Urolithiasis in childhood: current management

The pediatric urobiome in genitourinary conditions: a narrative review

The microbial ecosystem within the bladder that can be measured within the urine, or urobiome, is an emerging field of study with little published data regarding children. However, investigations into urobiome research have the potential to significantly impact the understanding of the pathophysiology of genitourinary conditions, as well as potentially identify novel therapeutics. Therefore, both researchers and clinicians should be aware of pediatric urobiome research. The purpose of this review is to highlight the literature around urobiome research in urinary tract infections, nephrolithiasis, and neurogenic bladder; comment on pediatric-specific considerations when reading and interpreting the urobiome literature; and to identify new potential areas of research.

Removal of lower urinary tract stones by percutaneous cystolithotomy: 68 cases (2012-2017)

OBJECTIVE

To describe the use and outcome of percutaneous cystolithotomy (PCCL) for removal of urethral and bladder stones in dogs and cats.

STUDY DESIGN

Retrospective case series.

ANIMALS

Sixty-eight client-owned dogs and cats.

METHODS

Records were reviewed and analyzed for dogs and cats that underwent PCCL between January 2012 and December 2017. Signalment, clinical presentation, laboratory and imaging data, procedure time, use of lithotripsy, biopsy, perioperative and immediate postoperative complications, hospitalization times, stone composition, and urine culture results were recorded. Owners were contacted by phone or email 3 weeks after the procedure. Follow-up communications with the owner and referring veterinarian were also recorded.

RESULTS

Seventy percutaneous cystolithotomies were performed in 59 dogs and nine cats. The median duration of the procedure was 95 minutes (45-420), and lithotripsy was required in 3% (2/70) of PCCL. Complications during the procedure were reported in one case. In eighty-three percent of procedures (58/70), animals were discharged within 24 hours postoperative. Twenty-four percent (16/68) of animals had minor complications (lower urinary tract signs), and one dog had a major complication (surgical wound dehiscence) during the 3 weeks after the operation. Long-term follow-up revealed stone recurrence in 21% of cases followed more than a year after the procedure (7/33).

CONCLUSION

Percutaneous cystolithotomy allowed removal of bladder and urethral stones with rapid postoperative recovery and few major perioperative or short-term postoperative complications.

CLINICAL SIGNIFICANCE

Percutaneous cystolithotomy provides an attractive minimally invasive surgical alternative for removal of lower urinary tract stones in small animals.

Factors Affecting the Success Rate of Percutaneous Nephrolithotomy in Paediatric Patients

In this study, we aimed to determine factors affecting the success rate of percutaneous nephrolithotomy (PNL) in children. The series consisted of 41 consecutive children operated on by the same surgical team for renal calculi with PNL between June 2002 and May 2015 in our institution. A single calyx or pelvic stone was described as simple, while calculi located in more than one location (calyx and pelvis or more than one calices) or staghorn stones were described as complex. The procedure was deemed successful if the patient was completely stone-free (SF) or had residual fragments <4 mm. Thirty-four patients were found to be SF or had residual fragments <4 mm on the postoperative first day, thus the success rate was 82.9%. In complex stones, the success rate was significantly lower (45.5%) than simple stones (96.7%) (p < 0.001). The grade of hydronephrosis (Grade 0–1 vs. Grade 2–3) also had a negative impact on the success, with rates of 92.6% vs. 64.3%, respectively (p = 0.022). Previous urological procedure history on the same side yielded a success rate of 58.3%, whereas the success rate in the primary patients was 93.1% (p < 0.001). The localization of the stone (complex vs. simple), degree of hydronephrosis, and history of previous urological procedures were found to be the factors that affected the success of the paediatric PNL.

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.

Pediatric urolithiasis in Taiwan: a nationwide study, 1997-2006

OBJECTIVE

To investigate the prevalence, incidence, associated risk factors, and treatment of pediatric urolithiasis in Taiwan.

METHODS

The present study used a subset of the National Health Insurance Research Database, known as the Longitudinal Health Insurance Database 2005, which contains the data for all paid medical benefit claims from 1997 to 2006 for a subset of 1 million beneficiaries randomly drawn from the population of 22.72 million individuals during any part of the calendar year 2005. Our analysis included the data of all newly diagnosed pediatric patients with an "International Classification of Disease, 9th revision," diagnosis of urolithiasis from 1997 through 2006.

RESULTS

A total of 1679 pediatric subjects who had newly diagnosed urolithiasis without a previous attack were identified from 1997 to 2006 as the study sample. Of the 1679 patients, 808 were boys (48.1%) and 871 were girls (51.9%). The incidence rate of urolithiasis in 2005 was 0.047%. The peak age of pediatric stone occurrence in the study sample was 15-18 years (49.6%). The most common associated disease was urinary tract infection (34.1% of all subjects). The occurrence rate of pediatric urolithiasis correlated significantly with the urbanization level of the residence and geographic area.

CONCLUSION

Using a nationwide, population-based study provides important clinical and epidemiologic information regarding pediatric urolithiasis. Additional studies are warranted to determine the effect of geographic area and urbanization level on the occurrence of pediatric stone disease.

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.

Essential oil terpenes: adjunctive role in the management of childhood urolithiasis

Essential oil preparation of the terpenic type was introduced for the first time in the 1930s for the management of urolithiasis. Although essential oil preparations are registered in 50 countries, including some developed countries such as the United Kingdom, Italy, and Japan, for use in urolithiasis, no literature has been published in a peer-reviewed English (Anglo-American) medical journal. Recently the use of these terpenes has been investigated in children with urolithiasis and underlying metabolic abnormalities. The aim of this article is to extract the useful and worthy information about the use of these terpenes in urolithiasis from the previous literature as many of these articles are now considered of poor quality for a thorough systematic scientific review. The main disadvantages of most of the old literature about terpenes are the treatment was not followed radiologically and most of these articles represent anecdotal reports of spontaneous passage of calculi and symptomatic improvement of colic in association with the use of terpenes. The other aim is to discuss the possible role of essential oil terpenes in the management of childhood 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 urolithiasis: clinical predictors in the emergency department

OBJECTIVE

The objective of this study was to identify factors that predict the presence of urolithiasis detected with unenhanced computed tomography (UCT) in children.

METHODS

A retrospective study of all subjects <21 years of age who presented to the emergency department at Akron Children's Hospital and underwent UCT of the abdomen between January 2002 and December 2005 was performed. Demographic, clinical, diagnostic, treatment, and disposition data were abstracted by using a standardized form. Univariate and logistic regression analyses of factors associated with urolithiasis were performed.

RESULTS

A total of 339 eligible patients were identified, with 110 cases of urolithiasis detected with UCT for 95 individual patients. The mean age of the study patients was 14.4 years; 72 patients (66%) were female. In 17 cases (15%) of urolithiasis, initial urinalysis results were negative for blood. Fifty-seven stones (51.8%) were ureteral, 26 (23.6%) were renal, and 4 (3.6%) were in the bladder. Among children who did not have a stone identified through UCT, 23 cases (10%) of potentially significant, alternative diagnoses were identified. A history of urolithiasis, a history of nausea and vomiting, the presence of flank pain on examination, and >2 red blood cells per high-power field in urine microscopy were positively associated with urolithiasis. A history of fever or dysuria and costovertebral angle tenderness on physical examination were inversely associated with urolithiasis on UCT scans.

CONCLUSIONS

UCT plays an important role in the diagnostic evaluation of children with flank pain. Approximately 15% of children with urolithiasis do not have hematuria.

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.

Genetic causes of hypercalciuric nephrolithiasis

Renal stone disease (nephrolithiasis) affects 3-5% of the population and is often associated with hypercalciuria. Hypercalciuric nephrolithiasis is a familial disorder in over 35% of patients and may occur as a monogenic disorder that is more likely to manifest itself in childhood. Studies of these monogenic forms of hypercalciuric nephrolithiasis in humans, e.g. Bartter syndrome, Dent's disease, autosomal dominant hypocalcemic hypercalciuria (ADHH), hypercalciuric nephrolithiasis with hypophosphatemia, and familial hypomagnesemia with hypercalciuria have helped to identify a number of transporters, channels and receptors that are involved in regulating the renal tubular reabsorption of calcium. Thus, Bartter syndrome, an autosomal disease, is caused by mutations of the bumetanide-sensitive Na-K-Cl (NKCC2) co-transporter, the renal outer-medullary potassium (ROMK) channel, the voltage-gated chloride channel, CLC-Kb, the CLC-Kb beta subunit, barttin, or the calcium-sensing receptor (CaSR). Dent's disease, an X-linked disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is due to mutations of the chloride/proton antiporter 5, CLC-5; ADHH is associated with activating mutations of the CaSR, which is a G-protein-coupled receptor; hypophosphatemic hypercalciuric nephrolithiasis associated with rickets is due to mutations in the type 2c sodium-phosphate co-transporter (NPT2c); and familial hypomagnesemia with hypercalciuria is due to mutations of paracellin-1, which is a member of the claudin family of membrane proteins that form the intercellular tight junction barrier in a variety of epithelia. These studies have provided valuable insights into the renal tubular pathways that regulate calcium reabsorption and predispose to hypercalciuria and nephrolithiasis.

Pediatric urolithiasis: an 8-year experience of single centre

OBJECTIVE

The objective was to investigate the clinical features and metabolic and anatomic risk factors for kidney stone formation in our patient group.

METHODS

Between 1998 and 2005, 179 children (94 girls, 85 boys) followed in our department because of urolithiasis were enrolled to participate in our study. Clinical presentation, urinary tract infection, stone localisation, positive family history, stone composition, presence of anatomic abnormalities and urinary metabolic risk factors, and treatment modality were evaluated retrospectively.

RESULTS

The mean age at diagnosis of stone disease was 4.5 years (range 0.25-15.3 years). The mean follow-up duration was 8 months (range 1-98). The major clinical presentations of our patients were abdominal pain and/or flank pain in 100 children (55.9%) and macroscopic hematuria in 25 (14%). Urinary tract infection was detected in 20% of patients on admission. Forty-three children (24%) had a urinary tract abnormality and ureteropelvic junction obstruction was the most common abnormality. A family history of stone disease was recorded in 98 patients (54.7%). Stones were located within the renal parenchyma in 90 patients. Hypercalciuria and hyperuricosuria were detected in 42.3 and 54.8% respectively. Stone analysis was performed in 63 children and calcium oxalate was a major mineral. Surgical treatment was performed in 49 children and extracorporeal shock wave lithotripsy (ESWL) in 41 children.

CONCLUSION

We think that urolithiasis remains a serious problem in children in our country. Family history of urolithiasis, urologic abnormalities (especially under the age of 5 years), metabolic disorders and urinary tract infections tend to indicate childhood urolithiasis.

Extracorporeal shock wave lithotripsy in the management of pediatric urolithiasis

The main objective of this paper was to evaluate the efficacy and safety of the management of pediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL). Between November 1988 and July 2000, 165 renal stones, 53 ureteral stones, and 5 bladder stones were treated in 126 pediatric patients using Siemens Lithostar lithotriptor. The ESWL treatments ranging from 1 to 7 were needed per patient (mean: 2.1). One ESWL session was performed for 49.6% of stones, two for 24.6%, three for 13.0 %, four for 5.6% and > 4 for 8.2%. The success rate for renal stone units (asymptomatic fragments less than 4 mm) was 88.2%, stone-free rate was 49.0%. The stone-free rate for ureteral stone units was 87.5%, but was 75% for bladder stones. The overall results of ESWL treatment in 126 children was satisfactory: the success rate was 90.5%, stone-free rate was 51.6%, residual fragments > 4 mm were 9.5%. General anesthesia was required in 65 children (136 treatments) under the age of 10, and only in 18 children (40 treatments) in the age 11-14. Auxiliary procedures, such as double J stent and percutaneous nephrostomy (PCN) were used in 19 and 7 patients, respectively. Perirenal hematoma in one patient and hematomas in enteric wall in another one patient were the only major complications managed conservatively without consequences. Low energy lithotripsy with the Siemens Lithostar in our series of pediatric patients was safe and relatively effective.

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.

Pediatric kidney stones: Long-term outcomes

OBJECTIVES

To determine the specific risks for recurrent stone disease and which initial evaluations resulted in an effective reduction of risk, we undertook a long-term follow-up study of children who had experienced upper tract urinary stones.

METHODS

Identified patients were contacted and interviewed using a structured questionnaire. The patient data were subcategorized and analyzed.

RESULTS

The results demonstrated that our population had a recurrence rate similar to the reported adult stone recurrence rates. No evidence was found of impaired growth or development. Our population of noncircumcised boys did not demonstrate a high risk of struvite stones. Surgical techniques have evolved. Anatomic and metabolic factors were not a predictor of an adverse risk of recurrence. Cystinuria may carry extra risk, although our numbers were not sufficient to be sure.

CONCLUSIONS

Extensive metabolic screening of children with upper tract urinary stones is not supported by the data from our patients. Testing for cystinuria is justified. The principles of screening and surveillance should match the recommended care of adults with stone formation.

Pediatric urolithiasis: etiology, specific pathogenesis and medical treatment

Pediatric urolithiasis is an endemic disease in certain parts of the world, namely Turkey and the Far East. As a recurrent pathology which may reveal functional as well and morphologic changes in the urinary tract, environmental factors together with urogenital abnormalities should be evaluated thoroughly in each patient. The aims of management should be complete clearance of stones, treatment of urinary tract infections, preservation of renal function and prevention of stone recurrence. In addition to certain minimally invasive stone removal procedures, treatment of pediatric urolithiasis requires a detailed metabolic evaluation in all patients on an individual basis. Obstructive pathologies have to be corrected immediately and children with a positive family history should be followed carefully with respect to a high likelihood of stone re-growth and recurrence. Although specific management of each metabolic abnormality seems to be the key factor in the medical management of stone disease, as general advice each child should be forced to adequate fluid intake which will reveal the urine volume increase in accordance with the body mass index. Moreover, medical therapeutic agents which increase urine citrate levels should be encouraged.

High incidence of kidney stones in Icelandic children

All children less than 18 years of age who were diagnosed with a first episode of kidney stones at pediatric referral centers in Iceland during the years 1995-2000 were studied retrospectively. The diagnosis was based on clinical features and results of imaging studies. Patients were invited for evaluation at the end of the study period. Twenty-six patients (15 females, 11 males), median age 9.4 (range 0.2-14.9) years, experienced 34 episodes of kidney stones. The annual incidence was 5.6 and 6.3 per 100,000 children less than 18 and 16 years of age, respectively. Abdominal pain was the most common symptom (N=17; 69%) and urinalysis revealed hematuria in 21 patients (80.8%), sterile pyuria in 17 (65%), and 2,8-dihydroxyadeninuria in two. Six patients (23%) had positive urine cultures at the time of diagnosis and five (20%) had urinary tract anomalies. Family history of kidney stones was positive in one third of patients. Metabolic risk factors for stone formation were identified in 22 of 23 patients (96%) who underwent evaluation. Hypercalciuria, the most common metabolic risk factor, was identified in 18 patients (78%). Stones passed spontaneously in nine patients (35%) and six patients had recurrent stone episodes. The incidence of kidney stones in Icelandic children is high compared with other Western populations, affecting females more than males. Underlying metabolic risk factors were identified in most patients.

[Evaluation of renal stone disease: metabolic study]

Renal stone formation is a multifactorial process in which all the information obtained from the patient (medical history, imaging tests, stone analysis, metabolic study and physicochemical urine analysis) shows a different facet of the same process. Consequently, all these investigations should be evaluated together. In half of all patients, stone formation is secondary to the presence of metabolic alterations in urine, of which the most frequent is idiopathic hypercalciuria. The second most frequent cause is infection and/or urinary malformations, while hereditary enzyme defects are highly unusual. Reference values for urinary excretion of lithogenic metabolites (calciuria, uricosuria, oxaluria, citraturia, etc.) are essential for an adequate metabolic study, since urinary excretion depends on multiple factors, which have been described in the various publications in the literature. Physicochemical study evaluating saturation of the various salts dissolved in urine should be performed. These saturations are currently considered to be a highly useful index for determining the risk of crystallization and stone formation in patients with lithiasis and for evaluating the effectiveness of treatment. Lastly, the metabolic profile of renal lithiasis in children resembles that in adults, suggesting that predisposition to renal lithiasis begins in childhood. The early detection of the metabolic alterations observed in these patients will reduce the incidence of this disease in both children and adults.

Medical management of pediatric stone disease

Childhood urolithiasis remains endemic in certain parts of the world, namely, Turkey and the Far East. The prevalence of nephrolithiasis in North American children varies widely among geographic regions and accounts for 1 per 1000 to 1 per 7600 pediatric hospital admissions. Stones occur in children of all ages. The clinical manifestations of stone disease are often more subtle in children when compared with the dramatic adult presentation. This article discusses the evaluation and medical management of pediatric stone disease.

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.

Pediatric urolithiasis

Pediatric stone disease is a frequently underestimated entity that can present unique problems in its management. The condition stems from any of a number of underlying, causative factors, and the significant possibility of recurrence must always be borne in mind. The primary care physician should be aware that the condition is readily treatable by an experienced pediatric urologist who has a range of treatment modalities at his or her disposal; however, overall success is governed by a timely referral and subsequent long-term follow-up to ensure the maintenance of a stone-free state.

Extracorporeal shock wave lithotripsy is highly effective for ureteral calculi in children

PURPOSE

Treatment of ureteral calculi in the pediatric population represents a unique challenge. Extracorporeal shock wave lithotripsy (ESWL*) and ureteroscopy have been advocated for the treatment of such stones. We present our experience with ESWL monotherapy for ureteral stones in children in the last decade.

MATERIALS AND METHODS

Between 1989 and 1999 we treated 21 boys and 17 girls with a mean age of 8 years (range 8 months to 14 years) with ureteral stones at our institution. Records were reviewed and analyzed for presentation, metabolic and anatomical anomalies, stone size and location, outcome and complications. Average stone size was 9.5 x 6.5 mm. (range 3 to 32). Stones were in the upper ureter in 17 cases, mid ureter in 2 and lower ureter in 19. All patients underwent ESWL with a Dornier HM3 lithotriptor under general anesthesia. Nephrostomies were placed in an anuric infant with bilateral ureteral obstruction and in 2 patients with nonfunctioning kidneys (4 renal units). Ureteral catheters were used in 15 patients for better identification and localization of the stone during ESWL. The catheters were removed immediately postoperatively.

RESULTS

Of the patients 31 (81.5%) were free of stones after 1 session of ESWL, 5 (13.1%) after 2 and 1 after 3. One patient underwent ureteroscopy for residual fragments after 2 ESWL sessions. The stone-free rate following 1 ESWL session was 100% for ureteral calculi 10 mm. or smaller regardless of location. Of the 12 patients with stones larger than 10 mm. 8 (67%) were free of stones following 1 ESWL session. The overall success rate of ESWL was 97.3%. No child had postoperative urinary infection or ureteral obstruction.

CONCLUSIONS

ESWL is an efficient and safe modality for the treatment of pediatric ureteral stones.

EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY IS HIGHLY EFFECTIVE FOR URETERAL CALCULI IN CHILDREN

PURPOSE

Treatment of ureteral calculi in the pediatric population represents a unique challenge. Extracorporeal shock wave lithotripsy (ESWL*) and ureteroscopy have been advocated for the treatment of such stones. We present our experience with ESWL monotherapy for ureteral stones in children in the last decade.

MATERIALS AND METHODS

Between 1989 and 1999 we treated 21 boys and 17 girls with a mean age of 8 years (range 8 months to 14 years) with ureteral stones at our institution. Records were reviewed and analyzed for presentation, metabolic and anatomical anomalies, stone size and location, outcome and complications. Average stone size was 9.5 x 6.5 mm. (range 3 to 32). Stones were in the upper ureter in 17 cases, mid ureter in 2 and lower ureter in 19. All patients underwent ESWL with a Dornier HM3 lithotriptor under general anesthesia. Nephrostomies were placed in an anuric infant with bilateral ureteral obstruction and in 2 patients with nonfunctioning kidneys (4 renal units). Ureteral catheters were used in 15 patients for better identification and localization of the stone during ESWL. The catheters were removed immediately postoperatively.

RESULTS

Of the patients 31 (81.5%) were free of stones after 1 session of ESWL, 5 (13.1%) after 2 and 1 after 3. One patient underwent ureteroscopy for residual fragments after 2 ESWL sessions. The stone-free rate following 1 ESWL session was 100% for ureteral calculi 10 mm. or smaller regardless of location. Of the 12 patients with stones larger than 10 mm. 8 (67%) were free of stones following 1 ESWL session. The overall success rate of ESWL was 97.3%. No child had postoperative urinary infection or ureteral obstruction.

CONCLUSIONS

ESWL is an efficient and safe modality for the treatment of pediatric ureteral stones.

The vesical calculus

Bladder calculi account for 5% of urinary calculi and usually occur because of foreign bodies, obstruction, or infection. Males with prostate disease or previous prostate surgery and women who undergo anti-incontinence surgery are at higher risk for developing bladder calculi. Patients with SCI with indwelling Foley catheters are at high risk for developing stones. There appears to be a significant association between bladder calculi and the formation of malignant bladder tumors in these patients. Transplant recipients are not at increased risk for developing vesical calculi in the absence of intravesical suture fragments and other foreign bodies. Patients who undergo bladder-augmentation procedures using a vascularized gastric patch appear to be protected from vesicolithiasis, perhaps by the acidic environment. Ileum and colon tissues, however, are colonized by urease-producing organisms, producing an alkaline pH that promotes stone formation. Children remain at high risk for bladder-stone development in endemic areas. Diet, voiding dysfunction, and uncorrected anatomic abnormalities, such as posterior urethral valves and vesicoureteral reflux, predispose them to bladder-calculus formation. Finally, there are a number of techniques and modalities available to remove bladder stones. Relieving obstruction, eliminating infection, meticulous surgical technique, and accurate diagnosis are essential in their treatment.

Renal stone disease in children

Renal stone disease has been regarded as an uncommon problem in children compared to adults. However, increased awareness of this problem in children may lead to early intervention preventing long-term consequences on the kidney and the urinary tract. This article reviews the epidemiology, pathogenesis, and the most common etiologies of renal stones in children. The clinical features and diagnostic and therapeutic modalities for the specific etiologies are also outlined. Using these guidelines may be helpful not only in the treatment but also in the prevention of renal stones.

Treatment of pediatric urolithiasis between 1984 and 1994

PURPOSE

We report our experience with the management of pediatric urolithiasis during a 10-year period. Our aim was to assess the impact of new technology in the treatment of pediatric urolithiasis.

MATERIALS AND METHODS

We retrospectively reviewed the records of all patients up to age 18 years in whom urolithiasis was treated from 1984 to 1994. In 37 cases 24-hour urine collections were available for metabolic evaluation.

RESULTS

A total of 100 pediatric patients was treated for urolithiasis. Mean followup was 36 months. A total of 79 patients underwent 115 procedures for symptomatic urolithiasis and 21 were treated nonoperatively. In 42 patients structural anomalies of the urinary tract required additional management. Metabolic abnormalities in 48 patients included hypercalciuria in 19, defined as greater than 4 mg./kg./24 hours calcium by 24-hour urine collection. Only 24 of the 100 patients had no identifiable predisposing factors. Procedures included shock wave lithotripsy in 42 cases, basket extraction with or without ureteroscopy in 20, percutaneous nephrostolithotomy in 11 and litholapaxy in 12. Open surgery included cystolithotomy in 10 cases and other forms of open lithotomy in 15. Thus, open surgical removal was necessary in 1 of 5 cases.

CONCLUSIONS

Compared to the traditional mode of stone treatment, fewer patients required open surgery. Our results indicate that a comprehensive approach to the care of pediatric patients with urolithiasis requires attention to metabolic and structural abnormalities.

Pediatric urolithiasis: to cut or not to cut

Urolithiasis is a major source of morbidity in children of the third world. Since its advent in 1982 and despite uncertainties about the long-term effects on the kidney, extracorporeal shock wave lithotripsy (ESWL) has rapidly replaced traditional surgery in the management of this condition. A retrospective study was conducted to compare the outcome of ESWL with that of open surgery in the management of paediatric urolithiasis in a single institution between November 1988 and December 1991. Emphasis was placed on the rate of stone clearance, complications, duration of follow-up, and cost of treatment of each modality. A total of 83 patients under 14 years of age underwent management of 101 stones; the stones were located in the kidneys (63), ureters (13), or bladder (25). Thirty-one patients who enrolled directly through the Lithotripsy Clinic underwent a total of 65 ESWL sessions for 44 calculi (mean, 2.1 sessions per patient). The overall stone clearance rate was 82%, with an 83% clearance rate for renal stones. There were three failures. Nine patients did not return after the first ESWL session, and by the end of 6 months, 93.5% were lost to follow-up. The cost of ESWL ranged from $600 to $1,000 (mean, $780). Fifty-two children were managed through the Pediatric Surgery Clinic and underwent open surgery (57 stones). The overall stone clearance rate was 96%, with a clearance of 88% for renal calculi. There were two wound infections and no deaths. All patients returned for the first follow-up visit, but by the end of 6 months, only 34.5% were available for follow-up. The total cost of treatment ranged from $520 to $900 (mean, $580). The authors believe that with the present level of knowledge, use of the lithotriptor should be restricted to children with small stones and/or those for whom long-term follow-up is possible.

A review of pediatric cases of urinary tract calculi

A retrospective review was performed of the records of 93 children with urinary tract calculi treated during a 10-year period (1983 to 1992). Two distinct groups of patients were identified. One group comprised 63 Aboriginal children, mainly from the northern region of Western Australia, who presented at a young age (average, 2.8 years) with urinary tract infections and failure to thrive. The other group comprised of 30 non-Aboriginal children, mainly from the metropolitan region, who presented at an older age (average, 6.7 years) with abdominal and flank pain. Calculi were located in the upper urinary tract in 85 children (91.4%) and in the bladder in eight (8.6%). Most patients underwent open surgical procedures for removal of their calculi, and the overall success rate was 86%. In recent years, percutaneous nephrolithotomy has been used successfully in selected patients with renal pelvic calculi. This method seems to be the trend for the future.

Urinary stones in children in Zaria

In a period of 16 years, 22 boys whose ages ranged from 10 months to 15 years were treated for stones occurring predominantly in the lower urinary tract. These boys represented 9.6/100,000 paediatric admissions, indicating the rarity of urinary stones in children in Zaria. Congenital obstructing lesions were present in 13 (59%) and the urine was infected in eight cases, most frequently by Klebsiella spp.

Percutaneous nephrolithotomy in children

Percutaneous nephrolithotomy was performed on 18 children with renal calculi. No mortality resulted from this procedure and hemorrhage was the major complication. At the end of treatment 67% of the patients were stone-free and 82% of targeted stones were removed. Percutaneous nephrolithotomy can be considered a successful treatment in the management of the pediatric patient with renal calculi.

Urolithiasis in a children's hospital: 1985-1990

We performed a retrospective study of patients who had urinary tract stones and were seen at our hospital from 1985-1990. The study was intended to determine the prevalence of urolithiasis and optimal approaches to imaging. Clinical data and imaging studies of 87 patients were reviewed. The mean age was 15.7 years with a range of 3 months to 44 years. Fifty-four percent of patients were male. Most patients had a known predisposing cause for urolithiasis; patients with myelodysplasia and structural urologic problems predominated. Plain films were performed in 77 patients; 57% showed stones. Ultrasonograms were performed in 71 patients; 77% showed stones. Excretory urograms (EU) were performed in 49 patients; 84% showed either stones or their effect on the urinary tract. Computed tomographic (CT) scan was performed in 25 patients; all showed stones.

Endoscopic manipulation of ureteral calculi in children by rigid operative ureterorenoscopy

To date, rigid operative ureterorenoscopy with ultrasound lithotripsy for the treatment of ureteral calculi has been performed only in adults or older children. The size of the instrument with the working channel for the ultrasound probe has been considered unsuitable for delicate anatomical structures, such as those of children younger than 4 years. We performed 8 ureterorenoscopic examinations in 7 patients (3 boys) 3 to 8 years old and have demonstrated that the 11.5F ureteroscope can be inserted without difficulty into the ureteral meatus of a 3-year-old boy. Introduction of the instrument is facilitated by the use of the Perez-Castro irrigation pump. This procedure does not lead to any urethral or ureteral damage, nor is vesicoureteral reflux shown on a postoperative cystogram. This technique allows extracorporeal shock wave lithotripsy to be extended also to small children, offering the possibility of easy and successful management of any residual steinstrasse.

Urolithiasis in children: current medical management

The mechanism of stone formation in the urinary tract is reviewed. Diet, urinary tract infection and metabolic disorders account for the different epidemiological patterns of stone formation. The diagnosis and management of renal tract calculi are discussed. Calcium stones are associated with hypercalciuria, urine acidification defects, the use of furosemide in premature babies, hypercalcaemia, hyperoxaluria, hyperuricosuria, an alkaline urine and hypocitraturia. Uric acid stones occur in acid urine, from increased purine synthesis with lympho- or myeloproliferative disorders or from several inborn errors of purine metabolism which can also cause xanthine or dihydroxyadenine stones. Cystinuria, inherited as an autosomal recessive disorder is best treated with a low sodium diet, a fluid intake exceeding 40 ml/kg per day maintaining urine pH between 7.5 and 8 and, if necessary, with oral penicillamine. Oxalate stones occur in relation to diet, bowel disease and primary inherited defects in oxalate metabolism. Urinary tract infection causing struvite and carbonate apatite formation is the commonest cause of stones in Europe.

Recurrent and residual renal calculi in children

One hundred and thirteen children with non-metabolic urinary tract calculi were operated on between 1960 and 1983. One hundred were followed up for 3 to 17 years (mean 8.2). Seventeen children (15%) developed recurrent calculi after complete clearance at the initial operation and in 13 of these the stones recurred within 5 years. Proteus urinary infection was a constant feature of stone recurrence. Five patients required re-operation for removal of the recurrent calculus. Small residual caliceal fragments were left behind in 17 children but only 3 required surgical removal.