Risk factors for nephrolithiasis in children

Pathways to paediatric urology subspecialisation: a study of casemix, incumbent attitudes and opinions

OBJECTIVE

To identify any self-reported differences or attitudes towards certification, publication, or practice patterns between adult urology and paediatric general surgery-trained paediatric urology providers. There are no known published differences in clinical/operative/research outcomes in either group.

METHODS

An 18-item cross-sectional survey was compiled through the EAU Young Academic Urologists (YAU) office and disseminated to a trans-Atlantic convenience sample of current practising paediatric urologists. This was created using a mini-Delphi method to provide current semi-quantitative data relating to current opinions and attitudes of this cohort.

RESULTS

A total of 228 respondents completed the survey, with female respondents representing 37% and 34% for urology and paediatric general surgery, respectively. Nearly 90% overall respondents felt that a full 2-year paediatric fellowship program was very important and 94% endorsed a collaborative dedicated paediatric urology on call service, with 92% supporting the joint development of transitional care. Urology managed higher numbers of bedwetting (p = 0.04), bladder bowel dysfunction (p = 0.02), endourological procedures (p = 0.04), and robotics (p = 0.04). Paediatric general surgery managed higher numbers of laparoscopic reconstruction (p = 0.03), and posterior urethral valve ablation (p = 0.002).

CONCLUSION

This study represents the first time that a cross-sectional cohort of paediatric urologists from different training backgrounds were compared to assess their productivity, practice patterns and attitudes. Paediatric urology is in a unique position to have two contributing specialities, with the ability to provide optimal transitional and lifelong care. We believe that there should be a strong emphasis on collaboration and to remove any historically-created barriers under policies of equity, diversity and inclusivity.

Characteristics of infant urolithiasis: A single center experience in western Turkey

INTRODUCTION

Urolithiasis (UL) in infancy has different incidence, etiology, presentation and course compared to UL in childhood and in adults. We evaluated the clinical, radiological, metabolic factors and course of infant UL in western Turkey.

METHODS

Medical records of the infants between 1 and 12 months of age with a diagnosis of UL were reviewed retrospectively for gender, gestational age, age at diagnosis, presenting symptoms, past medical history, parental consanguinity, family history of UL, urinary tract abnormalities, urinary tract infections, localization-size-number of stones, course of stones, treatment modality of UL (medical vs surgical) and follow up duration. Patients were grouped as those who did not require surgical intervention (Group 1) and those who underwent any kind of stone surgery (Group 2). Both groups were compared for the study parameters.

RESULTS

There were 80 infants (48 males) with a mean age of 6.0 ± 2.9 months at diagnosis. Mean follow-up duration was 29.7 ± 23.1 months. Two thirds of the patients presented with symptoms/signs not directly related to urinary system. Predisposing factors included metabolic abnormalities in 24 (30%) patients and urinary tract malformations in 9 (11%) patients. Group 1 (n = 58) and Group 2 (n = 22) were not different with respect to the study parameters except for the larger stone size and higher rate of hyperuricosuria in Group 2. Stone size of 4.5 mm has a 72.7% sensitivity and 74.1% specificity for predicting surgical intervention. Infants treated medically and those followed by hydration only did not differ for regression rate of stones and for requirement for surgical intervention. However, metabolic abnormalities were significantly higher in medically treated infants.

CONCLUSION

Every infant with urolithiasis should be evaluated for risk factors. Modification of such predisposing factors when possible may mitigate the notably high recurrence rate of UL in children. Increased awareness of infant UL may allow for earlier detection, improved evaluation and follow up, and may thereby decrease the morbidity of the disease.

Bidirectional association between gallstones and renal stones: Two longitudinal follow-up studies using a national sample cohort

The present study evaluated the associations between gallstones and renal stones using a national sample cohort of the Korean population. The Korean National Health Insurance Service-National Sample Cohort was collected from 2002 to 2013. We designed two different longitudinal follow-up studies. In study I, we extracted gallstone patients (n = 20,711) and 1:4-matched control I subjects (n = 82,844) and analyzed the occurrence of renal stones. In study II, we extracted renal stone patients (n = 23,615) and 1:4-matched control II subjects (n = 94,460) and analyzed the occurrence of gallstones. Matching was performed for age, sex, income, region of residence, and history of hypertension, diabetes mellitus, and dyslipidemia. Crude and adjusted hazard ratios (HRs) were calculated using a Cox proportional hazards model, and the 95% confidence intervals (CIs) were calculated. Subgroup analyses were performed according to age and sex. The adjusted HR of renal stones was 1.93 (95% CI = 1.75–2.14) in the gallstone group (P < 0.001). The adjusted HR of gallstones was 1.97 (95% CI = 1.81–2.15) in the renal stone group (P < 0.001). The results were consistent in all subgroup analyses. Gallstones increased the risk of renal stones, and renal stones increased the risk of gallstones.

Nephrolithiasis predicts ischemic stroke: A longitudinal follow-up study using a national sample cohort

This study sought to evaluate associations between nephrolithiasis and hemorrhagic and ischemic stroke using a national sample cohort from Korea. Data from 2002 to 2013 were collected for individuals ≥ 20 years of age in the Korean National Health Insurance Service (NHIS)-National Sample Cohort. We extracted nephrolithiasis patients (n = 22,636) and 1:4 matched controls (n = 90,544) and analyzed the occurrence of stroke. Matching was performed based on age, sex, income, region of residence, hypertension, diabetes mellitus, and dyslipidemia history. Crude and adjusted hazard ratios (HRs) were calculated using Cox proportional hazard models, and 95% confidence intervals (CIs) were determined. We performed subgroup analyses according to age, sex, and follow-up period. The adjusted HR of ischemic stroke was 1.13 (95% CI = 1.06-1.21) in the nephrolithiasis group (P < 0.001). The relationship between nephrolithiasis and ischemic stroke remained present for the young women and middle-aged men as well as during a follow-up period of ≤ 1 year. The HR for hemorrhagic stroke did not reach statistical significance. The risk of ischemic stroke was higher in the nephrolithiasis patients.

Lack of evidence that nephrolithiasis increases the risk of sialolithiasis: A longitudinal follow-up study using a national sample cohort

Objective

The objective of this study was to evaluate the risk of sialolithiasis in nephrolithiasis patients.

Methods

Using data from the national cohort study from the Korean Health Insurance Review and Assessment Service, we selected 24,038 patients with nephrolithiasis. The control group consisted of 96,152 participants without nephrolithiasis who were matched 1:4 by age, sex, income, region of residence, diabetes, hypertension, and dyslipidemia. The incidence of sialolithiasis in the two groups was compared, with a follow-up period of up to 12 years. The crude and adjusted hazard ratio (HR) of nephrolithiasis to sialolithiasis was analyzed with a Cox-proportional hazard regression model.

Results

The rates of sialolithiasis in the nephrolithiasis group and the control group were not significantly different (0.08% vs. 0.1%, P = 0.447). The crude and adjusted hazard ratios of nephrolithiasis to sialolithiasis were not statistically significant (crude HR = 0.82, 95% confidence interval [CI] = 0.50–1.35, P = 0.448; adjusted HR = 0.81, 95% CI = 0.49–1.33, P = 0.399). Subgroup analyses according to age and sex also failed to reveal statistical significance.

Conclusion

There is no evidence of an increased risk of sialolithiasis associated with nephrolithiasis. We suggest that routine evaluation for sialolithiasis in all patients with nephrolithiasis is not necessary.

Urgent percutaneous nephrolithotomy for acute kidney injury secondary to bilateral stones: is it safe and effective in infants?

PURPOSE

To evaluate the efficacy and safety of urgent percutaneous nephrolithotomy (PNL) for acute kidney injury secondary to bilateral upper urinary stones in infants.

METHODS

A total of seven infants (five boys and two girls), aged from 5 to 12 months, underwent urgent PNL for calculus anuria from September 2011 to March 2013. The initial blood test revealed acute renal injury in all infants. After correcting electrolyte imbalance and acid-base status through medical treatment in a short time without dialysis, all urgent PNL procedures were performed with 16F percutaneous access and small-diameter nephroscopes designed specifically for pediatric surgery on the side with the more dilated pelvis. Stones were fragmented with a pneumatic lithotripter.

RESULTS

Stones were completely removed from the operative side kidneys. The operating time ranged from 35 to 57 min. Blood BUN, serum creatinine, and electrolyte levels returned to normal on postoperative 36 h. There were no major perioperative or postoperative complications and deaths.

CONCLUSIONS

When performed by experienced endourologists, urgent PNL is a safe and effective procedure in infants for acute kidney injury secondary to bilateral upper urinary stones.

[Renal and ureteral stones in V.A.C.T.E.R.L. association: endourological management]

BACKGROUND

The endourological technique is a safe and effective approach in the treatment of large stones in the pediatric population with congenital malformations.

INTRODUCTION

The VACTERL association is a group of congenital malformations that include vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula with atresia, renal defects, and radial upper limb dysplasia. Renal anomalies are found in approximately 90% of patients.

MATERIALS AND METHODS

We present a case of a 7-year-old girl with VACTERL association and cloacal malformations, undergoing multiple surgeries with subsequent Mitrofanoff continent appendico-vesicostomy. She presented at our attention for centimetric left ureteral and inferior pyelo-calyceal stones. She underwent flexible ureteroscopy with laser lithotripsy of both stones. A ureteral catheter and a nephrostomy tube have been left at the end of the procedure.

RESULTS

The ureteral catheter was removed in the 2nd post-operative day, the tubes were removed after a nephrostogram in the 8th post-operative day. The patient is stone-free. No complications were observed in the post-operative time.

CONCLUSIONS

Endoscopy is the method of choice for the management of pediatric urolithiasis with complex renal calculi, due to its low incidence of major complications and a high stone-free rate.

Influence of overweight on 24-hour urine chemistry studies and recurrent urolithiasis in children

Purpose

We investigated the influence of overweight on 24-hour urine chemistry studies and recurrent urolithiasis (UL) in children.

Materials and Methods

A retrospective cohort study was designed to assess children who presented with UL at a pediatric institution between 1985 and 2010. We calculated body mass index percentile (BMIp) adjusted for gender and age according to the 2007 Korean Children and Adolescents Growth Chart and stratified the children into 3 BMI categories: lower body weight (LBW, BMIp≤10), normal BW (NBW, 10<BMIp<85), and upper BW (UBW, BMIp≥85). Twenty-four hour urine chemistry studies (urine volume, creatinine, calcium, oxalate, citrate, and pH) were compared between the 3 BMIp groups. Univariate and multivariate analyses were performed to assess independent risk factors for stone recurrence.

Results

A total of 125 patients were included. The age of the patients in the NBW group was older than that of patients in the LBW group, but 24-hour urine chemistry studies did not differ significantly between the three groups. Mean urine citrate levels were lower (0.273±0.218 mg/mg/d vs. 0.429±0.299 mg/mg/d, p<0.05) and the incidence of hypocitraturia was higher (81.5% vs. 45.7%, p<0.05)) in the recurrent stone former group. In the univariate analysis, hypocitraturia and acidic urinary pH were risk factors, but in the multivariate analysis, only hypocitraturia was a risk factor for stone recurrence (hazard ratio, 3.647; 95% confidence interval, 1.047 to 12.703). In the Kaplan-Meier curve, the hypocitraturia group showed higher recurrence than did the normocitraturia group (p<0.05).

Conclusions

Unlike in adults, in children, overweight adjusted for gender and age was not associated with 24-hour urine chemistry studies and was not a risk factor for recurrent UL. Hypocitraturia was the only risk factor for UL in children.

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.

Metabolic and demographic characteristics of children with urolithiasis in Western Turkey

Pediatric urolithiasis is an endemic disease in Turkey. We evaluated the clinical, radiological and metabolic features of children with urolithiasis in Western Turkey. We retrospectively reviewed the records of 85 children with urolithiasis who were followed-up between 2004 and 2010 in Pediatric Nephrology Department of Celal Bayar University, Manisa. The male/female ratio was 1.23/1. The mean age at diagnosis was 66.1 months (range 3-210 months). Family history of urolithiasis was found in 58 (68.2%) patients. 23 (27%) patients were born from consanguineous marriages. Stones were located in the upper urinary tract in 79 (92.9%) patients. In 66 (77.6%) patients, stones were single-sided and 41 (48.2%) patients had multiple stones. Calcium oxalate stones were the most common one among patients in whom stone analysis was performed (78.5%). Hypocitraturia was the most commonly detected urinary metabolic risk factor. In patients who were under 12 months of age at diagnosis, hypercalciuria was the most commonly seen urinary metabolic risk factor. At the end of follow-up period, 24 patients became free of stone disease and 4 patients had recurrence. In conclusion, metabolic abnormalities are common in pediatric stone patients and are strongly associated with recurrence. Considering that urolithiasis in children is an important risk factor for renal failure, early diagnosis, detailed metabolic evaluation and implementing appropriate treatment and follow-up protocols may prevent recurrence and renal damage.

New horizons in the management of patients with cystinuria

PURPOSE OF REVIEW

Although the formation of cystine stones is seen in only a small fraction of all patients with urolithiasis, this disease is associated with a pronounced morbidity. The difficult clinical management of these patients, with the aim of arresting or decreasing the rate of recurrent stone formation, is well recognized. This review summarizes some recent knowledge.

RECENT FINDINGS

An early and correct diagnosis of cystinuria is fundamental for a successful course of the disease in these patients. Formation starts early in life, and attention to this diagnosis is necessary for the paediatric stone formers. New radiological and biochemical improvements seem useful in this respect. A combination of medical tools is usually necessary to influence the very often, troublesome stone-forming activity. Urine dilution, alkalization and chelating therapy have remained the cornerstones of the therapeutic approach. The importance of a high urine pH has been further emphasized, and the possibility to use acetazolamide is a promising improvement of the medical treatment. In order to increase the compliance and reduce the need of active stone removal, special stone clinics seem to be of particular value. The understanding of the genetic background might open future treatment alternatives.

SUMMARY

Patients afflicted by cystine stone disease need an aggressive medical treatment, gentle stone-removing surgery and careful follow-up.