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.     

Bacteriology of upper urinary tract stones

Extensive cultures of stones and urine were performed in 215 patients who underwent an operation for upper urinary tract calculi. Microorganisms could be cultured from the stone in 1 of every 3 patients. Despite the extended culture technique urease-producing microorganisms could be cultured from the stone in only 48% of the patients with calculi that contained magnesium ammonium phosphate. This finding suggests that an infection with urease-producing microorganisms is not obligatory for the formation of this type of stone. Of the patients with calcium oxalate phosphate stones 32% had positive stone cultures, which distinguished them from patients with pure calcium oxalate stones, only 8% of whom had a positive stone culture (p less than 0.001).     

Renal stones in children in Pakistan

One hundred and fifty children up to the age of 12 years with documented evidence of renal or ureteric stones were studied between July 1973 and June 1983. The peak age group was between 10 and 12 years, the male to female ratio being 1.9:1. Abdominal pain was the commonest presenting symptom (66.6%). Asymptomatic stones or vague symptoms in 23 patients warrant a higher index of suspicion of renal stone disease in children. Thirty patients had associated renal insufficiency. One third of the children had a positive urine culture, Proteus spp. being the commonest organism. Congenital anomalies of the urinary tract were seen in 12% of patients. In the majority (59%), aetiological factors related to stone formation could not be identified. One hundred and thirty patients underwent surgery for removal of stones. Analysis of calculi by X-ray diffraction and infrared spectroscopy revealed that stones were predominantly of mixed type, calcium oxalate being the commonest compound. The overall recurrence rate following surgical removal was 15%.     

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.     

复杂性肾结石的早期诊断及预防

目的通过分析复杂性肾结石病史,结石成分等临床特点,为其诊疗及预防提供帮助。方法回顾性研究2009年8月至2010年5月于北京大学人民医院进修期间118例复杂性肾结石病例,对患者病史、既往史、结石化学成分及尿常规、肾功能等临床资料进行总结分析。结果118例患者中,7例(5.9%)接受过定期规律体检,97例(82.2%)从未曾接受过健康体检,64例(54.2%)曾有结石病史,86例(72.9%)以疼痛、血尿及发热等不适症状为主诉,92例(78.0%)伴有泌尿系感染,18例(15.3%)伴有肾功能不全,结石成分中含钙结石94例(79.7%),感染石55例(46.6%),含尿酸结石28例(23.7%)。结石以混合成分为主,其中感染石与草酸钙的混合成分所占比例最大,共51例(43.2%)。结论应通过定期规律体检提高早期诊断比例,控制结石进展,根据不同结石成分,采取有针对性的预防措施,同时必须重视抗感染治疗,以减少患者损伤,降低结石复发率。     

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.     

Kidney stones during pregnancy: an investigation into stone composition

Kidney stones can be a source of considerable morbidity for pregnant women. Although there is a body of literature confirming that different stone compositions predominate for different age and sex cohorts, there have been no similar reports characterizing the nature of stone disease during pregnancy. We performed a multi-institutional study to define the composition of renal calculi diagnosed during pregnancy. We retrospectively reviewed the records from two stone referral centers of all patients diagnosed with a de novo kidney stone during pregnancy who underwent a procedure for the purpose of stone removal from June 2001 through September 2007. A total of 27 patients were identified, with a mean age of 26.8 years (range, 21-34). Twenty patients (74%) had no history of prior stone formation. Seven patients (26%) had previously formed stones, although none of these patients had a known kidney stone at the time they became pregnant. Stones were removed in the first, second, third trimester and immediately post-partum in 4, 52, 22, and 22% respectively. Stone removal was performed without complication in all cases. Analysis found that in 74% of all cases (20 patients) stones were composed predominantly of calcium phosphate (hydroxyapatite). In 26% of cases, (7 patients) the stones were composed predominantly of calcium oxalate. Of the seven patients with prior stone history, three patients had previously formed calcium phosphate stones and four patients had previously formed calcium oxalate stones. Calcium oxalate calculi are the most common stone in non-pregnant women of a comparable age as our subjects. However, our present data suggest that stones detected during pregnancy are most commonly composed of calcium phosphate (hydroxyapatite). Indeed, it is the minority of stones that are composed of calcium oxalate. Although the reason for this unusual preponderance of calcium phosphate calculi is unclear, physiologic alterations that occur during pregnancy may be influential.     

The severity of infection stones compared to other stones in the upper urinary tract

A retrospective study of the case records of 391 adult patients with spontaneously passed or surgically removed concrements from the upper urinary tract during the period 1982-1983 was performed. According to chemical analysis, 66% of the stones were calcium stones, 30% were infection stones, 4% were uric acid/urate stones and 1% were cystine stones. Of the infection stones 12 (10%) were staghorn calculi. The infection stones placed a greater strain on the patients than the calcium stones. Thus, infection stones were significantly more often recurrent stones and required surgery significantly more often than the calcium stones. Only 6% of the patients with infection stones had proved abnormalities predisposing to upper urinary tract infection. Urinary tract infection with a urease-producing microorganism was detected in only 52% of the patients with infection stones. As infection with a urease-producing microorganism is a prerequisite for the formation of infection stones in the urinary tract a careful microbiological investigation to find and treat the infection responsible for the stone formation is mandatory.     

Efficacy of percutaneous treatment of biliary tract calculi using the holmium:YAG laser

Background Few Western studies have focused on percutaneous techniques using percutaneous transhepatic choledochoscopy (PTHC) and holmium:yttrium–aluminum–garnet (YAG) laser to ablate biliary calculi in patients unable or unwilling to undergo endoscopic or surgical removal of the calculi. The authors report the efficacy of the holmium:YAG laser in clearing complex biliary calculi using percutaneous access techniques. Methods This study retrospectively reviewed 13 non-Asian patients with complex secondary biliary calculi treated percutaneously using holmium:YAG laser. Percutaneous access was accomplished via left, right, or bilateral hepatic ducts and upsized for passage of a 7-Fr video choledochoscope. Lithotripsy was performed under choledochoscopic vision using a holmium:YAG laser with 200- or 365-μm fibers generating 0.6 to 1.0 joules at 8 to 15 Hz. Patients underwent treatment until stone clearance was confirmed by PTHC. Downsizing and subsequent removal of percutaneous catheters completed the treatment course. Results Seven men and six women with an average age of 69 years underwent treatment. All the patients had their biliary tract stones cleared successfully. Of the 13 patients, 3 were treated solely as outpatients. The average length of percutaneous access was 108 days. At this writing, one patient still has a catheter in place. The average number of holmium:YAG laser treatments required for stone clearance was 1.6, with no patients requiring more than 3 treatments. Of the 13 patients, 8 underwent a single holmium:YAG laser treatment to clear their calculi. Prior unsuccessful attempts at endoscopic removal of the calculi had been experienced by 7 of the 13 patients. Five patients underwent percutaneous access and subsequent stone removal as their sole therapy for biliary stones. Five patients were cleared of their calculi after percutaneous laser ablation of large stones and percutaneous basket retrieval of the remaining stone fragments. There was one complication of pain requiring admission, and no deaths. Conclusions The use of PTHC with holmium:YAG laser ablation is safe and efficacious, but requires prolonged biliary access and often multiple procedures to ensure clearance of all calculi.     

Clinical patterns of paediatric urolithiasis

A series of 270 paediatric stone patients was studied retrospectively according to the clinical pattern of urolithiasis (age and sex, stone location, stone analysis, recurrence rate) and aetiology of stone disease (infection, anatomical, metabolic or idiopathic). Infection stones occurred earliest and more commonly in males and were usually upper tract struvite calculi related to Proteus infection. Anatomical stones were most commonly associated with pelviureteric junction (PUJ) obstruction and had a high recurrence rate, despite surgical correction of obstruction. Idiopathic stones most resembled those found in adult urolithiasis by virtue of occurring latest, being sited in the ureter more often and being more frequently composed of calcium oxalate. Metabolic stones were most frequently calcium phosphate or cystine and virtually all were renal. They comprised the smallest group but had the highest recurrence rate.     

Spectrum of stone composition: structural analysis of 1050 upper urinary tract calculi from northern India

BACKGROUND: The purpose of the present paper was to study the spectrum of stone composition of upper urinary tract calculi by X-ray diffraction crystallography technique, in patients managed at All India Institute of Medical Sciences. METHODS: Between 30 April 1998 and 31 March 2003, a total of 1050 urinary calculi (900 renal, 150 ureteric) were analyzed. The stone fragments were collected after extracorporeal shock-wave lithotripsy, or retrieval by endoscopic (percutaneous nephrolithotomy, ureterorenoscopy), laparoscopic and various open surgical procedures. The structural analysis of the stones was done using X-ray diffraction crystallography. RESULTS: Four types of primary and three secondary X-ray diffraction patterns were obtained. The primary patterns were as follows. Pattern A, well organized crystalline structure; pattern B, moderately organized crystalline structure; pattern C, poorly organized crystalline structure; pattern D, very poorly organized crystalline structure. The three secondary patterns mainly highlighted the mixed variety of stones. These patterns were further analyzed and compared with standard X-ray diffraction (powder) photographs. Of the 1050 stones analyzed, 977 (93.04%) were calcium oxalate stones, out of which 80% were calcium oxalate monohydrate (COM) and 20% were calcium oxalate dihydrate (COD). Fifteen were struvite (1.42%) and 19 were apatite (1.80%). Ten were uric acid stones (0.95%) and the remaining 29 (2.76%) were mixed stones (COM + COD and calcium oxalate + uric acid, calcium oxalate + calcium phosphate, and calcium phosphate + magnesium ammonium phosphate). A total of 89.98% of staghorn stones were made of oxalates (COM/+COD) and only 4.02% were struvite. CONCLUSION: Urinary stone disease in the Indian population is different from that in Western countries, with a larger percentage of patients having calcium oxalate stones, predominantly COM. Also, the majority of staghorn stones (89.98%) were made of oxalates.     

Combined fluoroendoscopic removal of retained biliary stones

Sixty-one patients were referred in the postoperative period for stone extraction through the T-tube tract. In four patients the calculi passed spontaneously. One patient had a papilloma and another a blood clot mimicking a stone. Of the remaining 55 cases, all but three were successfully treated by removal of all calculi from the ductal system, a success rate of 94.5%. No major complications occurred in this series. We believe the combined fluoroendoscopic approach to be the preferred method of extracting stones through the T-tube tract because of the greater precision possible when manipulating under direct vision and the reduction in radiation exposure of patients and personnel.     

Endoscopic sphincterotomy for common bile duct calculi

A series of 74 patients having endoscopic sphincterotomy for common bile duct calculi is reported. Complete stone extraction was achieved in 53 cases (72%). Seventeen of 21 patients with retained calculi following recent biliary surgery had successful extractions (80%). Of 30 patients having had a cholecystectomy, 21 (70%) were successful, but only 15 of 23 patients with obstructive jaundice and no previous biliary surgery had the ducts cleared of calculi. Failure was due to multiple stones in the duct, or calculi too large to pass through the sphincterotomy. Endoscopic sphincterotomy is advocated in patients with obstructive jaundice due to stones, moving to early surgery should it prove unsuccessful. The results in patients with a T-tube in situ are comparable to extraction of the calculi along the T-tube tract.     

Paediatric urolithiasis in Greece

A group of 44 patients, aged from 10 months to 14 years, underwent surgery for urinary calculi over a 7-year period (1982-1989). Eleven patients had bilateral or multiple calculi (total number of stones = 55, 20 of which were staghorn). Metabolic disorders (n = 25) and Proteus urinary infection (n = 15) were the 2 factors most often associated with lithiasis. Of the 55 stones, 51 were removed by open surgery. Complete stone clearance was achieved in 29 of 36 kidneys. Follow-up periods in the remaining 7 renal units (with small residual fragments) ranged from 3.5 to 7.5 years (mean 6.2) and revealed stone recurrence in only 2 patients. Evaluation of childhood urolithiasis should include thorough metabolic investigation and sound surgical judgment; effective management requires prolonged post-operative follow-up.     

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.     

Ureteral calculi in children: review of 50 consecutive cases

Fifty children presenting with ureteral calculi over a twenty-year period were studied retrospectively. There were 35 boys and 15 girls, with a mean age of five and a half years. Nineteen patients had a urinary tract anomaly: 11 had an obstructed megaureter, and 8 had previously undergone urinary tract surgery. Forty-four children had infection stones and the remaining 6 oxalate calculi. Infected urine was found in 35; the infecting organism was a Proteus species in 23. Metabolic abnormalities were detected in 2 children. Operative removal of the stones was done in 39 patients, and in the remaining 11 patients the stones passed spontaneously. There were 6 recurrences, all within four years of initial presentation.     

Treatment of ureteral stone disease: the role of ESWL and endourology

Summary In recent years, extracorporeal shockwave lithotripsy (ESWL) has proved a safe and easily reproducible method for the treatment of calculi in the upper urinary tract above the iliac crest. Current indications for ESWL as single therapy encompass approximately 60%–70% of all stones. The use of endourological methods as auxiliary procedures can enhance the range of indications to 95% of all renal stones and 85% of all ureteral stones. In the last year, 1340 patients have been successfully treated for urinary calculi at our department. Evaluation of all stone cases shows that ESWL alone, ESWL combined with percutaneous techniques, or percutaneous techniques alone were performed on 93% of all patients. Only 7% of patients had to undergo open surgical treatment, 1% for renal stones and 15% for ureteral stones. Ureteral stones are still among the problem stones for ESWL, in many cases requiring time-consuming combined procedures with either of the percutaneous methods. Furthermore, ureteral obstruction caused by stone particles as a complication after ESWL-treatment of large renal stones has to be relieved using percutaneous techniques. In this report we describe our approach in detail and discuss our results.     

Long-term followup in patients with cystine urinary calculi treated by percutaneous ultrasonic lithotripsy

From February 1983 through 1986, 15 patients (17 renal units) with cystine urinary lithiasis were treated by percutaneous ultrasonic lithotripsy. Three patients were lost to followup. Of the 13 renal units in the remaining 12 patients 7 (54 per cent) had retained stone fragments and 6 (46 per cent) were free of stones. While on medical management 7 of the 13 renal units (54 per cent) had new stones, 5 (38 per cent) remained unchanged and in 1 (8 per cent) the retained stones dissolved. The rate for reoperations was 43 per cent for the group with retained stones (3 of 7) and 17 per cent for the group that was free of calculi after percutaneous ultrasonic lithotripsy (1 of 6). Our study suggests that the optimal treatment with percutaneous ultrasonic lithotripsy should result in a patient who is free of stones.     

Percutaneous nephrolithotomy for treating renal calculi in children

OBJECTIVE: To report our experience with the percutaneous management of renal stone disease in children. PATIENTS AND METHODS: The medical and radiological records of children up to 18 years old who were treated for renal calculi by percutaneous nephrolithotomy (PCNL) at our institution between March 1995 and April 2003 were reviewed. For stone removal a special paediatric 18 F access sheath was used. RESULTS: In all, 26 PCNLs were used in 23 patients (10 boys and 13 girls, aged 1.7-16.8 years). The presenting symptoms were urinary tract infection, abdominal pain and/or haematuria. Of the 23 patients, 17 (75%) had associated metabolic disease or underlying urological anatomical abnormalities. Urinary tract infections were found in 15 patients (65%). The mean (range) stone burden was 6.0 (0.5-18.2) cm2, and the operative duration 127 (50-260) min. The primary stone-free rate was 58%, which increased to 81% after treating residual fragments. One blood transfusion was required and one patient developed urosepsis after PCNL, which was treated with antibiotics. CONCLUSION: PCNL is an effective alternative for treating renal stones in children, and is the treatment of choice for stones refractory to extracorporeal shock wave lithotripsy.     

Formation of the staghorn calculi

To study the process of formation of staghorn calculi, 58 patients with staghorn calculi were evaluated clinically and the removed stones were studied architecturally. Of 35 patients with infection stones composed of struvite and/or apatite in the nuclei as well as peripheral layers, 18 had identified predisposing factors related to infection. Of 13 patients with infection stones containing calcium oxalate in the nuclei, 7 had predisposing factors of infection but only 2 had metabolic disorders. The patients with infection stones who had no predisposing factors may have transient or subclinical abnormalities. Initial stone formation of oxalate may also be one of the predisposing factors of infection. Most of the patients with staghorn calculi composed of uric acid, oxalate and cystine, had metabolic disorders related to these substances. Large numbers of bacteria and large amounts of organic matrix were found extensively within infection stones and were thought to be important components as well as crystals. Metabolic stones contained little matrix. In this case crystal aggregation is thought to play the most important role in stone formation.