in our department, Sohag University, Egypt. We have used the Siemn's Lithostar Modularis machine, Germany. A total of 371 boys and 129 girls with the average age of 8.63 ± 5 years, and a range from 9 months to 17 years were included in this study. Diagnosis of their urinary calculi was established either by the use of abdominal ultrasound, plain X-ray, intravenous urography, or CT scan. The stones were located in the kidney in 450 (90%) patients; 298 (66%) pelvic, 26 (5.7%) upper calices, 57 (12.6%) mid calices, and lower calices in 69 (15.3%) patients. The average of their stone sizes was 12.5 ± 7.2 mm. The other 50 children their stone were located in the proximal ureteral stones in 35 patients (70%); middle third in 5 (10%) patients and in the distal ureter in 10 (20%) patients. The average ureteral stone size was 7.5 ± 3.2 mm. All children were treated under general anesthesia with adequate lung and testes shielding using air foam. We treated the distal ureteral stones of young children in the supine position through greater sciatic foramen and lesser sciatic foramen as the path of shockwave instead of prone position, which is not a comfortable or natural position and could adversely affect cardiopulmonary function especially under general anesthesia. Localization was mainly done by ultrasound, and X-ray was only used to localize ureteral calculi. For follow-up, we have used abdominal ultrasound, plain X-ray, and CT scan if needed to confirm stone disintegration and clearance.

RESULTS

The overall success rate for renal and ureteral calculi was 83.4 and 58.46%, respectively. The re-treatment rate was 4% in renal group and 28% for the ureteral group. No serious complications were recorded in our patients. Minor complications occurred in 15% of our patients; renal colic was reported in 10% of our treated patients, and repeated vomiting was reported in 5% that respond to antiemetics. In the renal group; children with history of pervious urologic surgical procedures had low success rate of stone clearance after ESWL. In the ureteral group stone burden, stone location, had a significant impact on stone clearance outcome.

CONCLUSION

This study showed that SWL in pediatric age group for both renal and ureteral stone is cost effective, safe with an acceptable re-treatment rate; however children with large stone burden or previous urologic surgery have low success rate.

Does child's age affect interval to stone-free status after SWL? A critical analysis

OBJECTIVE

To evaluate the success rates and complications of extracorporeal shock wave lithotripsy (ESWL) in children with renal stones in an age-dependent manner.

METHODS

From 2006 to 2010, 164 children (male/female ratio 1:3) with renal calculi have been treated with ESWL (PiezoLith3000 lithotripter). The children were divided into 2 age groups: group 1, 0-6 years old (n = 133); and group 2, 7-15 years (n = 31). The patient- and treatment-related parameters were recorded for comparative evaluation. The success of ESWL in terms of the stone-free rates, additional procedures, and complications were comparatively evaluated. The data were analyzed statistically.

RESULTS

The mean age of groups 1 and 2 was 28 ± 18 months (range 4-71) and 119 ± 28 months (range 73-178), respectively. Although general anesthesia was used for all patients in group 1, 29% of the patients were treated under neuroleptic anesthesia in group 2. During the 3-month follow-up period, the complete stone-free rate was 94.7% (126 of 133), and treatment was unsuccessful in 7 patients (5.3%) in group 1. The corresponding data were 87% (27 of 31; P = .222) and 4 (13%; P = .089) in group 2. The stone-free rate after the first session was 67.6% (90 of 133) and 38.7% (12 of 31) in groups 1 and 2, respectively (P = .004). The mean number of ESWL sessions applied was 1.6 (range 1-5) and 2.9 (range 1-6) in groups 1 and group 2, respectively (P = .0001). No major complications were noted.

CONCLUSION

Our results have demonstrated that ESWL is highly successful in the management of renal calculi in children. Compared the outcomes by age, the younger children become stone free more quickly than the older children with fewer ESWL sessions.

Comparative analysis of nephrolithiasis in otherwise healthy versus medically complex gastrostomy fed children

PURPOSE

The purpose was to compare nephrolithiasis in healthy versus medically complex gastrostomy fed children.

MATERIALS AND METHODS

Children with nephrolithiasis with and without gastrostomy were identified by database searches from 1999 to 2009. Gastrostomy fed stone formers (GSF) were compared to an age-matched cohort of non-gastrostomy-fed stone formers (NGSF) for demographic and clinical data.

RESULTS

16 neurologically impaired GSF (10M:6F), mean age 10.4 years (range 1.7-17.5 years), were compared to 32 matched neurologically intact NGSF. Compared to NGSF, GSF had significantly higher urine pH (6.93 vs 6.23, p = 0.001) and larger stones (14.5 vs 6.9 mm, p = 0.02) more commonly composed of calcium phosphate (7/11, 64% vs 3/28, 11%, p = 0.002). 15/16 (94%) of GSF were immobile while 0% of NGSF were immobile. GSF had lower l-spine bone density Z-scores (-3.02 vs -1, p = 0.002) but an equal rate of hypercalciuria (2/7, 29% vs 7/24, 29%, p = NS). Contributing lithogenic factors in 8/16 (50%) GSF included urinary tract infection (UTI) (5), lithogenic medications (2), and xanthinuria (1).

CONCLUSIONS

Stone disease in GSF is multifactorial, and half of our study group had an identifiable risk factor for nephrolithiasis. A recurring pattern of alkaline urine and calcium phosphate stone formation was evident. GSF did not have higher rates of hypercalciuria despite chronic immobilization and markedly lower bone density. An awareness of the potential risk factors identified is mandatory for this vulnerable population.

Clinical practice: surgical approaches to urolithiasis in children

The incidence of urolithiasis in children is increasing. Adequate knowledge of treatment modalities and surgical options is therefore essential for every pediatrician. Surgical approaches to urolithiasis in children continue to evolve with advancements in technology and sophistication of current equipment and techniques. Perhaps the most significant development in new techniques is the advent of robotic-assisted laparoscopy. This review, for the general pediatrician, summarizes the most recent pediatric data and guidelines for surgical approaches to treatment of urolithiasis.

The predicted increased cancer risk associated with a single computed tomography examination for calculus detection in pediatric patients compared with the natural cancer incidence

OBJECTIVES

The objective of the study was to estimate the increased lifetime cancer risk associated with a single computed tomography (CT) examination for calculus detection in pediatric patients and compare it with the lifetime natural cancer risk.

METHODS

We used the program CT-Expo to calculate the radiation doses to various abdominal and pelvic organs for age-appropriate pediatric renal stone CT examination protocols used at our institution. Using the Biological Effects of Ionizing Radiation (BEIR) VII report, we estimated the lifelong cancer risk for these organs and compared it with the natural cancer risk for the same organs as predicted by the Surveillance, Epidemiology and End Results data from the National Cancer Institute.

RESULTS

For children 10 years or younger at the time of the examination, about 3 radiation-induced cancers are predicted for every 1000 naturally occurring cancers, and for children 15 years old, about 2 radiation-induced cancers are predicted for every 1000 naturally occurring cancers. The radiation dose from this examination is approximately equivalent to 1 to 2 years of background radiation.

CONCLUSIONS

The ratio of the risk for any abdominal and pelvic cancer due to a single CT examination for calculus detection to the risk of a naturally occurring cancer over the lifetime of a child is estimated to be 2/1000 to 3/1000. With this information, the emergency department pediatrician can more effectively counsel parents about the risk-benefit aspects of the CT examination for renal calculus disease in their children.

Increasing incidence of kidney stones in children evaluated in the emergency department

OBJECTIVE

To test the hypothesis that there is an increase in the incidence of childhood nephrolithiasis in the state of South Carolina.

STUDY DESIGN

We analyzed demographic data from a statewide database on incidence of kidney stones from emergency department data and financial charges. Data were compared with population data from the US Census to control for population growth.

RESULTS

There was a significant increase in the incidence of kidney stones in children between 1996 and 2007. The greatest rate of increase was seen in adolescents, pre-adolescents, and Caucasian children. Infants, toddlers, and African-American children did not show significantly increased incidence in the period. Girls show a growing predominance in our population. The amount of money charged for care of children with kidney stones has gone up >4-fold in our state.

CONCLUSION

The incidence of kidney stone disease has risen dramatically in the state of South Carolina since 1996. Further studies investigating potential contributing factors are needed to prevent this costly and painful condition.

History, epidemiology and regional diversities of urolithiasis

Archeological findings give profound evidence that humans have suffered from kidney and bladder stones for centuries. Bladder stones were more prevalent during older ages, but kidney stones became more prevalent during the past 100 years, at least in the more developed countries. Also, treatment options and conservative measures, as well as 'surgical' interventions have also been known for a long time. Our current preventive measures are definitively comparable to those of our predecessors. Stone removal, first lithotomy for bladder stones, followed by transurethral methods, was definitively painful and had severe side effects. Then, as now, the incidence of urolithiasis in a given population was dependent on the geographic area, racial distribution, socio-economic status and dietary habits. Changes in the latter factors during the past decades have affected the incidence and also the site and chemical composition of calculi, with calcium oxalate stones being now the most prevalent. Major differences in frequency of other constituents, particularly uric acid and struvite, reflect eating habits and infection risk factors specific to certain populations. Extensive epidemiological observations have emphasized the importance of nutritional factors in the pathogenesis of urolithiasis, and specific dietary advice is, nowadays, often the most appropriate for prevention and treatment of urolithiasis.

Clinical and metabolic features of urolithiasis and microlithiasis in children

We evaluated the clinical, radiological and metabolic features of 162 children with urolithiasis or microlithiasis who had been referred to our pediatric nephrology clinics between 1998 and 2008 with suspected urolithiasis. The medical histories of these children (78 girls, 84 boys), who ranged in age from 2 months to 16 years (mean age 5.59 +/- 0.35 years), were reviewed retrospectively for clinical and metabolic features of urinary tract calculi. Urinary tract infections (UTI) were present in 45.9% of the cases. The most common presenting symptoms were flank pain or restlessness (25.3%) and hematuria (21.6%), followed by UTI (16%), whereas 23.5% of the cases were detected incidentally during evaluation for other medical conditions. Other symptoms at presentation included dysuria, passing stones, penile edema, enuresis, vomiting and anorexia. Urine analysis revealed metabolic abnormalities in 87% of the cases, including hypercalciuria (33.8%), hypocitraturia (33.1%), hyperoxaluria (26.5%), hyperuricosuria (25.4%), hypocitraturia + hypercalciuria (21.1%), hyperphosphaturia (20.8%) and cystinuria (5.7%). Almost 50% of the patients had a positive family history for urolithiasis. The most frequently involved site was in the kidneys (86%). Ureters and bladder were involved in 12 and 2% of the cases, respectively. A family history of urolithiasis, presenting symptoms and underlying metabolic abnormalities were similar for microlithiasis and the patients with larger stones. However, in our study population, microlithiasis was mainly a disease of young infants, with a greater chance for remission and often not associated with structural changes. The presenting symptoms of urolithiasis show a wide spectrum, so that a high index of suspicion is important for early detection. A metabolic abnormality can be identified in 87% of cases of urolithiasis. Detection of microlithiasis may explain a number of symptoms, thus reducing invasive diagnostic procedures and allowing early recognition of metabolic abnormalities. These results draw attention to the importance of screening for UTIs in patients with urolithiasis.

Pediatric stone disease

Urinary stone disease is less common in children than adults. Although many aspects of pediatric stone disease are similar to that of adults, there are unique concerns regarding the presentation, diagnosis, and management of stone disease in children. We present a review of the increasing prevalence of pediatric stone disease, the diagnostic concerns specific to children, recent results from pediatric series regarding the expectant management and surgical treatment of stones, metabolic evaluation, and current research on the genetics of nephrolithiasis.

Urolithiasis with topiramate in nonambulatory children and young adults

Urolithiasis occurs infrequently in the pediatric population, where metabolic factors play a primary role in the pathogenesis of stone formation. Topiramate, an antiepileptic drug, is associated with a kidney stone in 1.5% of patients in published clinical trials. However, this risk may be much higher in certain populations with multiple preexisting risk factors. We performed a retrospective review of all nonambulatory and neurologically impaired individuals in a long-term care facility. Three groups were involved: those with no exposure to antiepileptic drugs, those on antiepileptic drugs other than topiramate, and those who had been treated with topiramate. Thirteen of 24 (54%) individuals on topiramate monotherapy or polytherapy developed clinical evidence of urolithiasis after a mean duration of 36.4 months. Our results suggest that nonambulatory and neurologically impaired individuals in a long-term care facility appear to be at higher risk of developing kidney stones with topiramate than previously reported.

Pediatric urinary stone disease--does age matter?

PURPOSE

It has been proposed that younger children are less likely to pass renal calculi spontaneously, and that children younger than 10 years are more likely to have an identifiable metabolic abnormality and subsequently a higher risk of recurrence. We report our clinical outcomes in children with urinary calculi, specifically examining these factors.

MATERIALS AND METHODS

We performed a retrospective review of all pediatric patients diagnosed with renal or ureteral calculi at our institution between 2000 and 2007. Of 150 patients evaluated and treated during this period 80 (86 stones) had sufficient followup data to be included. Patients were divided into 2 groups according to age, namely 10 years or younger and older than 10 years. There were 39 patients in the younger group and 41 patients in the older group. Stone size and location, successful passage or intervention, recurrence and 24-hour urine metabolic study results were recorded.

RESULTS

Of the younger cohort stones were ureteral in 43% and renal in 57%. The opposite trend was seen in older patients, with 69% having ureteral and 31% having renal stones (p = 0.02). Mean stone size (greatest dimension) did not differ significantly between the older and younger groups (6.9 mm vs 5.5 mm, p = 0.17). Overall stone passage rate was 34% for younger and 29% for older patients (p = 0.65). No significant mean size differences in passed stones existed between the groups (3.2 mm vs 2.5 mm, p = 0.31). Overall younger vs older ureteral stone passage rate was 37% vs 41% (p = 0.58), and for renal stones it was 32% vs 0%. Stones recurred in 7 younger and 6 older patients.

CONCLUSIONS

Younger children were more likely to present with renal stones, while older children had more ureteral stones. Overall children 10 years old or younger are as likely to pass stones as older children. Renal stones are more likely to be successfully managed expectantly in younger children. Metabolic abnormalities and stone recurrences are observed at similar rates between younger and older children.

Shockwave lithotripsy and endourological management of urinary calculi in children: a single-center 10-year experience

PURPOSE

Shock wave lithotripsy (SWL) and endourological techniques revolutionized the management of pediatric urolithiasis. We sought to assess the impact of new technology and local practice in the treatment of pediatric urolithiasis during a 10-year period.

MATERIALS AND METHODS

Between 1997 and 2006, 125 children (90 boys and 35 girls), aged 18 months to 15 years, were managed in our department for urolithiasis. Stone localization, stone composition, presence of anatomic abnormalities, and treatment modality were evaluated retrospectively.

RESULTS

In 102 children, the stone was located in renal pelvis (0.5-45-mm diameter), in eight in the renal pelvis and one in the calyx; three had staghorn calculi; and 12 had ureteral stone (4-12-mm diameter). Ninety-three of 125 children underwent a total of 108 SWL sessions. Stone size ranged from 0.5 to 35 mm. The stone-free rates were 86%, 92%, and 96% after first, second, and third SWL session, respectively. Ureteroscopy was performed in 12/125 children, and 10/12 (83.5%) were rendered stone free. Nine of 125 children underwent percutaneous nephrolithotomy, and four of nine were stone free (44.5%), although five of the nine children (55.5%) required SWL for residual stone fragments. Open surgery was performed as initial procedure in 11 (9%) children. In 9 of 11 children, ureteropelvic junction obstruction was corrected simultaneously. Open surgery was followed by SWL in 3 of 11 patients. Two of three patients with staghorn calculi underwent nephrolithotomy and SWL and one of three with cysteinuria was managed with SWL.

CONCLUSIONS

SWL and endourological techniques are safe and effective in managing urolithiasis in pediatric patients. These minimally invasive methods reduced dramatically the cases of open surgery, which should be undertaken mainly in coexisting anatomic abnormalities.

[Urolithiasis in children--rational diagnosis, therapy, and metaphylaxis]

With a proportion of 1-5%, children constitute only a small number of all patients with urolithiasis. Nevertheless, pediatric stone disease is an important health care problem because of the high recurrence rate and the threat of progredient renal function impairment with consecutive loss of quality of life. Modern therapies, especially extracorporeal shock wave lithotripsy (ESWL), ureteroscopy (URS), and percutaneous nephrolithotomy (PCNL), have caused a revolution in the operative treatment spectrum. Open surgery is required for stone removal only rarely, such as for the simultaneous repair of urinary tract anomalies. The minimally invasive modalities of modern stone therapy - mainly ESWL as the treatment of first choice - have led to widespread disregard of stone metaphylaxis. The important principle that says an urinary stone is just a symptom and not the cause of the disease is often forgotten. So it must be noted that despite the high standard of care in Germany, not all problems regarding urinary stone disease are being resolved, particularly in childhood. This article presents the current knowledge of the most important aspects of stone therapy and the methods of treatment in children.

Etiology of nephrocalcinosis in northern Indian children

This retrospective survey examines the etiology of nephrocalcinosis (NC) in 40 patients (26 boys), over an 8-year period. The median age at onset of symptoms and presentation was 36 months and 72 months, respectively. Clinical features included marked failure to thrive (82.5%), polyuria (60%) and bony deformities (52.5%). The etiology of NC included distal renal tubular acidosis (RTA) in 50% patients and idiopathic hypercalciuria and hyperoxaluria in 7.5% each. Other causes were Bartter syndrome, primary hypomagnesemia with hypercalciuria, severe hypothyroidism and vitamin D excess. No cause for NC was found in 12.5% patients. Specific therapy, where possible, ameliorated the biochemical aberrations, although the extent of NC remained unchanged. At a median (range) follow up of 35 (14-240) months, glomerular filtration rate (GFR) had declined from 82.0 (42-114) ml/min per 1.73 m2 body surface area to 70.8 (21.3-126.5) ml/min per 1.73 m2 body surface area (P = 0.001). Our findings confirm that, even with limited diagnostic facilities, protocol-based evaluation permits determination of the etiology of NC in most patients.

Management of pediatric stone disease

Pediatric and adult stone disease differs in both presentation and treatment. Children can present with a wide range of symptoms varying from flank pain and hematuria to nonspecific symptoms such as irritability and nausea. Although ultrasonography and plain radiographs can play a role in diagnosis and follow-up, the standard of care for a child who presents to the emergency department with a history suggestive of a stone is noncontrast spiral CT. Because there is a high yield in identifying predisposing factors in children with urolithiasis and high recurrence rates, metabolic evaluation of every child with a urinary stone should be undertaken and medical treatment should be given if necessary. With recent advances in technology, stone management has changed from an open surgical approach to less invasive procedures such as extracorporeal shock-wave lithotripsy and endoscopic techniques. Herein, we present a review of the recent literature and offer our own preferences to approaches for treatment.

Urinary metabolic evaluations in normal and stone forming children

PURPOSE

Urinary stone disease is relatively rare in children and urinary metabolic evaluations have been the standard in our practice. We have previously reported a high rate of urinary metabolic abnormalities in stone forming children. We compared urinary chemistry values in normal and stone forming children.

MATERIAL AND METHODS

A prospective study was performed to assess urinary metabolic profiles in children with no history or a family history of urinary calculi. The 24-hour urine collections were performed and evaluated at an outside central laboratory. Urine chemistry studies were adjusted for creatinine. The data were compared to those on a historical cohort of calcium stone forming children.

RESULTS

A total of 58 samples from normal children and 142 from stone forming children were evaluated. Mean age was 10 years in normal children and 12 years in stone forming children. of the normal and stone forming children 45% and 51%, respectively, were female. Supersaturation levels of calcium oxalate as well as calcium to creatinine levels were significantly higher in children with stones. No data confounding by age or sex was identified by stratification.

CONCLUSIONS

There are significant differences in urinary metabolic evaluations between normal and stone forming children. This may allow more precise treatment to prevent recurrent stone episodes. We continue to perform metabolic evaluations in all children with documented urolithiasis.