Role of combined use of potassium citrate and tamsulosin in the management of uric acid distal ureteral calculi

Prevention, diagnosis, and treatment of urolithiasis in geriatric patients - differences, similarities and caveats in comparison to the general population

PURPOSE OF REVIEW

Purpose of the review is to address management and prevention of urolithiasis in elderly patients examining the dynamic interplay between general measures, dietary adjustments, lifestyle modifications, and targeted pharmacological and/ or surgical interventions. The goal is to provide understanding of the evolving strategies required for effective urolithiasis prevention in the geriatric population.

RECENT FINDINGS

Age-specific diagnostic considerations are necessary because urolithiasis in the elderly population is characterized by bigger stones, greater peri-operative risks, and heightened symptom severity. When comorbidities are present, conservative treatments - especially analgesia - provide difficulties. Surgical procedures prove to be safe and effective, with complication rates and practical application comparable to younger cohorts. Prevention approaches that include lifestyle changes and the investigation of novel pharmaceutical options such as sodium-dependent glucose co-transporter 2 (SGLT-2)-inhibitors are promising in the management of urolithiasis in the elderly population.

SUMMARY

Our review offers a thorough investigation of urolithiasis in the elderly population, elucidating distinct clinical manifestations, complex diagnostic issues, and treatment implications. The safety and effectiveness of ureteroscopy in older patients, as well as the possible prophylactic function of SGLT-2-I, offer crucial insights for clinicians. Subsequent studies are necessary to enhance age-specific therapies, addressing the distinct obstacles presented by urolithiasis in the elderly population within this rapidly growing demographic.

Construction of an alignment diagram model for predicting calculous obstructive pyonephrosis before PNL

Background

To develop a model for the accurate prediction of calculous obstructive pyonephrosis prior to percutaneous nephrolithotomy (PNL), leading to early local anaesthesia microchannel nephrostomy for drainage of pyonephrosis.

Methods

By comparing the differences in baseline clinical indicators between the pyonephrosis group and nonpyonephrosis groups, independent risk factors were screened out, and a diagnostic alignment diagram model for predicting calculus obstructive pyonephrosis before PNL was established.

Results

Multivariate regression analysis showed that preoperative blood neutrophil count (Neu), serum creatinine level (Scr), serum albumin level (Alb), urine nitrite (UN), hydronephrosis density (HD) and fever history within one month (HFWOM) were independent risk factors for calculous obstructive pyonephrosis. The AUC value of the receiver operating characteristic (ROC) curve was 0.929. The calibration curves showed that the predictive model was well corrected and that the predictive model had strong consistency. Decision analysis curves showed good clinical efficacy of the model.

Conclusion

The alignment diagram model accurately predicts patients with preoperative calculous obstructive pyonephrosis in the PNL and provides an evidence-based basis for early renal microchannel nephrostomy.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

A New Parameter for Calcium Oxalate Stones: Impact of Linear Calculus Density on Non-Contrast Computed Tomography

Background and Objectives: Non-contrast computed tomography (NCCT) is widely used to evaluate urolithiasis. The NCCT attenuation, measured in Hounsfield units (HU), has been evaluated to predict stone characteristics. We propose a novel parameter, linear calculus density (LCD), and analyze variables from NCCT imaging to predict calcium oxalate (CaOx) stones, which are common and challenging to fragment. Materials and Methods: We retrospectively reviewed the medical records of patients with urolithiasis between 2014 and 2017. Among those, 790 patients were included. Based on the NCCT pre-treatment, the maximal stone length (MSL), mean stone density (MSD), and stone heterogeneity index (SHI) were obtained. In addition, the variation coefficient of stone density (VCSD = SHI/MSD × 100) and linear calculus density (LCD = VCSD/MSL) were calculated. In accordance with the stone analysis, the patients were divided into two groups (CaOx and non-CaOx groups). The logistic regression model and receiver operating characteristic (ROC) curve were used for predictive modeling. Results: In the CaOx group, the SHI, VCSD, and LCD were more significant than in the non-CaOx group (all p < 0.001). SHI (OR 1.002, 95% CI 1.001-1.004, p < 0.001), VCSD (OR 1.028, 95% CI 1.016-1.041, p < 0.001), and LCD (OR 1.352, 95% CI 1.270-1.444, p < 0.001) were significant independent factors for CaOx stones in the logistic regression models. The areas under the ROC curve for predicting CaOx stones were 0.586 for SHI, 0.66 for VCSD, and 0.739 for LCD, with a cut-point of 2.25. Conclusions: LCD can be a useful new parameter to provide additional information to help discriminate CaOx stones before treatment.

The impact of stenting prior to oral chemolysis of upper urinary tract uric acid stones

PURPOSE

To evaluate the impact of ureteral stenting on the success rate of oral chemolysis in the management of suspected uric acid upper urinary tract (UUT) stones.

METHODS

Retrospective matched-pair analysis of 172 patients treated with oral chemolysis from 01/2010 to 12/2019. Patients with low density (upon non-contrast enhanced computer tomography [NCCT]), radiolucent (on plain radiography) urinary stones, a low urine pH (< 6) and/or history of uric acid urolithiasis were included. Potassium citrate and/or sodium bicarbonate were used for alkalization (target urine pH: 6.5-7.2). Patient 1:1 matching was performed for the presence of indwelling ureteral stent, stone diameter, stone density, and stone localization. Stone-free status was evaluated after 12 weeks using NCCT. Multivariable logistic regression analysis was used to assess factors affecting the outcome.

RESULTS

Mean patient age was 61 years (73% males). Mean stone size was 12 mm. Overall success rates after 12-weeks of chemolysis for stones at any localization in the UUT and ureteral stones were 60.5 and 77.3%, respectively. Smaller stone size (OR = 0.94; CI 0.888-0.992; p = 0.026) and lower pre-treatment urine pH (OR = 0.131; CI 0.023-0.737; p = 0.021) significantly increased the success of oral chemolysis. Ureteral stenting did not have any impact on the efficacy of oral chemolysis.

CONCLUSION

Oral chemolysis is an effective treatment modality for patients with UUT stones suspected of uric acid content irrespective of ureteral stenting. Smaller stone diameter and lower urine pH at diagnosis increase its efficacy.

Comparison of efficacy of various drugs used for medical expulsive therapy for distal ureter stones: A systematic review and network meta-analysis

OBJECTIVES

Medical expulsive therapy has been found to be effective for distal ureteric stones; however, which drug is most efficacious in terms of stone expulsion rate (SER) and stone expulsion time (SET) is not known. With this review we aimed to compare the efficacy of various drug treatments for distal ureter stones used as medical expulsive therapy in terms of SER and SET.

METHODS

Systematic literature search was conducted to include all the randomised study comparing various drug interventions for lower ureter stones. Standard preferred reporting items for systematic review and meta-analysis for network meta-analysis (PRISMA-NMA) were pursued.

RESULTS

In this review, 50 randomised studies with 12,382 patients were included. For stone expulsion rate (SER), compared with placebo all the treatment groups were more effective except nifedipine and sildenafil. According to the SUCRA values obtained, naftopidil plus steroid was the highest rank and nifedipine lowest. For stone expulsion time (SET), compared with placebo only tadalafil plus silodosin, nifedipine plus steroid, alfuzosin, silodosin, tadalafil and tamsulosin were more effective. SUCRA values were highest for tadalafil plus silodosin and least for naftopidil plus steroid. From subgroup analysis with individual drugs for SER, SUCRA values were highest for naftopidil followed by silodosin and SET was highest for silodosin and least for naftopidil.

CONCLUSION

For lower ureter stone, tadalafil plus silodosin is the best combination and silodosin best individual drug considering the SET and SER. Nifedipine as monotherapy is no more effective than control group.

Comparison of efficacy of three commonly used alpha-blockers as medical expulsive therapy for distal ureter stones: A systematic review and network meta-analysis

Introduction:

The efficacy of alpha-blockers as medical expulsive therapy (MET) is well established. However, it is not known which of the three most commonly used alpha-blockers (tamsulosin, alfuzosin and silodosin) is the most efficacious. With this study we aimed to assess the efficacy of the three commonly used alpha-blockers as MET for distal ureter stones.

Materials and Methods:

For this review, we searched multiple databases such as PubMed/Medline, Scopus, Embase, OviD SP, CINAHL, and web of science to identify all the relevant randomized studies comparing the efficacy of tamsulosin, alfuzosin, and silodosin. Preferred reporting items for systematic reviews for network meta-analysis (PRISMA-NMA) were followed while conducting this review and the study protocol was registered with PROSPERO (CRD42020175706).

Results:

In this review, 31 studies with 7077 patients were included. Compared to placebo all the treatment groups were more effective for both stone expulsion rate (SER) and stone expulsion time (SET). For both SER and SET, silodosin had the highest SUCRA (94.8 and 90.4) values followed by alfuzosin (58.8 and 64.9) and tamsulosin (46.2 and 44.5). The incidence of postural hypotension was similar with all the drugs, whereas, the incidence of retrograde ejaculation was significantly higher for silodosin. Overall confidence for each comparison group in this review ranged from “very low” to “moderate” according to the CINeMA approach.

Conclusion:

Among the three commonly used alpha-blockers silodosin is the most efficacious drug as MET for lower ureter stones followed by alfuzosin and tamsulosin.

Oral chemolysis is an effective, non-invasive therapy for urinary stones suspected of uric acid content

Despite the possible benefit from avoiding stone surgery with all its possible complications, oral chemolysis is rarely performed in patients with urinary stones suspected of uric acid content. Among the reasons for its limited use is the sparse and low-quality data on its efficacy and the lack of reliable factors predicting its outcome. We thus performed a retrospective single-center cohort study of 216 patients (median patient age 63 years) with 272 renal (48%) and/or ureteral (52%) stones treated with oral chemolysis from 01/2010 to 12/2019. Patients with low urine pH (< 6), low stone density upon non-contrast enhanced computed tomography (NCCT), radiolucent urinary stones on plain radiography, and/or a history of uric acid urolithiasis were included. Potassium citrate and/or sodium/magnesium bicarbonate were used for alkalization (target urine pH 6.5–7.2). Median stone size was 9 mm, median stone density 430 Hounsfield Units. Patients with ureteral stones < 6 mm were excluded since stones this small are very likely to pass spontaneously. The stone-free status of each patient was evaluated after 3 months using NCCT. Oral chemolysis was effective with a complete and partial response rate of stones at 3 months of 61% and 14%, respectively; 25% of stones could not be dissolved. Lower stone density (OR = 0.997 [CI 0.994–0.999]; p = 0.008) and smaller stone size (OR = 0.959 [CI 0.924–0.995]; p = 0.025) significantly increased the success rate of oral chemolysis in multivariate logistic regression analysis. More precise stone diagnostics to exclude non-uric-acid stones could further improve outcome.

Is tamsulosin effective for the passage of symptomatic ureteral stones: A systematic review and meta-analysis

BACKGROUND

Some trials have stated that there is no benefit to tamsulosin administration for clearing ureteral stones, which is contrary to previous studies. To confirm the efficacy of tamsulosin for treating symptomatic ureteral stones, we performed this review.

METHODS

We searched the PubMed, Embase, and Cochrane Library databases to identify all studied variables, including tamsulosin, urinary stones, expulsion, and side effects. In addition, for all patients and different stone sizes, the treatment efficacy, expulsion rate, and expulsion time were also recorded for this treatment.

RESULTS

Forty-nine studies involving 6436 patients met the inclusion criteria. The data synthesized from these studies indicated that tamsulosin improved the renal stone clearance rate (80.5% vs 70.5%; mean difference (MD), 1.16; 95% confidence interval (CI), 1.13-1.19; P <.00001) and reduced the expulsion time (MD, -3.61; 95% CI, -3.77 to -3.46; P ≤.00001). Regarding complications, no significant difference was found between the 2 groups in terms of the total side effects (MD, 1.15; 95% CI, 0.97-1.35; P = .10) or divided complications, including retrograde ejaculation (P = .01), hypotension (P = .52), dizziness (P = .07), diarrhea (P = .58), vomiting (P = .88), headache (P = .84), nausea (P = .91), and fatigue (P = .10).

CONCLUSIONS

Tamsulosin should be strongly recommended for patients with ureteral stones to increase treatment efficacy. The side effects were not significantly different between the tamsulosin and control treatments.

Alpha-blockers as medical expulsive therapy for ureteral stones

BACKGROUND

Ureteral colic is a common reason for patients to seek medical care. Alpha-blockers are commonly used to improve stone passage through so-called medical expulsive therapy (MET), but their effectiveness remains controversial. This is an update of a 2014 Cochrane review; since that time, several large randomised controlled trials (RCTs) have been reported, making this update relevant.

OBJECTIVES

To assess effects of alpha-blockers compared with standard therapy for ureteral stones 1 cm or smaller confirmed by imaging in adult patients presenting with symptoms of ureteral stone disease.

SEARCH METHODS

On 18 November 2017, we searched CENTRAL, MEDLINE Ovid, and Embase. We also searched ClinicalTrials.gov and the WHO Portal/ICTRP to identify all published/unpublished and ongoing trials. We checked all references of included and review articles and conference proceedings for articles relevant to this review. We sent letters to investigators to request information about unpublished or incomplete studies.

SELECTION CRITERIA

We included RCTs of ureteral stone passage in adult patients that compared alpha-blockers versus standard therapy.

DATA COLLECTION AND ANALYSIS

Two review authors screened studies for inclusion and extracted data using standard methodological procedures. We performed meta-analysis using a random-effects model. Primary outcomes were stone clearance and major adverse events; secondary outcomes were stone expulsion time, number of pain episodes, use of diclofenac, hospitalisation, and surgical intervention. We assessed the quality of evidence on a per-outcome basis using the GRADE approach.

MAIN RESULTS

We included 67 studies with 10,509 participants overall. Of these, 15 studies with 5787 participants used a placebo.Stone clearance: Based on the overall analysis, treatment with an alpha-blocker may result in a large increase in stone clearance (risk ratio (RR) 1.45, 95% confidence interval (CI) 1.36 to 1.55; low-quality evidence). A subset of higher-quality, placebo-controlled trials suggest that the likely effect is probably smaller (RR 1.16, 95% CI 1.07 to 1.25; moderate-quality evidence), corresponding to 116 more (95% CI 51 more to 182 more) stone clearances per 1000 participants.Major adverse events: Based on the overall analysis, treatment with an alpha-blocker may have little effect on major adverse events (RR 1.25, 95% CI 0.80 to 1.96; low-quality evidence). A subset of higher-quality, placebo-controlled trials suggest that alpha-blockers likely increase the risk of major adverse events slightly (RR 2.09, 95% CI 1.13 to 3.86), corresponding to 29 more (95% CI 3 more to 75 more) major adverse events per 1000 participants.Patients treated with alpha-blockers may experience shorter stone expulsion times (mean difference (MD) -3.40 days, 95% CI -4.17 to -2.63; low-quality evidence), may use less diclofenac (MD -82.41, 95% CI -122.51 to -42.31; low-quality evidence), and likely require fewer hospitalisations (RR 0.51, 95% CI 0.34 to 0.77; moderate-quality evidence), corresponding to 69 fewer hospitalisations (95% CI 93 fewer to 32 fewer) per 1000 participants. Meanwhile, the need for surgical intervention appears similar (RR 0.74, 95% CI 0.53 to 1.02; low-quality evidence), corresponding to 28 fewer surgical interventions (95% CI 51 fewer to 2 more) per 1000 participants.A predefined subgroup analysis (test for subgroup differences; P = 0.002) suggests that effects of alpha-blockers may vary with stone size, with RR of 1.06 (95% CI 0.98 to 1.15; P = 0.16; I² = 62%) for stones 5 mm or smaller versus 1.45 (95% CI 1.22 to 1.72; P < 0.0001; I² = 59%) for stones larger than 5 mm. We found no evidence suggesting possible subgroup effects based on stone location or alpha-blocker type.

AUTHORS' CONCLUSIONS

For patients with ureteral stones, alpha-blockers likely increase stone clearance but probably also slightly increase the risk of major adverse events. Subgroup analyses suggest that alpha-blockers may be less effective for smaller (5 mm or smaller) than for larger stones (greater than 5 mm).

Alpha blockers in the management of ureteric lithiasis: A meta-analysis

INTRODUCTION

Effective medical expulsion for ureteric stones with α-blockers offers numerous advantages over surgical alternatives. However, its effectiveness remains uncertain and with the publication of new trial data, the available evidence requires reappraisal.

OBJECTIVE

The aim of this study was to assess the efficacy of α-blockers the management of ureteric lithiasis.

METHODS

A systematic review of the literature, with predefined search criteria, was conducted using PubMed and Embase. All randomised trials comparing α-blocker monotherapy to placebo or standard therapy were included. Stone expulsion rate was the primary outcome measure. Secondary outcome measures were time to stone expulsion, analgesic usage and pain scores. Subgroup analyses assessed individual adrenergic antagonists and variations in standard therapy. Sensitivity analysis was based on stone location, stone size, Cochrane Risk of Bias score and study protocol. Summary effects were calculated using a random-effect model and presented as Relative risks (RR) and mean differences (MD) for dichotomous and continuous outcome measures, respectively.

RESULTS

Sixty-seven studies randomising 6654 patients were included in the meta-analysis. Stone expulsion rates improved with α-blockers (RR, 1.49; 95% CI 1.38-1.61). Contrast enhanced funnel showed evidence of publication bias. Stone expulsion time was 3.99 days (CI -4.75 to -3.23) shorter with α-blockers. Similarly, patients required 106.53 mg [CI -148.20 to -64.86] less diclofenac compared with control/placebo, and had 0.80 [CI -1.07 to -0.54] fewer pain episodes. Visual Analogue Scores were also reduced, -2.43 [CI -3.87 to -0.99]. All formulations of α-antagonists all demonstrated beneficial effects over conservative treatment/placebo. Sensitivity analysis demonstrated significant effects of stone location, stone size and study design.

CONCLUSIONS AND RELEVANCE

Despite the opposing results of recently published trial, current evidence continues to demonstrate a potential benefit of α-blocker treatment particularly for distal stones over 5 mm.

Alpha blockers for treatment of ureteric stones: systematic review and meta-analysis

OBJECTIVE

 To investigate the efficacy and safety of alpha blockers in the treatment of patients with ureteric stones.

DESIGN

 Systematic review and meta-analysis.

DATA SOURCES

 Cochrane Central Register of Controlled Trials, Web of Science, Embase, LILACS, and Medline databases and scientific meeting abstracts to July 2016.

REVIEW METHODS

 Randomized controlled trials of alpha blockers compared with placebo or control for treatment of ureteric stones were eligible. : Two team members independently extracted data from each included study. The primary outcome was the proportion of patients who passed their stone. Secondary outcomes were the time to passage; the number of pain episodes; and the proportions of patients who underwent surgery, required admission to hospital, and experienced an adverse event. Pooled risk ratios and 95% confidence intervals were calculated for the primary outcome with profile likelihood random effects models. Cochrane Collaboration's tool for assessing risk of bias and the GRADE approach were used to evaluate the quality of evidence and summarize conclusions.

RESULTS

 55 randomized controlled trials were included. There was moderate quality evidence that alpha blockers facilitate passage of ureteric stones (risk ratio 1.49, 95% confidence interval 1.39 to 1.61). Based on a priori subgroup analysis, there seemed to be no benefit to treatment with alpha blocker among patients with smaller ureteric stones (1.19, 1.00 to 1.48). Patients with larger stones treated with an alpha blocker, however, had a 57% higher risk of stone passage compared with controls (1.57, 1.17 to 2.27). The effect of alpha blockers was independent of stone location (1.48 (1.05 to 2.10) for upper or middle stones; 1.49 (1.38 to 1.63) for lower stones). Compared with controls, patients who received alpha blockers had significantly shorter times to stone passage (mean difference -3.79 days, -4.45 to -3.14; moderate quality evidence), fewer episodes of pain (-0.74 episodes, -1.28 to -0.21; low quality evidence), lower risks of surgical intervention (risk ratio 0.44, 0.37 to 0.52; moderate quality evidence), and lower risks of admission to hospital (0.37, 0.22 to 0.64; moderate quality evidence). The risk of a serious adverse event was similar between treatment and control groups (1.49, 0.24 to 9.35; low quality evidence).

CONCLUSIONS

 Alpha blockers seem efficacious in the treatment of patients with ureteric stones who are amenable to conservative management. The greatest benefit might be among those with larger stones. These results support current guideline recommendations advocating a role for alpha blockers in patients with ureteric stones.

SYSTEMATIC REVIEW REGISTRATION

 PROSPERO registration No CRD42015024169.

Oral dissolution therapy for radiolucent kidney stones. An old treatment revisited

Objective:

We present our experience using oral bicarbonate as a dissolution therapy for radiolucent kidney stones in the pre-dual energy CT era.

Methods:

A retrospective analysis of dissolution therapy was undertaken over a four-year period. Stones were diagnosed as radiolucent on conventional KUB X-ray in combination with either ultrasound or CT KUB. Oral bicarbonate was given at a dose of 2 g tds orally, increased to 2 g five times daily according to urinary pH. Patients monitored their own urine dipstick daily to achieve a pH of at least seven.

Results:

Altogether 27 patients were identified with radiolucent stones. Stone size varied from 4–40 mm. Average length of therapy was nine weeks. Of the patients, 17 had renal U/S and six had CT KUB as end point imaging. We found that 39% had complete dissolution, 18% had a partial response and 43% showed no response. A high serum uric acid level correlated with a higher incidence of dissolution. Cost-benefit analysis shows bicarbonate therapy to be more cost-effective than lithotripsy, ureteroscopy or nephrolithotomy.

Conclusions:

Bicarbonate therapy remains an attractive option for the treatment of radiolucent kidney stones. The presence of hyperuricaemia or hyperuricosuria appears to influence the success rate. Further prospective randomised studies are needed to identify the most tolerable and effective treatment regime as well as the optimal duration of treatment. Dual-energy CT may hold the key to identifying patients most likely to benefit from treatment.

CUA Guideline: Management of ureteral calculi

The focus of this guideline is the management of ureteral stones. Specifically, the topics covered include: conservative management, medical expulsive therapy, active intervention with either shockwave lithotripsy (SWL) or ureteroscopy (URS), factors affecting SWL treatment success, optimizing success, and special considerations (e.g., pregnancy, urinary diversion). By performing extensive literature reviews for each topic evaluated, we have generated an evidence-based consensus on the management of ureteral stones. The objective of this guideline is to help standardize the treatment of ureteral stones to optimize treatment outcomes.

Citrate salts for preventing and treating calcium containing kidney stones in adults

BACKGROUND

Kidney stones affect people worldwide and have a high rate of recurrence even with treatment. Recurrences are particularly prevalent in people with low urinary citrate levels. These people have a higher incidence of calcium phosphate and calcium oxalate stones. Oral citrate therapy increases the urinary citrate levels, which in turn binds with calcium and inhibits the crystallisation thus reduces stone formation. Despite the widespread use of oral citrate therapy for prevention and treatment of calcium oxalate stones, the evidence to support its clinical efficacy remains uncertain.

OBJECTIVES

The objective of this review was to determine the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Specialised Register to 29 July 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that assessed the efficacy and adverse events associated with citrate salts for the treatment and prevention of calcium containing kidney stones in adults treated for a minimum of six months.

DATA COLLECTION AND ANALYSIS

Two authors assessed studies for inclusion in this review. Data were extracted according to predetermined criteria. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes.

MAIN RESULTS

We included seven studies that included a total of 477 participants, most of whom had oxalate stones. Of these, three studies (247 participants) compared potassium citrate with placebo or no intervention; three (166 participants) compared potassium-sodium citrate with no intervention; and one (64 participants) compared potassium-magnesium citrate with placebo. Overall, quality of the reporting of the included studies was considered moderate to poor, and there was a high risk of attrition bias in two studies.Compared with placebo or no intervention, citrate therapy significantly reduced the stone size (4 studies, 160 participants: RR 2.35, 95% CI 1.36 to 4.05). New stone formation was significantly lower with citrate therapy compared to control (7 studies, 324 participants: RR 0.26, 95% CI 0.10 to 0.68). The beneficial effect on stone size stability was also evident (4 studies, 160 participants: RR 1.97, 95% CI 1.19 to 3.26). Adverse events were reported in four studies, with the main side effects being upper gastrointestinal disturbance and one patient reported a rash. There were more gastrointestinal adverse events in the citrate group; however this was not significant (4 studies, 271 participants: RR 2.55, 95% CI 0.71 to 9.16). There were significantly more dropouts due to adverse events with citrate therapy compared to control (4 studies, 271 participants: RR 4.45, 95% CI 1.28 to 15.50). The need for retreatment was significantly less with citrate therapy compared to control (2 studies, 157 participants: RR 0.22, 95% CI 0.06 to 0.89).

AUTHORS' CONCLUSIONS

Citrate salts prevent new stone formation and reduce further stone growth in patients with residual stones that predominantly contain oxalate. The quality of reported literature remains moderate to poor; hence a well-designed statistically powered multi-centre RCT is needed in order to answer relevant questions concerning the efficacy of citrate salts.

EAU Guidelines on Diagnosis and Conservative Management of Urolithiasis

CONTEXT

Low-dose computed tomography (CT) has become the first choice for detection of ureteral calculi. Conservative observational management of renal stones is possible, although the availability of minimally invasive treatment often leads to active treatment. Acute renal colic due to ureteral stone obstruction is an emergency that requires immediate pain management. Medical expulsive therapy (MET) for ureteral stones can support spontaneous passage in the absence of complicating factors. These guidelines summarise current recommendations for imaging, pain management, conservative treatment, and MET for renal and ureteral stones. Oral chemolysis is an option for uric acid stones.

OBJECTIVE

To evaluate the optimal measures for diagnosis and conservative and medical treatment of urolithiasis.

EVIDENCE ACQUISITION

Several databases were searched for studies on imaging, pain management, observation, and MET for urolithiasis, with particular attention to the level of evidence.

EVIDENCE SYNTHESIS

Most patients with urolithiasis present with typical colic symptoms, but stones in the renal calices remain asymptomatic. Routine evaluation includes ultrasound imaging as the first-line modality. In acute disease, low-dose CT is the method of choice. Ureteral stones <6mm can pass spontaneously in well-controlled patients. Sufficient pain management is mandatory in acute renal colic. MET, usually with α-receptor antagonists, facilitates stone passage and reduces the need for analgesia. Contrast imaging is advised for accurate determination of the renal anatomy. Asymptomatic calyceal stones may be observed via active surveillance.

CONCLUSIONS

Diagnosis, observational management, and medical treatment of urinary calculi are routine measures. Diagnosis is rapid using low-dose CT. However, radiation exposure is a limitation. Active treatment might not be necessary, especially for stones in the lower pole. MET is recommended to support spontaneous stone expulsion.

PATIENT SUMMARY

For stones in the lower pole of the kidney, treatment may be postponed if there are no complaints. Pharmacological treatment may promote spontaneous stone passage.

Fluorescence imaging for a noninvasive in vivo toxicity-test using a transgenic silkworm expressing green fluorescent protein

In drug development, the toxicity of candidate chemicals must be carefully examined in an animal model. Here we developed a live imaging technique using silkworms for a noninvasive toxicity test applicable for drug screening. Injection of carbon tetrachloride, a tissue-injuring chemical, into transgenic silkworms expressing green fluorescent protein (GFP) induced leakage of GFP from the tissues into the hemolymph. The leakage of GFP was suppressed by pre-administration of either cimetidine, a cytochrome P450 inhibitor, or N-acetyl cysteine, a free-radical scavenger. The transgenic silkworm was made transparent by feeding a diet containing chemicals that inhibit uric acid deposition in the epithelial cells. In the transparent silkworms, GFP fluorescence in the fat body could be observed from outside the body. Injection of salicylic acid or iron sulfate, tissue-injuring chemicals, into the transparent silkworms decreased the fluorescence intensity of the GFP in the fat body. These findings suggest that the transparent GFP-expressing silkworm model is useful for evaluating the toxicity of chemicals that induce tissue injury.

Update on the evaluation of repeated stone formers

Office management of stone disease is an important component of a urologist's practice. Evaluation should include analysis of stone composition, 24-hour urine studies, identification of modifiable risk factors, and targeted dietary, lifestyle, and/or medical therapy. A sizeable portion of investigated etiologies and risk factors for stone disease have centered on the complex interplay between obesity, diabetes, and other disease states that comprise the metabolic syndrome. Alternatives to traditional preventive therapy, such as probiotics and various fruit juices, are still being studied but may prove useful adjuncts to traditional preventive therapy, where the mainstays remain increased fluid intake, dietary modification, and pharmacologic therapy. Future studies on preventive therapy of urolithiasis are likely to focus on strategies to increase compliance, cost-effectiveness, and systems-based implementation.