Pediatric urolithiasis in Armenia: a study of 198 patients observed from 1991 to 1999

Current Status and Prospects of Pediatric Stone Disease: A Bibliometric and Visualization Study

Pediatric stone disease, once considered rare, has emerged as a significant research area in the past two decades due to a sharp increase in its incidence. Understanding the evolving epidemiology and treatment strategies for pediatric stone disease is crucial for enhancing child health protection. This study aims to summarize the advancements in pediatric stone disease research over the last two decades through bibliometric analysis. We conducted a comprehensive search in the Web of Science Core Collection (WoSCC) for literature on pediatric stone disease from January 1, 2000 to February 20, 2024. Econometric analyses were performed using tools such as VOSviewer, CiteSpace, and the R package "bibliometrix." Our search yielded 1,208 publications, predominantly from the United States and Turkey, showing an annual increase in publications on pediatric stone disease. Leading research institutions include Dicle University, Children's Hospital of Philadelphia, and the University of Pennsylvania, with the Journal of Pediatric Urology publishing the highest number of articles. The most prolific authors were C.P. Nelson and B. Hoppe, with Caleb P. Nelson being the most co-cited author. Research themes primarily focused on risk factors and therapeutic approaches for pediatric stone disease. Emerging research hotspots are identified by keywords such as mechanism, mini-percutaneous nephrolithotomy, recurrence, and retrograde intrarenal surgery. The study forecasts a continued upward trend in global research on pediatric stone disease, with future studies likely to delve deeper into risk factors and novel therapeutic methods.

Metabolic and Clinical Characteristics of Children with Urolithiasis from Southern India

OBJECTIVE

To study the etiological profile and patterns of clinical presentations of urolithiasis (UL) in children.

METHODS

This observational study included patients <18 y with UL, who were referred to the pediatric nephrology clinic. Clinical features, family history, consanguinity and estimated glomerular filtration rate (eGFR) at presentation and follow-up were recorded. The children were evaluated using relevant blood and urine investigations.

RESULTS

A total of 72 children with UL were evaluated for the study. The etiology of UL (n = 72) included hyperoxaluria (n = 25; 34.7%), idiopathic hypercalciuria (n = 21; 29.2%), idiopathic hyperuricosuria (n = 3; 4.2%), cystinuria (n = 3; 4.2%), urate transporter defect (n = 2; 2.8%) and mixed stones (predominant component calcium oxalate) (n = 9; 12.5%). No etiology was detected in 4 cases (5.5%). Common presenting complaints included flank pain (n = 41; 56.7%), hematuria (n = 29; 40.3%), urinary tract infection (UTI) (n = 29; 40.3%) and vomiting (n = 11; 15.3%). The median age of presentation was 60 (36, 96) mo. Family history and consanguinity were present in 30 cases (41.7%) and 28 cases (38.9%) respectively. Stone analysis was done in 20 cases, of which 9 cases were mixed stones (predominant calcium oxalate) and 6 were calcium oxalate stones.

CONCLUSIONS

Among children with urolithiasis, hyperoxaluria, idiopathic hypercalciuria, idiopathic hyperuricosuria, and cystinuria were the predominant identifiable entities, together accounting for 72% of cases; and renal colic, hematuria and UTI were the commonest clinical complaints.

Evaluation of the composition of urinary tract stones in children from the Inner Western Anatolian Region in Turkey

OBJECTIVE

Pediatric urolithiasis is a globally growing problem. The composition and frequency of urinary tract stones vary not only among different countries, but across various regions in a country. Hence, we aimed to identify the types and frequencies of urinary tract stones in children from our region (Inner Western Anatolian part of Turkey), and to compare our findings with the results from other regions in our country.

MATERIAL AND METHODS

In this retrospective analysis of 53 pediatric urolithiasis cases that were treated in our hospital between 2009 and 2019, the demographic data, clinical course, radiological and metabolic findings, the recurrence rate, and the composition of the stones were evaluated.

RESULTS

The mean age of the patients was 5.9±4.6 (0.5-18) years, and there were 30 (56.6%) girls and 23 (43.4%) boys. An analysis of the composition of the stones revealed that the majority (85%) consisted of calcium oxalate. The highest risk of recurrence and the need for multiple shockwave lithotripsy (SWL) sessions or surgical intervention appeared to be related with the presence of whewellite stones, which are the most challenging stones in childhood.

CONCLUSION

According the study results, the urinary stone types vary across different regions in our country, and the frequency of uric acid stones decreased going westward, while the frequency of oxalate stones increased. We conclude that this difference in the frequency of the type of urinary stones might reflect the regional dietary habits. Regional frequency and etiology studies for the types of urolithiasis may facilitate the approach to the treatment of urolithiasis.

Prevalence of urolithiasis among the Uyghur children of China: a population-based cross-sectional study

OBJECTIVES

To investigate the prevalence and associated factors of urolithiasis amongst Uyghur children.

SUBJECTS AND METHODS

A cross-sectional survey was conducted of Uyghur children (aged ≤14 years) in the Kashgar Region of China, from July to December 2016. Children were selected by a two-stage random clustered sampling method, evaluated by urinary tract ultrasonography, low-dose computed tomography (CT) examination, blood and urine analysis, and a questionnaire. The prevalence by CT, the prevalence by self-report in the questionnaires, and the lifetime prevalence were evaluated. Binary logistic regression was used to estimate the associated factors.

RESULTS

A total of 5605 children were selected and invited to participate in the study. In all, 4813 Uyghur children (2471 boys and 2342 girls), with an mean (SD; range) age of 75.79 (43.81; 2-177) months, were included in the final analysis, with a response rate of 85.9%. The prevalence of paediatric urolithiasis was 1.8% (95% confidence interval [CI] 1.5-2.2) by CT, 2.3% (95% CI 1.9-2.7) by self-report, and 3.6% (95% CI 3.0-4.1) for the overall life-time. The age-sex adjusted prevalence was 2.0% (95% CI 1.6-2.4) by CT. Binary logistic regression analysis showed that body mass index, urinary tract infection, a family history of urolithiasis, and excessive sweating could increase the risk of stone formation, whilst breast feeding and drinking water at midnight could decrease the risk.

CONCLUSIONS

Urolithiasis is a major public health problem amongst Uyghur children, and strategies aimed at the prevention of urolithiasis are needed.

Multidimensional Analysis of Urinary Stone Diseases in Pediatric Patients

Objectives:

Urinary tract stones are less common in children than in adults. Determining the etiology is the most important step to achieve successful treatment and prevent future recurrence. The aim of this study was to investigate the clinical characteristics and possible risk factors for urinary stone disease in pediatric patients.

Methods:

The data of 126 patients with urinary stone disease who were treated in a pediatric nephrology clinic between 2000 and 2014 were analyzed retrospectively. A total 126 patients were enrolled in the study: 70 (55%) male and 56 (45%) female patients were included. The complaints, age of diagnosis, family histories, and stone location were examined. Direct urine microscopic examination, complete urinalysis, and urine culture were performed for all of the patients. Calcium, uric acid, oxalate, citrate, magnesium, and cystine levels were measured in urine collected in a 24-hour period. Serum electrolyte, blood urea nitrogen, creatinine, calcium, phosphorus, uric acid, and albumin levels were measured. Urinary ultrasound was performed. Stone analysis was conducted using the X-ray diffraction method. The mean age of the patients was 55 months (range: 1-162 months) at presentation.

Results:

In all, 34% of the patients had a family history of urinary stone disease. The rate of previous urinary tract infection was 26%. It was determined that 34% of the patients had been taking vitamin D and 5% had been taking a high dose. Metabolic risk factors determined were: hypercalciuria in 41%, hypocitraturia in 30%, hyperoxaluria in 14%, hyperuricosuria in 10%, and cystinuria in 5%. Among the group, 81% of the patients had kidney stones, 6.5% had ureter stones, and 2.5% had bladder stones. Furthermore, it was determined that 45% of the stones were composed of calcium oxalate, 35% had calcium phosphate stones, 14.2% had uric acid stones, and 13.3% had cystine stones. In 52% of the cases, extracorporeal shock wave lithotripsy was performed, and 71% underwent surgical treatment.

Conclusion:

Metabolic evaluation and stone analysis should be performed to prevent future recurrences in children with urinary stone disease and lifelong follow-up should be emphasized.

SWL outcome in artificial hydronephrotic vs. non-hydronephrotic kidney for preschool children with high-density renal stones

OBJECTIVE

To assess the effect of artificial hydronephrosis on the result of shock wave lithotripsy (SWL) in preschool children.

MATERIALS AND METHODS

A prospective randomized trial was performed between January 2013 and January 2017 with 300 pediatric patients, having kidney stones with a size of 1-2 cm and a density of 750-1100 HU. The patients were randomized into two groups: group A, in which a ureteric catheter was fixed and artificial hydronephrosis was performed by fluid irrigation prior to SWL, and group B which did not undergo hydronephrosis. SWL outcomes were compared between two groups.

RESULTS

In total, 153 cases were assigned to group A, and 147 cases were assigned to group B. Regarding demographic data, there was no statistically significant difference between the two groups. There were also no statistically significant differences in the number of shocks and energy power needed for each group. The results of SWL after the first session favored group A with a stone-free rate (SFR) of 90.8% vs. 75.5% for group B. The SFR after SWL was significantly in favor of group A (94.1%) vs. (86.4%) for group B.

CONCLUSION

The use of an artificial hydronephrosis technique to make interface around the stone improves stone-free rate and decreases the need for retreatment after SWL.

Stone growth patterns and risk for surgery among children presenting with hypercalciuria, hypocitraturia and cystinuria as underlying metabolic causes of urolithiasis

INTRODUCTION

Hypercalciuria, hypocitraturia and cystinuria are the most common underlying metabolic stone abnormalities in children. The present study compared stone growth patterns, stone burden, and the risk of stone-related surgery among these underlying metabolic conditions.

METHODS

A retrospective cohort of 356 children with renal stones, followed from 2000 to 2015, was studied. Differences among metabolic groups were determined using Kruskal-Wallis test; the Scheffé-test was used for multiple comparisons to determine differences among single groups. Independent sample t-test was used when adequate, given the sample size, and Chi-squared test was used for categorical variables. Stone growth rates were calculated as differences in diameter divided by time elapsed between U/Ss (mm/year). Logistic regression was performed to assess the effect of initial stone size on the likelihood of surgery.

RESULTS

Median stone size at presentation was significantly different among groups, with cystinuria being the group with the largest proportion of stones >10 mm, while patients with stones <5 mm were likely to have a normal metabolic workup (P < 0.05). Stones with a higher growth rate were found in the operative group, while slower growing stones were mostly managed conservatively (3.4 mm/year vs 0.8 mm/year, respectively; P = 0.014). However, stone growth rates were not significantly different among metabolic groups. On the other hand, the rate of new stone formation in cystinuric patients at their first follow-up was 30.4%, which was significantly higher than in patients with hypercalciuria (16.3%) or with a normal metabolic workup (17.2%; P < 0.05). Compared with stones <5 mm, stones measuring 5-10 mm were more than four times more likely to result in surgery, whereas the likelihood of surgery for 10-20 mm or >20 mm stones was almost 16 or 34 times, respectively (P < 0.001).

CONCLUSIONS

It is believed that this is the first study to evaluate stone growth patterns, stone burden and surgical risk among children with hypercalciuria, hypocitraturia and cystinuria. Cystinuric patients presented with larger stones at the time of diagnosis, higher new stone formation rates, and were at higher risk of surgery. While no significant difference of growth rate was found among metabolic groups, stones with a higher growth rate were significantly more likely to result in surgical treatment than slower growing stones. Initial stone size, location of largest stone, previous urinary tract infection, and patient's metabolic type significantly influenced the likelihood of a surgical intervention. Better understanding of the natural history ultimately helps surgeons and clinicians defining prognosis, treatment, and prevention plans for pediatric urolithiasis.

Bilateral hydronephrosis due to obstructive ureteral stone associated with norovirus gastroenteritis

Recently, cases of urinary tract calculi causing hydronephrosis and postrenal renal failure associated with viral gastroenteritis were documented, yet few were related to norovirus. During norovirus gastroenteritis, observation of oliguria, aciduria, low FENa value, and elevation of blood or urinary uric acid level may necessitate clinical workout for nephrolithiasis.

Epidemiology of paediatric renal stone disease: a 22-year single centre experience in the UK

Background

Whilst still rare, the incidence of paediatric stone disease is increasing in developed countries and it is important to evaluate the aetiology. We set up a dedicated renal stone service for children combining medical and surgical expertise in 1993 and now have a large case series of children to investigate the epidemiology.

Methods

A retrospective hospital note review of children presenting with kidney stones during the last 22 years (1993–2015) was conducted. All patients had a comprehensive infective and metabolic screen and were classified as metabolic, infective or idiopathic stone disease.

Results

Five hundred eleven patients (322 male) were reviewed. The median age of presentation was 4.4y for males (1 m-16.6y) and 7.3y (1–18.5y) for females with a median height and weight on the 25th centile for male and on 10th and 25th for female, respectively. One hundred seventy five (34%) had an underlying metabolic abnormality, 112 (22%) had infective stones and 224 (44%) were classified as idiopathic.

Of the 175 patients with a metabolic abnormality: 91 (52%) had hypercalciuria (76 persistent and 15 transient), 37 (21%) hyperoxaluria, 38 (22%) cystinuria, 3 (2%) abnormalities in the purine metabolism and the remainder other metabolic abnormalities. Bilateral stones occurred in 27% of the metabolic group compared to 16% in the non-metabolic group (OR 0.2, p < 0.05). Urinary tract infection was a common complication (27%) in the metabolic group.

Conclusions

In this paper, we present the largest cohort of paediatric stone disease reported from a developed country giving details on both, clinical and laboratory data. We show that in the majority of the patients there is an identifiable underlying metabolic and/or infective aetiology emphasizing the importance of a full work up to provide adequate treatment and prevent recurrence. Moreover, we show that stone disease in children, in contrast to the adult population, does not seem to be associated with obesity, as children have a weight below average at presentation.

Metabolic disturbances in Chinese children with urolithiasis: a single center report

Urinary stones and urine composition are the first steps in the process of recurrence prevention, but data concerning the association between the two compositions are scarce in Chinese children with urolithiasis. We retrospectively analyzed the records of children (age range 0-18 years) with urolithiasis in our center between March 2004 and December 2013. Stone analysis was carried out in 382 children and 24-hour urine analysis in 80 children. Analysis of both stone and 24-hour urine composition was completed in 56 children. Stone samples were analyzed by Fourier transform-infrared spectrometry. The major stone constituents were calcium oxalate (78.8 %). Of 80 children with 24 h urine analysis, only 2.5 % were without urinary metabolic abnormalities. Hypocitraturia was recorded in 97.5 %, high sodium excretion in 50.0 %, cystinuria in 48.7 %, hypercalciuria in 18.8 %, small urine volumes in 12.5 %, hyperoxaluria in 5.0 % and hyperuricosuria in 1.3 %. Interestingly, higher urine volumes were recorded in girls than in boys (73.2 ± 58.5 vs 51.3 ± 45.3 mL/kg, p = 0.036). Urine sodium (p = 0.002) and oxalate (p = 0.004) were significantly higher in children >9 year old. Moreover, compared with calcium oxalate stone formers, the urine volume (p = 0.040), citrate (p = 0.007) and cystine (p = 0.004) were higher in patients with cystine stones. Hypocitraturia was the common abnormality among Chinese children with urolithiasis. The surprisingly high incidence of cystinuria is of note.

Does obesity or hyperuricemia influence lithogenic risk profile in children with urolithiasis?

BACKGROUND

There are indications that obesity and hyperuricemia may influence the formation and composition of urinary stones. The aim of our study was to determine the effect of obesity and hyperuricemia on the urinary lithogenic risk profile in a large cohort of pediatric patients.

METHODS

The study population comprised 478 children with urolithiasis and 517 healthy children (reference group). We studied the effects of obesity on the lithogenic profile by dividing the patients with urolithiasis into two groups based on body mass index Z-score (patients who were overweight/obese vs. those with normal weight for age) and comparing the two groups. To study the effect of hyperuricemia on the lithogenic profile, we divided the patients with urolithiasis into two groups based on the presence or not of hyperuricemia (110 patients with urolithiasis accompanied by hyperuricemia vs. 368 patients with urolithiasis and normal serum uric acid levels) and compared the groups.

RESULTS

Among the children and adolescents with urolithiasis and hyperuricemia, there was a significantly lower excretion of crystallization inhibitors (citrates, magnesium). We also found significantly negative correlations between serum uric acid levels and the urine citrate/creatinine ratio (citrate/cr.; r = -0.30, p < 0.01), as well as the magnesium/cr. ratio (Mg/cr.; r = -0.33, p < 0.01). There was no statistically significant differences in the urinary excretion of oxalates, citrates, calcium, phosphorus, magnesium and uric acid between children with urolithiasis who were either overweight or obese and children with urolithiasis who had a normal body weight.

CONCLUSIONS

In our pediatric patient cohort, hyperuricemia was associated with a decrease in the excretion of crystallization inhibitors in the urine, but the clinical relevance of this observation needs to be confirmed in future studies. Obesity and overweight had no direct influence on the lithogenic risk profile in the urinary stone formers in our study, but there was an indication that higher serum uric acid may be associated with impairment in renal function, which in turn could influence the excretion of lithogenic parameters.

High incidence of urinary stones in Uyghur children may be related to local environmental factors

OBJECTIVE

To analyze the causes of urolithiasis in Uyghur children from Xinjiang.

PATIENTS AND METHODS

We retrospectively evaluated the clinical features and characteristics of urinary stone composition of 220 Uyghur pediatric patients with urolithiasis between March 2009 and June 2011. The data were compared with that of 100 Uyghur children without urolithiasis who visited the Child Care Clinic for regular health check-ups. The stones were collected by endoscopy or open surgery, and analyzed using infrared spectroscopy.

RESULTS

The mean age of the 220 Uyghur children was 7.48 ± 4.73 years (range, 0.8-17.0 years). The overall sex ratio (male:female) was 2.23:1. The predominant pure stone was ammonium urate (58.9%), whereas the predominant mixed stone was calcium oxalate mixture (91.1%). Uric acid stones comprised 54% of all stones. Urinary tract infections were observed in 42.3% and 4.0% of the patient and control groups, respectively. The mean urinary pH values were 5.77 ± 0.67 and 6.42 ± 0.67, respectively (p < 0.001). pH values were <5.5 in 52.7% and 6% of the patient and control groups, respectively. On 24-h urine analysis, we found metabolic disturbances in these patients: hypercalciuria in 6.8% cases, hyperphosphaturia in 16.8% cases, hyperuricosuria in 21.4% cases, and hypomagnesiuria in 34.1% cases.

CONCLUSIONS

Urolithiasis in Uyghur children may be primarily related to local environmental factors.

Clinical importance of renal calyceal microlithiasis in children

BACKGROUND

Renal calyceal microlithiasis refers to a hyperechogenic spot in renal calyces <3 mm in diameter detected on renal sonography. These spots possibly represent the first step in calculus formation. The aim of this study was to analyze the clinical presentation, predisposing factors, prognosis and clinical importance of these hyperechogenic spots in renal calyces, renal calyceal microlithiasis, during childhood.

METHODS

The data of 292 children (135 girls, 157 boys) with microlithiasis diagnosed between January 1998 and December 2010 were evaluated retrospectively. Demographic data, serum biochemistry, urinary metabolic factors, and renal sonography results were obtained from patient files. A total of 228 patients were re-evaluated at least 6 months after the first observation of renal calyceal microlithiasis and at 6-12 month intervals thereafter.

RESULTS

Mean age was 16.8 ± 14.9 months, and mean follow-up duration was 14.6 ± 5.9 months. Presenting symptoms were abdominal or flank pain (41.1%), hematuria (35.6%), dysuria (24.7%) and urinary tract infection (34.6%). Previous ultrasounds were normal in 35% of the children. Metabolic and anatomic abnormalities were found in 55.5% and 17.8%, respectively. Hypercalciuria was the most common metabolic abnormality (88.9%). Among 228 patients who had been re-evaluated, microlithiasis disappeared in 37.7%; decreased in number or size in 23.7%; progressed to renal stone formation in 10.6%; increased in number of microlithiasis in 19.0%; and remained unchanged on radiology in 9.0%.

CONCLUSION

Renal calyceal microlithiasis represents a spectrum of clinical situations and underlying metabolic abnormalities that need further investigation in children.

Pediatric urolithiasis: experience from a tertiary referral center

OBJECTIVE

Pediatric urolithiasis can cause significant morbidity and damage to the kidney, or even renal failure. We review our experience of the management of urolithiasis in pediatric patients at a tertiary referral center.

PATIENTS AND METHODS

We reviewed medical records of all children with urolithiasis who were diagnosed and managed at our center from August 2003 to October 2011. Management was planned according to stone burden and location. We noted and statistically analysed data about age, sex, stone burden, clinical features, management, metabolic abnormalities and recurrence.

RESULTS

There were 325 children with 378 stone sites. Age range was 3-17 (mean 8) years. The male to female ratio was 3:1. Most common presentation was abdominal pain in 257 children (79%), and the most common stone site was kidney in 215 (57%). Twenty-four (7%) children (stone burden ≤3 mm) were managed conservatively, while the rest received some form of intervention. Metabolic workup could be done in 154 (47%) children. A metabolic abnormality was seen in 67 (43%) children, normocalcemic hypercalciuria being the most common. Recurrence of urolithiasis was seen in 78 (24%) children after a mean follow-up of 3.2 (1-6) years, and was more common in those who had a metabolic abnormality or in whom small residual fragments were left in situ.

CONCLUSIONS

Availability of smaller instruments has led to safer use of percutaneous endoscopy and ureteroscopy in children, with results comparable to those in adults and an acceptable complication rate. The presence of a metabolic abnormality is quite common and is a cause of recurrence.

Diagnosis and therapy of acute urolithiasis caused by melamine contamination in infant formula milk

The aim of this study was to determine the clinical characteristics and diagnosis of severe, acute urolithiasis in infants and toddlers, caused by melamine contamination in infant formula milk. The clinical data of 28 patients were collected and analyzed. Among the 28 patients, 17 patients received indwelling ureteral stents by cystoscopy (60.71%) and 5 patients received open surgery to extract calculi (17.86%). Four patients received catheterization or diuretic, anti-inflammatory or antispasmodic treatment (14.28%). Two patients underwent a second open surgery to extract calculi (7.14%). Eventually, the stones were eliminated from 23 patients and 5 patients had residual stones. In the 5 patients with residual stones, 3 patients had kidney stones, hydronephrosis or unilateral ureteral stones, resulting in urinary obstruction following surgery. Urolithiasis in infants and toddlers caused by melamine contamination was diagnosed, with common symptoms, including acute anuria, oliguria and dysurias. Ultrasonic inspection may be used to successfully examine urinary stones. Computed tomography (CT) scanning further detects the position of the stones and the degree of edema. Ureteral stenting via cystoscopy is a useful method, resulting in minimal trauma and a positive prognosis.

Rise in emergency department visits of pediatric patients for renal colic from 1999 to 2008

OBJECTIVE

Renal colic has been considered predominantly a disease of adults with only occasional cases occurring in the pediatric population. A recent report from a single hospital showed a rise in the number of children with renal colic. Our objective was to examine this in a much larger multihospital database of emergency department (ED) visits.

METHODS

This study has a retrospective cohort design. It was conducted on consecutive pediatric patients (age <18 years) with a diagnosis of "renal colic, calculus kidney, calculus ureter, urinary calculus, or urethral calculus" according to the International Classification of Diseases, Ninth Revision, as seen by ED physicians in 29 urban, suburban, and rural EDs in New Jersey and New York between January 1, 1999, and December 31, 2008. We analyzed the number of renal colic visits as a percent of total ED pediatric visits in yearly intervals using the Student t test and performed a regression analysis. The α was set at 0.05.

RESULTS

The database contained 6,497,458 total ED visits, of which 1,312,487 (20%) were pediatric visits. Of these, 1005 (0.077%) were for renal colic. The median age of these pediatric patients was 16 years (interquartile range, 13-17 years) and 61% were female. The percentage of ED pediatric visits for renal colic increased from 0.048% in 1999 to 0.089% in 2008, an increase of 86% (95% confidence interval, 36%-154%; P < 0.001). The correlation coefficient for this upward trend was R2 = 0.69 (P = 0.003).

CONCLUSIONS

We found a marked increase in ED pediatric visits for renal colic over the past decade. This may reflect a real increase in the incidence of renal colic in the pediatric population or an increased use of imaging modalities for abdominal and flank pain.

Assessment of risk factors of pediatric urolithiasis in Egypt

OBJECTIVE

Pediatric urolithiasis is a significant medical problem, which has seen an increasing incidence in developing countries. The main objective of the present study was to investigate the clinical characteristics and the most important risk factors that contribute to stone formation in Egyptian children.

PATIENTS AND METHODS

This prospective study was carried out at the outpatient clinics of Cairo university children's hospital as well as October 6 University hospitals, between November 2008 and March 2012. One hundred and fifty children (100 males, 50 females; mean age 3.5 years; range, 1-14 years) suffering from urinary stones were included. The mean follow-up duration; 33.1 months. All patients underwent detailed medical and family histories, dietary habits and physical examination, including Growth percentiles. Laboratory investigations were performed including: complete urine analysis and culture and sensitivity tests, urine collection in 24-h to quantity urinary volume, pH, calcium, uric acid, magnesium, creatinine, oxalate and citrate. Blood samples were obtained to measure (serum creatinine, calcium, phosphorus, uric acid level, and alkaline phosphatase and electrolyte levels, in addition to pH and pCO2 values). Radio-sonographic investigation of the abdomen and pelvis was also performed.

RESULTS

The commonest presentations were abdominal pain in 42 children (28%) and gross hematuria in 35 patients (23%). Urinary tract infection was the most common risk factor, 60 patients (40%) had UTI, 70% of them had recurrent infections. Genito-urinary abnormalities, as a risk factor, were detected in 38 children (25%), with vesico-uretheral refux being the commonest abnormality (18/38). Metabolic risk factors were detected in 34 children (23%) with hypercalciuria and hyperoxaluria being the commonest metabolic abnormalities. Treatments used were, ESWL in 69 patients (46%), endoscopic interventions in 40 children (27%) and open surgery in 15 children (10%). The remaining 26 children (17%) were managed conservatively.

CONCLUSIONS

treatment of pediatric urolithiasis requires stone removal besides a thorough metabolic and environmental evaluation of all patients on an individual basis, entailing the treatment of metabolic abnormalities. Children with a positive family history should be followed up cautiously to avoid stone recurrence.

Pediatric primary urolithiasis: 12-year experience at a Midwestern Children's Hospital

PURPOSE

Due to environmental and social changes (and possibly obesity) as new risk factors for stone formation in adults and changes in imaging techniques, we assessed whether etiologies of primary pediatric urolithiasis have changed, and if relationships exist between the condition and obesity or imaging technique.

MATERIALS AND METHODS

All pediatric patients with documented primary urolithiasis who underwent serum and 24-hour urine analyses between 1999 and 2010 were evaluated. Age at diagnosis, gender, body mass index and imaging technique were recorded.

RESULTS

Of the 222 patients (48% male) all had normal serum creatinine, electrolytes and minerals. Primary pediatric urolithiasis was diagnosed by ultrasound in 73% of cases and computerized tomography in 27%. Mean ± SD annual incidence of urolithiasis per 1,000 clinic visits increased from 2.4 ± 1.5 in the first half of the study period to 6.2 ± 2.1 in the second half (p <0.005). Mean ± SD age at diagnosis was 11.8 ± 3.8 years and body mass index was 21.7 ± 5.7 (rate of overweight 15%). A total of 140 patients had urine output less than 1.0 ml/kg per hour, with this being the only abnormality in 54. Hypercalciuria was observed in 46% of patients, hypocitraturia in 10% and high calcium-to-citrate ratio in 51%. Mild absorptive hyperoxaluria was noted in 3 patients and hyperuricosuria in 11, with all 14 exhibiting at least 1 additional abnormality. Cystinuria was present in 1 patient. No etiology was identified in 20 patients (9.0%).

CONCLUSIONS

Oliguria and hypercalciuria continue to be the most common etiologies of pediatric primary urolithiasis, followed by hypocitraturia. The recent increase in stone incidence is unlikely due to increased use of computerized tomography. Incidence of obesity was not higher than in the general population. Hyperoxaluria and cystinuria are rare, and thus might not be indicated in the initial analysis.

Pediatric urolithiasis: causative factors, diagnosis and medical management

Childhood urolithiasis is associated with considerable morbidity and recurrence. Many risk factors--including those metabolic, genetic, anatomic, dietary and environmental in nature--have been identified in children with urinary tract calculi. As pediatric urolithiasis with a metabolic etiology is the most common disease, evaluating the metabolic risk factors in patients is necessary to both effectively treat current stones and prevent recurrence. We discuss causative risk factors of pediatric urolithiasis, as well as the diagnostic and therapeutic approaches.

Urolithiasis in infants: evaluation of risk factors

OBJECTIVE

Urolithiasis in infants is not a very rare situation in Turkey, and the incidence has been increasing in recent years. The purpose of this paper was to investigate the clinical characteristics, metabolic and anatomic risk factors for urolithiasis and microlithiasis in infants.

METHODS

The cases of 178 infants (63 girls, 115 boys), who were referred to our department between 1999 and 2009 with urolithiasis, were evaluated.

RESULTS

The mean age at diagnosis of stone disease was 11.5 months (range, 10 days-24 months). The mean follow-up duration was 33.6 months (1.2-110 months). The major clinical symptoms of our patients were restlessness in 24 children (13.5%) and vomiting in 23 (13%). Thirty-five infants (19.7%) had a urinary tract abnormality; vesico-ureteral reflux was the most common abnormality (12.9%). Hypercalciuria and hyperuricosuria were detected in 46 and 56%, respectively. Stone analysis was performed in 56 infants, and calcium oxalate was determined in 36 patients (64.3%). A family history of urolithiasis, presenting symptoms and underlying metabolic abnormalities were similar for patients with microlithiasis and those with larger stones. However, infants with microlithiasis had higher ratios for history of vitamin D administration and feeding with formula. Surgical treatment was performed in 42 infants and extracorporeal shock wave lithotripsy in 30 infants.

CONCLUSION

Our results showed that urolithiasis in infants may present nonspecific symptoms and may even be asymptomatic and that a positive family history for urolithiasis, urologic abnormalities, metabolic disorders, urinary tract infections, vitamin D administration and feeding with formula may increase the occurrence of urolithiasis in infants.

Evaluation of children with urolithiasis

Objectives:

To describe an evaluation protocol for pediatric stone formers for risk assessment and management strategies.

Materials and Methods:

Between 2002-2006, 2618 children of age three months to 15 years were evaluated for stone disease. Evaluation included demographics, history, anthropometry, diet, ultrasound, X-ray KUB, IVU, blood and 24h urine chemistry and cultures. Stones were analyzed by IR spectroscopy.

Results:

The median age was seven years with a M:F ratio of 2.2:1. Of the 2618 patients, 2216 presented with normal renal function and 402 with renal failure. Main symptoms were abdominal pain (33%), flank pain (38%) and fever (38%). Renal failure patients also had shortness of breath (38%) and oligo-anuria (26%). Children were malnourished with height and weight deficits in 65% and 76% respectively. Diet was low in protein (74%), calcium (55%) and fluids in (55%), high in oxalate (55%), sodium (39%), purines (42%) and refined sugar (41%). Overall urine cultures were positive in 1208 (46%) with E. coli (38%) and Klebsiella (8%).

Stone distribution was renal in 64%, ureter in 8%, bladder in 18%, bilateral in 40% and multiple sites in 18%. Median stone size was >1.5-2.0 cm. The frequency of compounds in stones was ammonium urate (58%), calcium oxalate (63%), uric acid (6%), calcium phosphate (12%) and struvite (8%). Metabolic abnormalities included hypovolumia (31%), hypocitraturia (87%), hyperoxaluria (43%) and hyperuricosuria (26%). Dietary and medical treatment corrected risk factors in two-thirds of patients with a recurrence rate of about 1.15%.

Conclusion:

An evaluation based on history, imaging, diet, metabolic analysis and stone type can help to tailor management strategies.

Epidemiology of pediatric urolithiasis

Pediatric urolithiasis has increased globally in the last few decades. There has been a change in the pattern of stone composition with an increase in the frequency of kidney stones and a decrease in bladder stones. The role of familial predisposition and environmental factors in pediatric urolithiasis is now better understood. Metabolic factors are more common in pediatric urolithiasis than in adult stone disease. This review updates on the epidemiology of pediatric urolithiasis with a focus on the changing trends in the stone disease, current spectrum of stone disease encountered in clinical practice, individual predisposition and the role of environmental factors in stone formation.

Pediatric urolithiasis: experience at a tertiary care pediatric hospital

OBJECTIVE

We aimed to determine the epidemiology, risk factors, clinical characteristics, evaluation and course of patients with urolithiasis at the Children's Hospital of Eastern Ontario to improve current diagnostic and management strategies.

METHODS

This was a retrospective study of children with newly identified urolithiasis between Jan. 1, 1999, and July 31, 2004. Cases were reviewed for demographics, presentation, family history, diagnostic methods and findings, metabolic and anatomic abnormalities, management, stone analysis and stone recurrence.

RESULTS

Seventy-two patients (40 male, 32 female; mean age 11.3 yr) were assessed. Mean follow-up was at 1.5 years. Eighteen patients (25%) had a family history of stones. Flank pain (63%) was the most common presentation. Eighty-two percent of urinalyses showed microscopic hematuria. Imaging comprised abdominal plain film radiography (56%) and (or) abdominal ultrasonography (74%). The mean stone size was 5 mm. Forty-one percent (28/69) of patients who underwent metabolic investigation had an abnormality. Fourteen percent of patients (10/72) had a genitourinary anatomical abnormality. Thirty-four patients (47%) passed their stones spontaneously, 25 patients (35%) required surgical intervention and 13 patients (18%) had yet to pass their stone. The mean size of spontaneously passed stones was 4 mm. Of 42 stones analyzed, 39 (93%) were composed of calcium oxalate or phosphate. Seventeen (24%) patients had stone recurrence during follow-up.

CONCLUSION

Pediatric patients with stones present in a manner similar to adults. Abdominal plain film radiography and ultrasonography are the preferred initial radiological investigations in children as they limit radiation exposure. Metabolic abnormalities are common and may coexist with anatomic abnormalities, therefore investigations must rule these out. One-half of patients will pass their stones spontaneously. Recurrence rates are high and long-term follow-up is recommended.

Infrared spectroscopic analysis of urinary stones (including stones induced by melamine-contaminated milk powder) in 189 Chinese children

AIM

The aim of the study was to investigate the composition of the stones in Chinese children with urolithiasis, including peculiar stones induced by melamine-contaminated milk powder.

MATERIALS AND METHODS

Between 1999 and 2009, 189 urinary stones from children of East China were received at our institution. Among them, 12 stones were received from pediatric stone formers with a history of consuming melamine-contaminated milk powder in 2008; and the remaining stones were defined as "natural" stones. All stones were analyzed by Fourier transform infrared spectroscopy.

RESULTS

Among 177 "natural" stones, whewellite stone (49.72%) was observed most frequently followed by weddellite stone (15.25%), uric acid anhydrous stone (9.6%), carbapatite stone (9.04%), cystine stone (9.04%), ammonium acid urate stone (4.52%), struvite stone (2.26%), and sodium urate stone (0.56%). Twelve young children who consumed melamine-contaminated milk powder were younger than 3 years, and their stones were composed of a mixture of uric acid dihydrate and ammonium acid urate based on Fourier transform infrared spectroscopy. In addition, the stones were radiolucent and could be dissolved by urine alkalinization.

CONCLUSIONS

Our study emphasizes the relatively high rate of calcium oxalate stones and cystine stones, and the relatively low rate of struvite stones in Chinese children with urolithiasis. The stones caused by melamine-contaminated milk powder are composed of the mixture of uric acid dihydrate and ammonium acid urate.

Urolithiasis in the first year of life

Data on urolithiasis (UL) in infancy are limited. The objective of this study was to increase awareness of infant UL and to investigate the influence of possible risk factors in this very specific age group. Nonfasting, second-voiding urine samples were obtained to test for urinary excretions of calcium, oxalate, citrate, magnesium, uric acid, and creatinine. Blood analysis included calcium, phosphate, magnesium, uric acid, creatinine, sodium, potassium, chloride, and alkaline phosphatase. Patients received follow-up testing every 1-2 months; serial ultrasonography was used to track UL status. Fifty infants with a median age of 5 months were enrolled in the study. Hypercalciuria was detected in 9/47, hyperoxaluria in 5/39, hypocitraturia in 4/31, and cystinuria in 2/50 infants. We identified at least one metabolic abnormality in 46% of our patients; no metabolic abnormality was identified in 27 infants. Within a mean follow-up period of 14 months, 17 infants became stone free, stones increased in number in ten patients and decreased in number in 16, and recurrence was detected in seven. This study showed that UL could be detected in very early life, even in the newborn period, and could be the source of late childhood/adulthood UL. Infants with nonspecific symptoms such as restlessness may have UL and should undergo ultrasonographic examination. Metabolic evaluation of UL in this specific age group carries some diagnostic challenges, e.g. unsatisfactory data regarding normal ranges of urinary mineral excretion, and collection of 24-h urine samples.

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.

Sex prevalence of pediatric kidney stone disease in the United States: an epidemiologic investigation

OBJECTIVES

To define the sex prevalence of inpatient hospital discharges for pediatric patients diagnosed with upper urinary tract stone disease.

METHODS

The study examined inpatient admissions for pediatric urolithiasis in 2003, using the Healthcare Cost and Utilization Project Kids' Inpatient Database. We used the International Classification of Disease, 9th edition, Clinical Modification codes, to identify patients with a principal diagnosis of renal (592.0) or ureteral (592.1) calculi. Sex prevalence was assessed, and the results were stratified by age group.

RESULTS

In the 2003 Kids' Inpatient Database, the sex distribution among pediatric patients with stone formation varied significantly by age. In the first decade of age, a male predominance was found that had shifted to a female predominance in the second decade. Overall, however, girls in the pediatric population were more commonly affected by stones than were boys.

CONCLUSIONS

In this nationally representative sample, the sex distribution of pediatric urolithiasis varied with age, with boys more commonly affected in the first decade of age and girls in the second decade. Although the reason for this unique epidemiologic finding is not readily apparent, additional studies can build on this hypothesis-generating work.

The metabolic etiology of urolithiasis in Turkish children

Pediatric urolithiasis is an endemic disease, especially in certain developing regions of the world, such as the Far East, and to a certain extent the Middle East and Turkey. The aim of the study is to determine the metabolic etiology and the prevalence of formation of urinary calculi in Turkish pediatric patients with urolithiasis. Seventy-two pediatric patients diagnosed as having urolithiasis were studied from 1999-2005 in Dr. Behcet Uz Child Disease and Surgery Education and Research Hospital Nephrology Department, Izmir, according to their presenting signs and clinical and laboratory findings. The other necessary tests were also applied to detect the etiology of the calculi formation. Of the 72 patients, 50 (69.4%) were male and 22 (30.6%) were female, with ages ranging from 2 to 168 months (mean age 72 +/- 35.7 months), and the male-to-female ratio of patients was 2.3. Twenty-four (33%) of them were diagnosed as having metabolic urolithiasis, 21 (30%) anatomic, 19 (26%) infectious and 8 (11%) idiopathic. The age at which urolithiasis was first diagnosed was found to be low in the metabolic and anatomic etiology groups (P = 0.028). Thirteen patients (18%) with urolithiasis were known to have a family history of stone disease, and in all of them metabolic etiology was considered to be the reason (P < 0.001). In all of the groups, the localization of the stone was found to be the upper urinary system most of the time, and in 17 (24%) with bilateral multiple stones, the etiology was found to be metabolic (P < 0.001). All of the patients were followed up for 3-72 months (mean 29.2 +/- 13.7 months), and four of them (5.5%) had recurrences. In order to prevent renal damage and recurrences in pediatric patients with urolithiasis in Turkey in whom the etiology is mostly metabolic, the illnesses must be investigated very cautiously, and their early diagnosis and treatment modalities must be considered.

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.

Reference values of plasma oxalate in children and adolescents

Oxalate homeostasis is a derivative of absorption and transportation in the digestive system and renal/intestinal excretion of oxalate. The objective of this cross-sectional study was to determine normative values of plasma oxalate in relation to age, gender, and body size. A group of 1,260 healthy Caucasian children and adolescents aged 3 months to 18 years [mean +/- standard deviation (SD) 10.5 +/- 4.3] was studied. Each 1-year group comprised 70 subjects. Oxalate levels were assessed in blood plasma samples obtained from fasted individuals using the precipitation-enzymatic method with oxalate oxidase. Median oxalate levels in healthy infants was 3.20 micromol/L (5th-95th percentiles: 1.56-5.58) and was higher compared with older children [2.50 micromol/L (5th-95th percentiles: 0.95-5.74); p < 0.01]. No differences were found in plasma oxalate levels between boys and girls. There were no associations between plasma oxalate levels and anthropometric traits. In the healthy population aged 1-18 years, plasma oxalate concentration is independent of age, gender, and body size. Infants demonstrate higher plasma oxalate levels compared with older children, which suggests possible immature mechanisms of renal excretion. This study appears to be the first extensive report providing normative data for plasma oxalate in children and adolescents.

A boy with a large bladder stone

Despite the frequent association of urinary tract infection with vesicoureteral reflux and urinary calculi, since vesicouretal reflux is induced by bladder stones, the coexistence of vesicoureteral reflux and bladder stones is rare. Because of its occurrence in children belonging to poor socioeconomic groups, it is believed to be a deficiency disorder. Most cases of bladder stones occur between the ages of 2 and 5 years. Common clinical presentations of bladder stones include urinary dribbling and enuresis, frequency of micturition, pain during micturition, pelvic pain and hematuria. We report the occurrence of a large bladder stone in a boy, who experienced intermittent Lower abdominal pain and urinary incontinence, both during the day and at night. He had been diagnosed with enuresis and treated in pediatric clinics for 1 year. Delayed diagnosis resulted in bladder stone formation. The stone was larger than 2.5cm and open vesicolithotomy was therefore selected as the best and safest treatment choice. His symptoms disappeared after surgery. Thorough metabolic and environmental evaluations of such cases are required on an individual basis. Bladder stones should be considered as a possible diagnosis in children presenting with urinary incontinence.

Xanthinuria type I: a rare cause of urolithiasis

Xanthinuria type I is a rare disorder of purine metabolism caused by xanthine oxidoreductase or dehydrogenase (XDH) deficiency. We report a family with two affected children out of 335 pediatric stone patients studied since 1991 in Armenia. The propositus, a 13-month-old boy, presented with abdominal pain and urinary retention followed by stone passage (0.9x0.6 cm). Infrared spectroscopy in Yerevan revealed a pure xanthine stone. Family examination in the parents and brother was normal, but the propositus and his 8-year-old asymptomatic sister had hypouricemia, hypouricosuria, and high urinary excretion of hypoxanthine and xanthine. Ultrasonography in the index patient showed bilateral stones requiring pyelolithotomy. High fluid intake and purine restriction did not prevent further stone passages. The affected asymptomatic sister had a small pelvic stone (4 mm). Mutation analysis revealed a heterozygous novel base pair substitution in exon 25 of the XDH gene (c.2810C>T), resulting in an amino acid substitution (p.Thr910Met). The second mutation could not be detected. Despite this, the heterozygous mutation, the chemical findings, and the positive allopurinol test altogether prove xanthinuria type I, which may present wide clinical intrafamilial variation. Diagnosis is suspected usually from low serum uric acid. No specific therapy is available.

Medical evaluation and treatment of urolithiasis

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

Aetiological factors in paediatric urolithiasis

The aetiology of stones in children differs from that in adults. Young children, especially boys, are prone to infective stones, although this type of calculi is decreasing in frequency over time in prosperous countries. Two monogenic causes, cystinuria and hyperoxaluria, each account for 5-15% of paediatric stones. Increased factors for stone formation in children include prematurity, neurological problems, ketogenic diet and reconstructed or augmented bladders. Hypercalciuria is commonly found in paediatric stone formers, is usually idiopathic and is only rarely associated with hypercalcaemia. All children with stones should undergo a metabolic evaluation.

Etiological and clinical patterns of childhood urolithiasis in Iraq

This study was conducted to evaluate the etiological and clinical characteristics of urolithiasis in Iraqi children. From 1999 to 2004, 204 children with renal calculi were evaluated. The age range of the patients was 4 months to 14 years, 61.3% of the patients were under 5 years. Male to female ratio was 2.8:1. The mean age at onset of symptoms was 3.2 years, and stone disease was diagnosed at a mean of 3.5 years. Hematuria (44.6%) and pain (28.4%) were the main clinical presentation. Of the 204 patients 45.1% had a family history of stones. Consanguinity was recorded in 72%; 75.5% had metabolic disorders. Stones were located at multiple sites in 80 patients, or 39.2%; 58 of these 80, or 72.5%, had metabolic disorders. Multiple stones were present in 47 (23%); 72.3% were related to metabolic disorders. In 126 patients, or 61.8%, both kidneys were involved equally. Bladder stones were found in 11.3%. Staghorn calculi occurred in 29 patients, or 14.2%; 27 of these had recurrent urinary tract infection (UTI). Nephrocalcinosis was diagnosed in 7, or 3.4%; all had metabolic disorders. Etiology of stone formation was established in 189 patients, or 92.6%, whereas 15, or 7.4%, had idiopathic stones. Metabolic disorders were the commonest cause in 106 patients (52%); 52 patients were classified as infective (25.5%). Anatomical defects were present in 25 (12.2%) and 6 children (2.9%) with primary endemic bladder calculi. Coexisting UTI was common (36.8%) in the metabolic group. We concluded that urolithiasis is a serious problem among Iraqi children, with early onset of presentation. Metabolic disorders were the major causes, but can be masked by associated UTI. Proper management of UTI with a careful metabolic assessment of young stone formers is valuable in combating urolithiasis.

Percutaneous nephrolithotomy in children: experience with 138 cases in a developing country

Our aim was to evaluate our experience with percutaneous nephrolithotomy (PCNL) in children in the Republic of Yemen. Between January 1993 and December 1998, 135 children underwent 138 percutaneous nephrolithotomies in Yemen. The patient's age ranged between 8 months and 14 years (average 8.9 years). There were 117 boys and 18 girls (male:female ratio 6.5:1). The stone size ranged between 124 and 624 mm2 (average 507 mm2). A 26 F adult nephroscope was used. The stone free rate was 98.5% (136 out of the 138 cases). Two patients had clinically insignificant fragments. A second session had to be performed because of residual stone in one patient. No severe intra- or postoperative complications were observed. We conclude that percutaneous nephrolithotomy is a safe and effective method for the treatment of kidney stones in children. It reduces morbidity and hospital stay and thus the cost of treatment. To our knowledge, this is the largest reported series.

Endoscopic management of pediatric urolithiasis in a developing country

OBJECTIVES

To evaluate our experience with the endoscopic management of lower and upper urinary tract stones in pediatric patients in the Republic of Yemen.

METHODS

From January 1, 1993 to December 31, 1998, 290 endoscopic operations were performed on 265 pediatric patients up to 14 years of age, 173 on the upper and 117 on the lower urinary tract. Of these procedures, 138 were percutaneous nephrolithotomy, 5 were endopyelotomy combined with percutaneous nephrolithotomy, 30 were ureteral lithotripsy, and 117 were percutaneous cystolithotomy. Of the 265 patients, 244 were boys and 21 girls (male/female ratio 11.6:1, upper tract 7.4:1, lower tract 116:1) aged 8 months to 14 years (mean age 7.1 years). The 26F adult nephroscope and 9.5F semirigid ureteroscope were used.

RESULTS

The overall success rate was 98.9%. Minor complications were observed in 29 patients (10.7%); severe complication did not occur. The nucleus and/or the main component of the stones was ammonium urate in 73.5% of the cases (upper tract 54%, but for those younger than 5 years, it was 75%; lower tract 93%).

CONCLUSIONS

The endoscopic management of pediatric urolithiasis is a safe and effective method. To our knowledge, this is the largest reported series on the endoscopic management of pediatric urolithiasis.

Epidemiology of paediatric renal stone disease in the UK

BACKGROUND

The previous epidemiological study of paediatric nephrolithiasis in Britain was conducted more than 30 years ago.

AIMS

To examine the presenting features, predisposing factors, and treatment strategies used in paediatric stones presenting to a British centre over the past five years.

METHODS

A total of 121 children presented with a urinary tract renal stone, to one adult and one paediatric centre, over a five year period (1997-2001). All children were reviewed in a dedicated stone clinic and had a full infective and metabolic stone investigative work up. Treatment was assessed by retrospective hospital note review.

RESULTS

A metabolic abnormality was found in 44% of children, 30% were classified as infective, and 26% idiopathic. Bilateral stones on presentation occurred in 26% of the metabolic group compared to 12% in the infective/idiopathic group (odds ratio 2.7, 95% CI 1.03 to 7.02). Coexisting urinary tract infection was common (49%) in the metabolic group. Surgically, minimally invasive techniques (lithotripsy, percutaneous nephrolithotomy, and endoscopy) were used in 68% of patients.

CONCLUSIONS

There has been a shift in the epidemiology of paediatric renal stone disease in the UK over the past 30 years. Underlying metabolic causes are now the most common but can be masked by coexisting urinary tract infection. Treatment has progressed, especially surgically, with sophisticated minimally invasive techniques now employed. All children with renal stones should have a metabolic screen.

Extracorporeal shock-wave lithotripsy for treatment of ureteral calculi in paediatric patients

Our objective was to determine the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of paediatric ureteral calculous disease. We reviewed the records of 41 (23 boys, 18 girls) paediatric patients admitted to our clinic for the treatment of ureteral calculi between between 1989-2001. Patients' age varied between 4-16 years. The majority of the patients, 38 (92.7%) cases were treated initially with ESWL whereas 3 (7.3%) cases were subjected to ureterolithotomy. The mean age of the patients was found as 12.8+/-3.86 (4-16) years. Most calculi were located at either upper or lower ureter. The mean stone burden was 45.16+/-30.65 mm2 and the mean shock wave number per session and power as 2826.72+/-605.18 and 17.69+/-1.11 kV respectively. Minor complications included skin ecchymosis at the site of entry of shock waves in all cases and renal colic that responded to analgesics and emetics in 3 (7.9%) patients. The overall stone-free rate after ESWL was found to be 81.6%. Two (5.3%) cases have residual fragments that escaped to lower calices after lithotripsy for upper ureteral calculi and are still followed. There were 5 (13.2%) failures who were treated with ureterolitotomy for 1 upper and 1 lower ureteral calculi and with ureteroscopy for the rest. It appears that ESWL is still a good option for the initial treatment of most ureteral calculi in children as it is less invasive than ureteroscopy and has a high success rate as a first-line therapy.

Urinary analysis of nephrolithiasis markers

Renal stone disease is an ancient and common affliction, common in industrialised nations. The causes and incidence of nephrolithiasis are presented. Afterwards, the promoters and inhibitors of renal stone formation analysis in urine are described including enzymatic methods, chromatography, capillary electrophoresis and other techniques. Aspects such as sample collection and storage are also included. The review article includes referenced tables that provide summaries of methodology for the analysis of nephrolithiasis related compounds.