The aetiological and clinical pattern of childhood urolithiasis in Saudi Arabia

The clinical and aetiological pattern in 85 stone-forming children presenting to an integrated nephrourological service in Riyadh is reviewed. All patients were below the age of 15 years, the male to female ratio being 2∶1. Only 2 children presented with bladder calculi. The remaining all had upper tract stone and, in 12 cases, these were bilateral. Of 34 calculi recovered for analysis, one-third was predominantly calcium oxalate and a further third was composed of uric acid or urate. Four patients had cystine stones and the remaining 7 presented mixed calcium stones, 6 (17.6%) being struvite and infection-related. Of the 85 patients 55 were treated successfully with extracorporeal shock wave lithotripsy, 16 underwent surgery and 7 had their stones removed by endourological procedures. In the remaining 7 children, stones dissolved or were passed spontaneously during medical therapy. Nine children (10.6%) showed a primary metabolic defect leading to their stone formation, 10 (11.8%) had a predisposing anatomical anomaly and 15 (17.6%) presented with urinary tract infection. Of the remaining 51 patients (60%) with idiopathic disease, 6 showed hypercalciuria on investigation and 2 children may have formed their stones due to prolonged recumbency.     

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.     

Clinical analysis of urolithiasis in Poh Ai Hospital of I-Lan, Taiwan, R.O.C.--a comparative study with urolithiasis in Japan]

Between August 1987 and December 1990, 546 patients were admitted to the department of Urology at the Poh Ai Hospital of I-Lan, Taiwan, R.O.C. for the treatment of urinary stones. These urinary stone cases accounted for 50 to 60% of all urology patients admitted. The incidence of urolithiasis in I-Lan was estimated at 147/100,000 population in 1990. There were 402 male patients and 144 female patients, The male to female ratio was 2.8: 1. There were 450 upper urinary tract stones (kidney, ureter) in 314 males and 136 females, and 79 lower urinary tract stones (bladder, urethra) in 72 males and 7 females. The ratio of upper to lower urinary tract stones was 6:1. Endourological treatments such as percutaneous nephrolithotripsy and transurethral ureterolithotripsy have increased rapidly in recent years. A summary of the present analysis for composition of 365 stones follows. The most frequent type was calcium-containing stone (92.3%), followed by infection stone (4.7%), then uric acid (UA) stone (3.0%). There were no UA stones found in the female patients. According to urinalysis criteria of more than 10 WBC/HPF (x 400), pyuria was found in 67 cases of 334 metabolic stones (20.1%), and 11 cases of 17 infection stones (67.7%). There were neither pediatric case of stone formation nor cystine stones.     

Pediatric urolithiasis in Kuwait

In this retrospective study, 31 Kuwaiti children with renal stones were reviewed between January 1996 and September 2000. Male to Female ratio was 2.1:1 with a mean age at presentation of 38 months. Family history of renal stones was reported in 58%. Stones were localized to the kidneys in 74.1%,to ureters in 6% and to the bladder in 9.6%.Bilateral stones were found in 64.5%. Clinical manifestations included: hematuria in 70.9%, passage of stones in 64.5%, abdominal pain in 41.9%, urinary tract infections in 29%, sterile pyuria in22.9% and urine retention in 16%. Causes of stone formation included hypercalciuria in 38.7%, hyperoxaluria in 19.3%,cystinuria in 12.9%, xanthinuria in 12.9%, urinary tract infection in 3.2%,obstruction in 9.6% and idiopathic in 3.2%. In conclusion, lithogenic metabolic causes were found to be the major predisposing factors to stone formation among Kuwaiti children whereas diet and environmental factors played a trivial role.     

Urolithiasis in Tunisian children: a study of 120 cases based on stone composition

The composition of urinary stones in children depends on socioeconomic conditions and hygiene, geographical area, and dietary habits. We analyzed urinary stones from 120 consecutive Tunisian children (81 males, 39 females) aged 5 months to 15 years. The stone was located in the upper urinary tract in 91 cases (76%). Stone analysis included both a morphological examination and an infrared analysis of the nucleus and the inner and peripheral layers. The main components of bladder calculi were whewellite (69%) and struvite (22%), whereas the main component of upper urinary tract calculi was whewellite (67%). The nucleus of bladder stones was composed of ammonium urate (45%), struvite (28%), cystine (10%), and carbapatite (7%). The nucleus of kidney and ureteral calculi was mainly composed of ammonium urate (38%), whewellite (24%), carbapatite (13%), or struvite (11%). Based on stone composition, urinary tract infection was involved in the nucleation or growth of a third of calculi. Endemic urolithiasis involving simultaneous nutritional, metabolic, and infectious factors, and defined by its nucleus composed of ammonium urate without struvite, represented 40% of cases. Exclusive metabolic factors – including genetic diseases such as primary hyperoxaluria, cystinuria, and hypercalciuria – were responsible for less than 25% of cases. Received: 6 March 1998 / Revised: 22 March 1999 / Accepted: 22 March 1999     

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

To study prospectively the risk factors and etiology of urolithiasis in all stone patients aged <15 years admitted from 1991 to 1999 to the Arabkir hospital in Yerevan. Stones were obtained by surgery (64%), extracorporeal shockwave lithotripsy (ESWL) (7%) or cystoscopic extraction (4%); 25% passed spontaneously. All were examined by infrared spectroscopy, and spot urines were analyzed chemically. 198 patients, 180 (68% males) with renal stones and 18 (83% males) with primary bladder stones, were studied. Calcium oxalate (CaOx) was the predominant constituent in 62% of the kidney stones, followed by struvite (17%), calcium phosphate (7%), uric acid (7%), ammonium acid urate (5%), and cystine (2%). Bladder stones contained CaOx in 72%, uric acid in 22% and ammonium acid urate in 6% of patients. Etiology was obviously metabolic in 5% and possibly metabolic in 26%. Twenty percent of stones were infectious, and 19% were endemic (9% bladder and 10% kidney stones); 4% were secondary to urinary stasis with malformation but no infection. Etiology in 26% remained unknown. Stone composition and metabolic etiology are similar to that in central Europe and North America. In contrast, infectious calculi and particularly endemic stones are still common, although becoming less so now. Urolithiasis in Armenia thus reflects the transition from a rural to an urban society. Received: 17 January 2001 / Revised: 24 April 2001 / Accepted: 24 April 2001     

Urolithiasis in childhood: Metabolic evaluation

In order to determine metabolic disorders in children with urolithiasis, 50 patients with urinary calculi were studied. Abdominal pain and/or haematuria were the most predominant symptoms. Surgical procedures were required in 22% of these children and urinary tract infection was observed in 34% of this group. Only 2 children had anatomical malformations of the urinary tract. Absorptive hypercalciuria (32%), renal hypercalciuria (34%) and uric acid hyperexcretion (24%) were the most common metabolic abnormalities in these children. We were unable to find an underlying metabolic abnormality in only 14% of the patients. These data suggest that appropriate metabolic study will allow rational management of children with urinary stones.     

Catheter-less suprapubic cystolithotomy in children

Bladder stones in children are common in developing countries and the procedure of choice for their removal is suprapubic cystolithotomy. It is standard practice to drain the bladder for a few days post-operatively to prevent urinary leakage. We have observed that, if the bladder is closed meticulously in 2 layers, bladder drainage by means of a catheter is not required. We have analysed 86 children treated by suprapubic cystolithotomy without a catheter. Size of the stones and intra-operative findings were noted and it was found that 85% of the patients had an excellent result; 10% had a satisfactory result and 4.7% were unsatisfactory. The advantages of the procedure and selection of the patients are discussed.     

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.     

Metabolic factors in the causation of urinary tract stones in patients with enterocystoplasties

Stones are a common complication of the storage of urine in intestinal reservoirs. Previous studies have identified predisposing physical characteristics in the reservoirs. Biochemical and dietary factors have been little investigated. Fifteen patients (6 males and 9 females) who had undergone various enterocystoplasty operations and who had subsequently formed either upper or lower urinary tract stones were investigated. The programme has been previously described and included stone, blood and urine analysis and dietary review. Comparison was made with 15 age- and sex-matched idiopathic stone formers with normal bladders. Stones were infective in origin in 86% of cases, and 14% were sterile. Metabolic screen showed that 80% of enterocystoplasty patients had risk factors for at least three different types of stone. All patients had raised pH (mean 6.93) and hypocitraturia. Five had a raised alkaline phosphatase. Raised serum and urinary calcium, hyperoxaluria and hyperuricosuria were found in 33% of patients. Five had a 24-h urine volume below 1.6 l/day. All patients had a high risk index (P _SF) for phosphatic stones and 12 also for calcium oxalate stones. Compared to age-and sex-matched idiopathic stone-formers, the urine had a higher pH, sodium and protein excretion and a lower calcium and citrate excretion. Although the patients were already selected as stone-formers, the data show that metabolic and dietary factors are present. They may be as important in the aetiology of the stones, as the already recognised factors of infection and poor reservoir drainage. Investigation should include such factors, the presence of which may be taken into account in a prophylactic regime.     

The impact of contemporary bladder management techniques on struvite calculi associated with spinal cord injury.

OBJECTIVE: To evaluate the incidence, risk factors and complications of upper tract struvite calculi, often associated with spinal cord injury (SCI), as such patients have a high incidence of urinary infection complicating their neurogenic voiding dysfunction, by reviewing a large population of patients with SCI in whom modern techniques of bladder management were used. PATIENTS AND METHODS: Between 1982 and 1996, 1669 patients with SCI were admitted to our institution; 1359 of these patients sustained their injuries during the study period. During this time, their bladder management was based on urodynamic and imaging criteria, using techniques such as early intermittent catheterization, sphincterotomy and bladder augmentation where possible to create a catheter-free, low-pressure reservoir. All instances of upper tract struvite calculi in this population were documented. Risk factors for stone development, presentation and complications, management and recurrence rates were assessed. RESULTS: Over the 15 years, 58 patients (3.5% of the SCI population) were treated for a total of 144 episodes of struvite calculi. The incidence of stones in those injured since 1982 was 1. 5%; 67% of these patients had complete spinal cord lesions, 54% had lesions of the cervical cord and 53% developed their first stone >10 years after injury. Only 22% presented within 2 years of injury. The group of patients developing stones had a significantly higher incidence of indwelling catheters (49%), bladder stones (52%) and vesico-ureteric reflux (28%) than those who were stone-free. The development of recurrent urinary tract infections was the most common mode of presentation. The stone-free rate after treatment was 87%. Normal renal function was preserved in 72% of patients. CONCLUSIONS: In a large population of patients with SCI managed using contemporary bladder techniques the incidence of upper tract calculi was 3.5%; 30% of these stones were complete or partial staghorns. Those patients with complete cord lesions, permanent indwelling catheters and vesico-ureteric reflux were at the highest risk. Stone clearance was 87% and recurrent stones occurred in 69% of patients. Struvite renal calculi continue to be a significant problem in the spinal cord injury population.     

Urinary stone composition in North-East Thailand

Stones removed from 120 adults and 22 children were analysed for chemical composition. Calcium oxalate was the main component of both adult (49%) and childhood (44%) stones. Calcium stones formed the major type in adults and were slightly more common in males, whereas urate/uric acid stones were predominant in children and were more common in girls. In adults, the stones were usually found in the upper urinary tract (UUT) and were mainly of calcium type (72%), while all three types were found in almost equal amounts in the lower urinary tract (LUT). Magnesium ammonium phosphate and urate/uric acid were the stones found mainly in the upper and lower urinary tracts respectively of children.     

Clinical studies on childhood urolithiasis during the past 22 years

We have studied retrospectively 68 children who presented with urolithiasis between 1965 and 1986. Male to female ratio was 1.83 to 1 and the mean age was 9.5 years. Fifty four children (79%) had calculi in the upper urinary tract, 9 (13%) had in the lower, and 4 (6%) had calculi both in the upper and lower urinary tract. The most common presenting symptoms were gross hematuria (53%) and abdominal or flank pain (38%). Predisposing factors could be found only in 21 children (31%). Twenty four of the 68 patients (35%) had open surgery and 16 patients (24%) passed their stones spontaneously. Twenty one stones were analyzed by infrared spectroscopy. Infectious stone was more frequent than in adult cases. Among children five years old and younger, infectious stone was the most frequent. Among children over five years old, the number of idiopathic calcium stone has been on the increase with the years.     

Renal stone disease in spinal-cord-injured patients

Renal stone disease is common among patients with spinal cord injury (SCI). They frequently have recurrent stones, staghorn calculi, and bilateral stone disease. The potential risk factors for stones in the SCI population are lesion level, bladder management strategy, specific metabolic changes, and frequent urinary tract infections. There has been a reduction in struvite stones among these patients, likely as a result of advances in their urologic care. The clinical presentation of stone disease in patients with SCI may involve frequent urinary infections or urosepsis, and at the time of presentation patients may need emergency renal drainage. The proportion of patients who have their stones treated with different modalities is largely unknown. Shockwave lithotripsy (SWL) is commonly used to manage stones in patients with SCI, and there have been reports of stone-free rates of 50% to 70%. The literature suggests that the morbidity associated with percutaneous nephrolithotomy in these patients is considerable. Ureteroscopy is a common modality used in the general population to treat patients with upper tract stone disease. Traditional limitations of this procedure in patients with SCI have likely been overcome with new flexible scopes; however, the medical literature has not specifically reported on its use among patients with SCI.     

Predisposing factors in bladder calculi. Review of 100 cases

One hundred patients, aged twenty to ninety-two years, underwent 111 procedures for removal of bladder calculi. Most patients (88) had some type of bladder outlet obstruction. Two types of stones were identified: those that had apparently formed in the upper tract and been trapped in the bladder (17 cases) and those that appeared to have formed in the bladder in the presence of various types of outlet obstruction. Stone analysis revealed uric acid stones in 50 percent, calcium oxalate stones in 19 percent, and stones of mixed composition in 31 percent. Five patients had metabolic abnormalities predisposing to stone formation; in 2 cases, these abnormalities were discovered during the evaluation for stone disease. Treatment depended on stone characteristics, associated pathology, and the general health of the patient. A review of the literature with regard to the morbidity and mortality of combining treatment of vesical calculi and bladder outlet obstruction secondary to prostatic obstruction is included.     

The outcome of bladder neck closure in children with severe urinary incontinence

PURPOSE: We evaluated the outcome of children who underwent bladder neck closure for the management of severe urinary incontinence. MATERIALS AND METHODS: Bladder neck closure was performed in 12 patients with bladder exstrophy, 4 with myelomeningocele and 4 with urogenital sinus anomalies for severe urinary incontinence that persisted after multiple failed bladder outlet procedures. The effectiveness of bladder neck closure and the need for subsequent surgeries were ascertained. RESULTS: Mean followup was 5.4 years (range 1 to 12). At 3 months after surgery 40% of the patients were completely dry, 20% had leakage via the stoma and 40% had a urethral fistula. After additional surgeries 85% of the patients were completely continent 2 years following bladder neck closure (15% declined further surgeries or had an ileal conduit). Of the 15 patients with followup longer than 3 years only 40% remained completely dry, and leakage via the stoma developed in 47% after being dry for 1 year. Repeat urodynamic studies did not show any adverse changes in bladder dynamics in the incontinent patients. Stomal stenosis occurred in 30% of the patients and bladder stones developed in 40%. None of the patients had hydronephrosis or bladder perforation. The early complication of fistula formation and the late development of leakage via the stoma appear to be related in part to compliance with intermittent catheterization. CONCLUSIONS: Bladder neck closure is an effective method of achieving urinary continence in children in whom other bladder outlet surgery has failed. However, its success is dependent in part upon compliance with intermittent catheterization. Finally children who have undergone bladder neck closure are at an increased risk for stomal stenosis and bladder stones.     

泌尿系结石成分分析及意义

目的：分析赤峰地区泌尿系结石成分特点,对预防泌尿系结石的复发提供帮助。方法：对89例泌尿系结石标本进行成分分析,并对结果进行比较。结果：泌尿系结石男性发病多于女性,男、女患者比为1．7：1,上尿路结石明显多于下尿路结石,上、下尿路结石例数比为8．9：1。本地区泌尿系结石成分以混合结石为主,共56例,占62．92％,其中碳酸磷灰石与草酸钙混合结石所占比例最大。单纯成分结石共33例,所占比例为37．08％,其中以草酸钙结石为主。结论：根据结石成分分析得到的结石成分特点,对患者饮食、生活习惯等方面进行指导,以预防泌尿系结石的复发。     

Outcomes of urethral calculi patients in an endemic region and an undiagnosed primary fossa navicularis calculus

Urethral calculus is a rare form of urolithiasis with an incidence lower than 0.3%. We determined the outcomes of 15 patients with urethral stone, of which 8 were pediatric, including an undiagnosed primary fossa navicularis calculus. Fifteen consecutive male patients, of whom eight were children, with urethral calculi were assessed between 2000 and 2005 with a mean of 19 months’ follow-up. All stones were fusiform in shape and solitary. Acute urinary retention, interrupted or weak stream, pain (penile, urethral, perineal) and gross hematuria were the main presenting symptoms in 7 (46.7%), 4 (26.7%), 3 (20%) and 1 (6.6%) patient, respectively. Six of them had accompanying urethral pathologies such as stenosis (primary or with hypospadias) and diverticulum. Two patients were associated with upper urinary tract calculi but none of them secondary to bladder calculi. A 50-year-old patient with a primary urethral stone disease had urethral meatal stenosis accompanied by lifelong lower urinary tract symptoms. Unlike the past reports, urethral stones secondary to bladder calculi were decreasing, especially in the pediatric population. However, the pediatric patients in their first decade are still under risk secondary to the upper urinary tract calculi or the primary ones.     

Clinical studies on thirty-two cases of childhood urolithiasis

We evaluated 32 patients with urinary calculi under 16 years of age over the past 14 years since the founding of the Department of Urology, Kinki University School of Medicine. They comprised 0.8% of the total urolithiasis patients. They consisted of 18 boys and 14 girls with a male-to-female ratio of 1.29. The average age was 8.7 years for boys and 10.4 years for girls without any marked peak. The most frequently chief complaint was hematuria which was present in 15 cases (47%). Although pyuria was seen in seven cases (22%), urinary bacterial culture was positive only in 5. The underlying diseases could be diagnosed in 13 cases (41%), of which eight cases (62%) developed metabolic disorder. The sites of calculi were determined in 29 cases (91%), of which 28 had stones in the upper urinary tract. Surgical treatment was performed on 16 cases in 17 sessions. Ureterolithotomy was done in as many as five cases, followed by pyeloplasty in four cases. Nephrectomy was performed in only one case. There was only one case which had been treated with extracorporeal shock-wave lithotripsy (ESWL). The composition of calculi was found in 21 cases (66%), the majority or 13 cases (57%) of which had calcium-containing stones. Nevertheless, there was no case of hypercalciuria. When compared to the previous reports in Japan, it was worthy of note that calculi in the upper urinary tract and calcium-containing stones had higher incidences. It is expected that more patients will be treated with ESWL in the future.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.