A PROSPECTIVE STUDY OF RECURRENCE RATE AND RISK FACTORS FOR RECURRENCE AFTER A FIRST RENAL STONE

PURPOSE: We investigate further the recurrence rate and risk factors for recurrence in 300 consecutive patients who presented to our stone clinic after a first stone episode 7 to 17 years ago. MATERIALS AND METHODS: The medical records of the patients who presented consecutively with a first stone episode from 1980 to 1990 were studied and supplemented by a followup mail questionnaire and telephone interviews. At first visit serum samples were taken from all patients and 24-hour urine samples were collected for metabolic testing. RESULTS: A total of 195 patients were followed successfully, of whom 52 (27%) experienced symptomatic stone recurrence after a mean plus or minus standard deviation of 7.5+/-5.9 years. However, ultrasound examination of 36 symptom-free patients showed recurrent stones in 28%. Comparison of patients with or without recurrence confirmed that recurrence was not influenced by sex, family history of stones and urinary risk factors. However, age at onset of the disease was lower for patients who had 2 or more stones during followup than those who had only 1 stone or no recurrence. CONCLUSIONS: Stones can recur as long as 10 years after the first episode, although the rate is lower than previously reported. The metabolic evaluation after a first stone episode needs to be reappraised in terms of its cost-effectiveness, since recurrences do not seem to be predictable from standard laboratory tests.     

Patients’ attitudes on how to deal with the risk of future stone recurrences

One hundred consecutive patients referred for active stone removal responded to a number of questions regarding their attitude to metabolic risk evaluation and recurrence prevention. Of the 74 men and 26 women all but one were interested in the cause of their disease. While 95% of the patients were motivated to change their dietary habits, only 71% were interested in pharmacological treatment. Collection of 24-h urine for risk evaluation in one or five fractions was acceptable to 94 and 84% of the patients, respectively. Only 79% wanted to collect urine during more than one 24-h period. Given the option of a recurrence prevention programme or active stone removal when or if a stone appeared, approximately half of our patients (52%) chose the first, and about one-third (29%) of them chose the second alternative, whereas as many as 19% of the patients did not express any opinion. A programme for regular follow-up in order to detect new stones early was appreciated by only 81 patients. These results show that biochemical risk evaluation and recurrence prevention is generally met with a positive attitude by most patients and that medical recurrence prevention appears to be appreciated by more than half of the patients.     

Allopurinol treatment of renal calcium stone disease

Thirty-one calcium stone patients were treated with 300 mg allopurinol daily during a mean follow-up period of 2 years. They were also given advice on diet and fluid intake. The effects on the recurrence rate of stones were compared with the effects on the recurrence rate in 43 calcium stone patients who were given similar advice on diet and fluid intake but were not treated with allopurinol. In both groups there was a reduction in the recurrence rate but no difference between patients treated with allopurinol and the control group. Some patients with only hyperuricosuria prior to treatment seemed to benefit from allopurinol treatment, whereas those with hypercalciuria continued to form stones with the same frequency. Allopurinol treatment in calcium stone disease appears less effective than treatment with thiazides, magnesium hydroxide or orthophosphate.     

Does a slower treatment rate impact the efficacy of extracorporeal shock wave lithotripsy for solitary kidney or ureteral stones?

PURPOSE: We compared the efficacy of an SR (70 to 80 shocks per minute) and an FR (120 shocks per minute) for ESWL for solitary stones less than 2 cm located in the kidney or proximal ureter. MATERIALS AND METHODS: A total of 349 patients with a solitary, radiopaque kidney or ureteral stone underwent ESWL on a DoLi(R) 50 lithotriptor. Patients were grouped based on stone size, stone location and whether SR or FR treatment was performed. Of the 349 patients 135 had a renal stone between 1and 2 cm, 137 had a renal stone less than 1 cm and 77 had a proximal ureteral stone with a surface area of between 30 and 90 mm. SFRs were determined at approximately 1 month by plain x-ray of the kidneys, ureters and bladder. RESULTS: In comparison to the FR groups SR groups required fewer shocks and had significantly lower power indexes. Of patients with renal stones between 1 and 2 cm 24 of 52 (46%) in the FR group were stone-free compared to 56 of 83 (67%) in the SR group (p <0.05). For stones with a surface area of 30 to 90 mm located in the kidney or proximal ureter there was a trend toward an improved SFR in the SR group but differences between the SR and FR groups were not statistically significant. CONCLUSIONS: For solitary renal stones between 1 and 2 cm an SR results in a better treatment outcome than an FR for ESWL. However, when stone size is less than 1 cm, SFR differences in the SR and FR treatment groups become less significant.     

A study of allopurinol in the prevention of recurrent calcium oxalate stones

We studied the effect of allopurinol on the prevention of stone recurrence in 134 patients with recurrent, idiopathic calcium nephrolithiasis. They consisted of 113 male patients and 21 female, between 16 and 72 years with an average age of 42.7. The patients were divided into two groups according to the type of stone occurrence; those with multiple stones without previous stone episodes (multiple stone group), and the those with recurrent stones (stone episode group). Twenty three patients belonged to the multiple stone group and 111 patients belonged to the stone episode group. The stones in 19 of the 23 patients in the multiple stone group remained stable throughout the study, while stones in 4 grew. Fifty-nine of the 111 patients in the stone episode group were free from recurrence, but the others showed recurrence. Statistical analyses was done on the stone episode group. The stone recurrence rate of all of the 111 cases showed significant decrease during prophylactic treatment with allopurinol (p less than 0.01), although the observation period before treatment was 73.0 +/- 65.8 months and that during and after treatment was 28.2 +/- 12.1 months. During the two years before and after prophylaxis 79 patients also showed a significantly decreased recurrence rate. Moreover, regarding 37 cases without any stones at the start of treatment, stone recurrence rate decreased significantly after the administration of allopurinol. Throughout this study, we used a new method for evaluating reasonable stone recurrence. It did not calculate the number of stones recurred, but the stone-forming circumstance in each kidney.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of stone analysis in metabolic evaluation and medical treatment of nephrolithiasis

BACKGROUND AND PURPOSE: Comprehensive metabolic evaluation has become an important aspect of the management of recurrent nephrolithiasis, yet the role of stone analysis is often neglected or perhaps underestimated. The purpose of this study was to determine the role of stone analysis in medical decision making in patients with recurrent nephrolithiasis. MATERIALS AND METHODS: We evaluated 100 consecutive stone-forming patients who had undergone compositional stone analysis as well as comprehensive metabolic evaluation at our institution. An analysis of stone composition in relation to metabolic disturbances was performed. Patients were stratified into two groups: calcium and non-calcium stone formers. RESULTS: Patients having non-calcium stones were found to have a metabolic analysis reflecting specific metabolic disorders. Alternatively, patients with calcium stones were heterogeneous with regard to metabolic disorders, but there was a significant likelihood of renal tubular acidosis in those patients with calcium phosphate calculi. On the basis of these results, a simplified metabolic evaluation and nonselective medical therapy based on stone composition was formulated to facilitate assessment, management, and monitoring of stone disease. CONCLUSIONS: Compositional stone analysis should be an integral part of the metabolic evaluation of patients with nephrolithiasis. Moreover, stone analysis alone may provide guidance for therapeutic treatment and obviate a formal metabolic evaluation.     

Dietary recommendations and treatment of patients with recurrent idiopathic calcium stone disease

This review describes the various dietary regimens that have been used to advise patients on how to prevent the recurrence of their calcium-containing kidney stones. The conclusion is that although there is some general advice that may be useful to many patients, it is more efficacious to screen each patient individually to identify his/her main urinary, metabolic, nutritional, environmental, and lifestyle risk factors for stone-formation and then tailor specific advice for that particular patient based on the findings from these investigations. If the patient can be motivated to adhere strictly to this conservative approach to the prophylactic management of their stone problem over a long time period, then it is possible to prevent them from forming further stones. This approach to stone management is considerably less expensive than any of the procedures currently available for stone removal or disintegration. In the UK, for each new stone episode prevented by this conservative approach to prophylaxis it is calculated to save the Health Authority concerned around £2000 for every patient treated successfully. In the long term, this accumulates to a major saving within each hospital budget if most stone patients can be prevented from forming further stones and when the savings are totalled up country-wide saves the National Exchequer considerable sums in unclaimed Sick Pay and industry a significant number of manpower days which would otherwise be lost from work. It is also of immense relief and benefit to the patients not to have to suffer the discomfort and inconvenience of further stone episodes.     

Medical management for the prevention of the recurrence of urolithiasis--with special recurrence to the patients who underwent percutaneous nephrolithotripsy (PNL) or extracorporeal shock wave lithotripsy (ESWL)

Questionnaires about stone recurrence after treatment with percutaneous nephrolithotripsy (PNL) or extracorporeal shock wave lithotripsy (ESWL) were sent to 11 hospitals in the central section of Japan. We received 255 replies on PNL cases and 157 replies on ESWL cases. These patients were evaluated for the recurrence of renal stones and the enlargement of residual stone fragments. The effect of the medical management for the prevention of recurrent stone disease on postoperative recurrence rate was also evaluated. The average follow-up period of patients treated with PNL was 21.6 months, and 18.5 months for patients treated with ESWL. In patients who underwent PNL, 25 of 162 patients (15.4%) who were treated completely without any residual stones have suffered from new stones. The residual stone or fragments enlarged in 14 of the 93 patients (15.1%) who had residual stones or fragments after the treatment. The recurrence rate was significantly higher for the recurrent stone former than the single stone former. The recurrence rate for the patients who had multiple stones, staghorn calculi and metabolic disorders such as hypercalciuria also had a high incidence. Patients who received medical treatment for the prevention of stone recurrence had a lower recurrence rate than the group not treated. Especially among the patients with hypercalciuria, the recurrence rate of stone disease in the treatment group was significantly lower than that in the group not treated.(ABSTRACT TRUNCATED AT 250 WORDS)     

Metabolic risk factors and the impact of medical therapy on the management of nephrolithiasis in obese patients

PURPOSE: Previous studies have demonstrated that obesity can increase the risk of stone formation as well as recurrence rates of stone disease. Yet appropriate medical management can significantly decrease the risk of recurrent stone disease. Therefore, we analyzed our obese patient population, assessing the risk factors for stone formation and the impact of selective medical therapy on recurrent stone formation. MATERIALS AND METHODS: A retrospective chart review was performed to identify obese patients with stone disease from our Stone Center. Metabolic risk factors for stones were identified as well as patient response to medical therapy. A similar analysis was performed on a group of age and sex matched nonobese stone formers. RESULTS: Of 1,021 patients 140 (14%) were identified as obese (body mass index greater than 30). Of these patients complete metabolic evaluations were available in 83 with an average followup of 2.3 years. The most common presenting metabolic abnormalities among these obese patients included gouty diathesis (54%), hypocitraturia (54%) and hyperuricosuria (43%), which presented at levels that were significantly higher than those of the nonobese stone formers (p <0.05). Stone analysis was available in 32 obese patients with 63% having uric acid calculi. After initiating treatment with selective medical therapy obese and nonobese patients demonstrated normalization of metabolic abnormalities, resulting in an average decrease in new stone formation from 1.75 to 0.15 new stones formed per patient per year in both groups. CONCLUSIONS: Obesity, as a result of dietary indiscretion, probable purine gluttony and possible type II diabetes, appears to have a significant role in recurrent stone formation. Appropriate metabolic evaluation, institution of medical therapy and dietary recommendations to decrease animal protein intake can significantly improve the risk of recurrent stone formation in these often difficult to treat patients.     

Outcome and safety of extracorporeal shock wave lithotripsy as first-line therapy of lower pole nephrolithiasis

INTRODUCTION: The aim of this study is to assess the efficiency of extracorporeal shock wave lithotripsy (ESWL) as initial therapy for isolated lower pole kidney stones smaller than 20 mm. PATIENTS AND METHODS: During a 24-month period 116 patients with previously untreated single stones under 20 mm in diameter were treated with a Dornier lithotripter S. They were analyzed with regard to stone site and size, number of ESWL sessions, auxiliary measures, retreatment rates, complications and the time taken for stone clearance. RESULTS: 76 patients (65.5%) became stone free, 50 of them (43.1%) within 3 months after ESWL. Depending on stone size the stone-free rates were 67.1% for patients with a stone diameter of <10 mm (59 of 88 patients), and 60.7% for stone diameters between 10 and 20 mm (17 of 28 patients). Complications during and after treatment were rare, i.e. the necessity of ureteral stent insertion due to colic (n = 10), endoscopic stone removal (n = 2), acute pyelonephritis (n = 1), stonestreet (n = 1) and 1 case of hematoma not requiring intervention. The recurrence rate during follow-up (13.2-36.9, mean 25.0 months) was low: 16 patients (13.8%) had recurrent or persistent stones, and 74 patients (63.8%) had no evidence of urolithiasis. CONCLUSIONS: ESWL is a safe and efficient first-line therapy for treatment of isolated small lower pole kidney stones with acceptable stone-free rates, low morbidity, few complications and a low stone recurrence rate.     

Risk factors determining active urinary stone formation in patients with urolithiasis

AIMS: The goal of clinical and metabolic evaluation of patients with urinary stones is to identify patients at high risk for recurrent stone formation and as such, to allow the practitioner to suggest preventive therapies. However, knowledge about risk factors for active stone formation in patients with urolithiasis is limited. This study was initiated to assess the significance of several metabolic and clinical parameters for the determination of the risk of active stone formation. METHODS: Study in 320 consecutive outpatients referred to our clinic for metabolic analysis. Clinical and metabolic parameters were determined by standardized procedures of questionnaires, serum biochemical profiles and urinalysis. RESULTS: In 21.5% of 284 patients with complete data stone formation was active. Hypercalciuria, hypocitraturia and urinary tract infections had odds ratios for active stone formation above 2.5, whereas the odds ratio of a positive family history was 0.38. Hyperuricosuria, hyperoxaluria and a low urinary volume did not influence the risk for active stone formation. CONCLUSION: The risk profile for active stone formation differs from the risk profile for urolithiasis in general. Metabolic evaluation and determination of those risk factors in patients with urolithiasis might improve the estimation of the risk of future 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.     

INDINAVIR UROLITHIASIS: AN EMERGING CAUSE OF RENAL COLIC IN PATIENTS WITH HUMAN IMMUNODEFICIENCY VIRUS

PURPOSE: We evaluate the clinical, diagnostic and radiographic findings in patients on indinavir therapy who presented with renal colic, and propose appropriate treatment options for indinavir urolithiasis. MATERIALS AND METHODS: A total of 16 patients positive for human immunodeficiency virus on indinavir were evaluated for 18 episodes of severe renal colic requiring hospitalization. Laboratory evaluation was performed in all patients followed by an imaging study. Conservative treatment included intravenous hydration, narcotic analgesics and temporary cessation of indinavir. Intervention was elected only in patients with persistent fever or intractable pain. A month after hospital discharge an excretory urogram and metabolic stone evaluation were performed. Mean followup was 9.3 months and 2 patients had recurrent symptoms. RESULTS: All patients presented with nausea or vomiting and hematuria. Imaging studies confirmed obstruction in all patients with 13 radiolucent (indinavir) and 3 radiopaque (calcium oxalate) stones. Patients with radiolucent and radiopaque stones demonstrated significant differences in urinary pH (p = 0.002) and serum creatinine (p = 0.03). Conservative therapy was successful in 11 patients (68.8%) within 48 hours and 4 patients (25%) with radiolucent calculi required endoscopic stenting for persistent fever. Metabolic stone evaluation demonstrated significant hypocitruria (less than 50 mg./24 hours) in all patients with radiolucent calculi. CONCLUSIONS: The urologist should be familiar with this growing cause of renal colic in patients on indinavir therapy. Pure indinavir stones are radiolucent and have a soft, gelatinous endoscopic appearance. Conservative treatment is successful in most patients and if intervention is deemed medically necessary, endoscopic stent placement should be the procedure of choice.     

Urolithiasis im Kindesalter

Urinary stone disease is relatively rare in children with an overall incidence of 1-2 %; however, it is often associated with metabolic abnormalities that may lead to recurrent stone formation. Stone analysis and subsequent metabolic evaluation is therefore mandatory for this high-risk group after the first stone event. The objectives of stone management in children should be complete stone clearance, prevention of stone recurrence, preservation of renal function, control of urinary tract infections, correction of anatomical abnormalities and correction of the underlying metabolic disorders. The full range of minimally invasive procedures is available if active stone removal is necessary. The majority of stones in children can be managed either with extracorporeal shock wave lithotripsy which has a higher efficacy in children than in adults, percutaneous nephrolithotomy, ureterorenoscopy or a combination of these modalities while open or laparoscopic surgery is limited to well-selected cases with underlying anatomical abnormalities.     

Results of urometabolic evaluation in 127 patients with renal calculous disease

One hundred twenty-seven selected stone formers were evaluated. With the simple ambulatory tests proposed by Pak for metabolic screening and a complete urologic evaluation an anomaly was found in more than 90 per cent of the cases. The patients were divided into three groups: (1) patients operated on for staghorn stones; (2) patients with episodes of spontaneous stone eliminations or young people with only one stone episode; and (3) patients operated on for stone disease. No significant differences were noted except for the occurrence of urinary tract infection and for struvite and calcium oxalate occurrence in the different groups. Urinary tract infection combined with a metabolic disorder appear to make the evolution from small kidney stone to staghorn stone a reality.     

Treatment of cystine calculi using intra-urologic methods and extracorporeal lithotripsy

The hardness and frequent recurrence of cystine stones represent a special challenge for the urologist. Fifteen cystinuric patients were treated in our department and followed over a mean period of 30 months. Most patients had a previous history of open surgery (1.5 pyelolithotomy/patient). Diagnosis of cystinuria was confirmed by metabolic studies and stone analysis. Over the follow-up period recurrence was observed in 23 instances in 11 patients thus leading to 38 stone treatments on 74 cystine stones. Stone size was less than 10 mm: 35 (47%); 10-20 mm: 21 (28%); 20-30 mm: 14 (19%); 30 mm: 4 (staghorn stones). A percutaneous approach was used in 9 cases as monotherapy (55% success) and in association with ESWL in 10 cases (50% success). ESWL was employed 18 times as monotherapy (39% success). Medical treatment included high fluid intake, alkalinisation and thiola in 6 patients. In conclusion, results obtained are poor in terms of stone clearance when compared to non-cystine stones. Recurrence rate is very high. Instrumental treatment should not be used excessively and is only indicated in symptomatic stones or refractory to intensive medical therapy.     

Guidelines on urolithiasis.

OBJECTIVES: A project was initiated by the Health Care Office of the European Association of Urology in order to formulate common recommendations and guidelines for the treatment of patients with urolithiasis. The basic task for the working group therefore was to extract and evaluate evidence from the literature in order to reach a consensus on how these patients could best be managed. METHODS: Extensive reviews of the literature together with a thorough and detailed discussion of the various topics, by a working group including of experts from several European countries, provided the basis for a consensus overview of urolithiasis and its management. RESULTS AND CONCLUSIONS: Recommendations are given for the management of patients with acute stone colic and for active removal of stones from the ureter and kidney. Moreover, the principles for risk evaluation of patients with recurrent stone formation and appropriate recurrence preventive treatment are given.     

A prospective study of nonmedical prophylaxis after a first kidney stone.

OBJECTIVE: To assess, in a multicentre prospective randomized study, the effectiveness of specific nonmedical prophylaxis and nonspecific dietary prophylaxis in patients treated after experiencing their first idiopathic calcium-containing kidney stone. PATIENTS AND METHODS: From 1991 to 1994, 242 patients with idiopathic calcium urinary stones from three urological centres were randomly assigned into two groups. In group 1 (intervention, 113 patients), a specific dietary regimen was recommended and thereafter corrected according to a comprehensive metabolic evaluation. Group 2 (control, 94 patients) underwent only minimal metabolic screening and used general dietary measures, with no regular follow-up. An increased fluid intake was recommended in both groups. After 3 years, the effectiveness of the prophylactic and dietary regimens was evaluated in 207 patients. RESULTS: At entry, the clinical characteristics were comparable in the two groups, with only extracorporeal lithotripsy being more frequent in group 2. Almost 80% of patients reported a high intake of meat and a low intake of dairy products. In group 1 and 2, a recurrent stone was encountered in seven (6%) and 18 (19%) patients, respectively; recurrent and growing stones were found in eight (8%) and 22 (23%) patients, respectively (P<0. 01). There was a higher incidence of bilateral residual (or untreated) stones, and Weddellite stones (P<0.001) among patients with a recurrent or growing stone. An analysis of the dynamics of the metabolic variables indicated the significance of repeated dietary counselling. CONCLUSION: Specific dietary therapy, adjusted according to a metabolic evaluation, is more effective than nonspecific general dietary recommendations in preventing the formation of a second urinary stone.     

Nephrolithiasis in children

A metabolic etiology is the most common cause for pediatric kidney stones. Appropriate evaluation of affected children should include assessment of stone type, if available, and assessment of predisposing factors in all cases. This review discusses the metabolic disorders that lead to nephrolithiasis with respect to the development of calcium, uric acid, struvite, and cystine stones. Environmental and hereditary factors are summarized to provide a guide in the evaluation of pediatric stone formers.     

Effect of potassium citrate therapy on stone recurrence and regrowth after extracorporeal shockwave lithotripsy in children

BACKGROUND AND PURPOSE: Stone disease in children may cause functional and morphologic changes in the urinary tract during longer-term follow-up. Prevention of stone recurrence will be possible only with careful metabolic evaluation and appropriate management. The possible preventive effects of potassium citrate therapy on true stone recurrence, as well as regrowth rates after shockwave lithotripsy (SWL), were evaluated in children treated for renal stones. PATIENTS AND METHODS: Following assessment of the efficacy of SWL, 96 children (72 male, 53 female aged 4 to 14 years with a mean of 6.6 years) were evaluated for the effects of potassium citrate on residual fragments as well as true new stone formation during long-term follow-up. All children had calcium-containing stones with normal renal morphology and function without any urinary-tract infection. Depending on the outcome of treatment, patients with and without residual stones were allocated independently to Group I (N = 52) and Group II (N = 44), which were matched for sex and age. Group I was given oral potassium citrate 1 mEq/kg daily for 12 months; the remaining children served as controls. Follow-up ranged from 12 to 36.6 months, with a mean of 24.4 months. Follow-up results for at least a year with respect to the stone recurrence or stone growth rates were recorded in both groups. RESULTS: Stone-free children undergoing no specific therapy had significant new stone formation compared with the group receiving potassium citrate on a regular basis (34.6% and 7.6%, respectively). Children with residual fragments receiving no specific preventive measure also showed significant new stone formation, along with enlargement of the fragments. CONCLUSION: In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic evaluation. Depending on the abnormalities, each patient should be advised on adequate drinking to increase the urine volume in accordance with body size. Although children with hypocitraturia may well benefit from therapeutic agents that raise the urine citrate concentration, our results did clearly show that all children bearing residual fragments should be counseled on adequate fluid intake along potassium citrate treatment to prevent stone regrowth or formation during long-term follow-up.