M. Gelosa

Dietary treatment of urinary risk factors for renal stone formation. A review of CLU Working Group

OBJECTIVE Diet interventions may reduce the risk of urinary stone formation and its recurrence, but there is no conclusive consensus in the literature regarding the effectiveness of dietary interventions and recommendations about specific diets for patients with urinary calculi. The aim of this study was to review the studies reporting the effects of different dietary interventions for the modification of urinary risk factors in patients with urinary stone disease. MATERIALS AND METHODS A systematic search of the Pubmed database literature up to July 1, 2014 for studies on dietary treatment of urinary risk factors for urinary stone formation was conducted according to a methodology developed a priori. Studies were screened by titles and abstracts for eligibility. Data were extracted using a standardized form and the quality of evidence was assessed. RESULTS Evidence from the selected studies were used to form evidence-based guideline statements. In the absence of sufficient evidence, additional statements were developed as expert opinions. CONCLUSIONS General measures: Each patient with nephrolithiasis should undertake appropriate evaluation according to the knowledge of the calculus composition. Regardless of the underlying cause of the stone disease, a mainstay of conservative management is the forced increase in fluid intake to achieve a daily urine output of 2 liters. HYPERCALCIURIA: Dietary calcium restriction is not recommended for stone formers with nephrolithiasis. Diets with a calcium content ≥ 1 g/day (and low protein-low sodium) could be protective against the risk of stone formation in hypercalciuric stone forming adults. Moderate dietary salt restriction is useful in limiting urinary calcium excretion and thus may be helpful for primary and secondary prevention of nephrolithiasis. A low-normal protein intake decrease calciuria and could be useful in stone prevention and preservation of bone mass. Omega-3 fatty acids and bran of different origin decreases calciuria, but their impact on the urinary stone risk profile is uncertain. Sports beverage do not affect the urinary stone risk profile. HYPEROXALURIA: A diet low in oxalate and/or a calcium intake normal to high (800-1200 mg/day for adults) reduce the urinary excretion of oxalate, conversely a diet rich in oxalates and/or a diet low in calcium increase urinary oxalate. A restriction in protein intake may reduce the urinary excretion of oxalate although a vegetarian diet may lead to an increase in urinary oxalate. Adding bran to a diet low in oxalate cancels its effect of reducing urinary oxalate. Conversely, the addition of supplements of fruit and vegetables to a mixed diet does not involve an increased excretion of oxalate in the urine. The intake of pyridoxine reduces the excretion of oxalate. HYPERURICOSURIA: In patients with renal calcium stones the decrease of the urinary excretion of uric acid after restriction of dietary protein and purine is suggested although not clearly demonstrated. HYPOCITRATURIA: The administration of alkaline-citrates salts is recommended for the medical treatment of renal stone-formers with hypocitraturia, although compliance to this treatment is limited by gastrointestinal side effects and costs. Increased intake of fruit and vegetables (excluding those with high oxalate content) increases citrate excretion and involves a significant protection against the risk of stone formation. Citrus (lemons, oranges, grapefruit, and lime) and non citrus fruits (melon) are natural sources of dietary citrate, and several studies have shown the potential of these fruits and/or their juices in raising urine citrate levels. CHILDREN There are enought basis to advice an adequate fluid intake also in children. Moderate dietary salt restriction and implementation of potassium intake are useful in limiting urinary calcium excretion whereas dietary calcium restriction is not recommended for children with nephrolithiasis. It seems reasonable to advice a balanced consumption of fruit and vegetables and a low consumption of chocolate and cola according to general nutritional guidelines, although no studies have assessed in pediatric stone formers the effect of fruit and vegetables supplementation on urinary citrate and the effects of chocolate and cola restriction on urinary oxalate in pediatric stone formers. Despite the low level of scientific evidence, a low-protein (< 20 g/day) low-salt (< 2 g/day) diet with high hydration (> 3 liters/day) is strongly advised in children with cystinuria. ELDERLY: In older patients dietary counseling for renal stone prevention has to consider some particular aspects of aging. A restriction of sodium intake in association with a higher intake of potassium, magnesium and citrate is advisable in order to reduce urinary risk factors for stone formation but also to prevent the loss of bone mass and the incidence of hypertension, although more hemodynamic sensitivity to sodium intake and decreased renal function of the elderly have to be considered. A diet rich in calcium (1200 mg/day) is useful to maintain skeletal wellness and to prevent kidney stones although an higher supplementation could involve an increase of risk for both the formation of kidney stones and cardiovascular diseases. A lower content of animal protein in association to an higher intake of plant products decrease the acid load and the excretion of uric acid has no particular contraindications in the elderly patients, although overall nutritional status has to be preserved.

Medical Expulsive Therapy for Symptomatic Distal Ureter Stones: Is the Combination of Bromelain and Tamsulosin More Effective than Tamsulosin Alone? Preliminary Results of a Single-Center Study

Objectives: To assess the safety and efficacy of bromelain plus tamsulosin versus tamsulosin alone as medical expulsive therapy (MET) for promoting spontaneous stone passage (SSP) of symptomatic distal ureter stones. Patients and Methods: One-hundred-fourteen patients with a 4–10 mm distal ureteral stone were enrolled (Group A). Patients self-administered daily bromelain with tamsulosin for 30 days or until SSP or intervention was mandatory. Patients were compared to those from a control group taking tamsulosin as MET (Group B) and matched for the following factors: sex, age ±10%, stone diameter. A logistic regression model evaluated bromelain and the ureteral stone diameter as explanatory variables. Results: SSP rates were 87.7 vs. 75.4% for group A vs. group B respectively (p = 0.016); with no difference observed for the time to self-reported stone expulsion (11.68 vs. 11.57 days; p = 0.91). Considering larger stones (> 5 mm), the SSP rate was 83.3% in group A and 61% in group B (p < 0.01). With each millimeter increment of stone diameter, the probability of SSP decreased by 59.1% (p < 0.0001), while it increased of 3.3 when bromelain was present. Only 3 cases of tamsulosin-related adverse events were recorded. Conclusion: The association of bromelain and tamsulosin as MET increases the probability of SSP of symptomatic distal ureteral stones, with no bromelain-related side effects recorded.

Shock wave lithotripsy in the elderly: our experience related to literature review

Background The more and more common use of abdominal ultrasonography and of other imaging techniques, the increase of the life expectancy and therapies for calcium metabolism, has led to a higher diagnosis rate of renal stones in the elderly. At the moment, extracorporeal shock wave lithotripsy is considered the first-line therapy in the majority of reno-ureteral stones. Objectives To prove the efficacy and safety of extracorporeal shock wave lithotripsy also in the elderly population. Materials and Methods We proceeded to a retrospective study on patients aged over 70 years, who underwent SWL at our division from January 1996 to April 2005, with Storz Modulith SLX electromagnetic lithotripter. We defined as stone-free those patients who did not show any stone fragment in the following ultrasonography and abdomen X-ray control. In addition, we performed a medium/long-term follow-up. We adopted as “control group” 115 patients aged less than 60 years, who underwent lithotripsy with the same lithotripter from June 2007 to January 2008. Results In the short-term follow-up, at the end of the single treatment or of the course of treatments (1-3 months after treatment), we observed: 72.1% (83/115) stone-free subjects, 20% (23/115) of cases with stone fragments that could be eliminated (<4 mm), 3.5% (4/115) with stone fragments >4 mm, 4.3% (5/115) unchanged cases; 2 of these (1.7%) underwent endoscopic lithotripsy and one percutaneous lithotripsy (0.9%). Concerning the medium/long-term follow-up (mean 59.2 months, range 7 mo-108 mo), we observed: 59.8% (67/112) stone-free cases, 25.9% (29/112) recurring stones, 11.6% (13/112) re-growth, 2,7% (3/112) unchanged cases. In the short-term follow-up, comparing the study group with the control one we observed: – No statistically significant difference regarding the treatment side effects in the two groups; – A lower stone-free percentage in caliceal stones in the elderly than in the younger patients (SFR = 62.5% vs 70.3%) – A stone-free percentage for non-caliceal stones similar in the older and the young patients (SFR = 79.1% vs 80.4%). Conclusions Shock wave lithotripsy proves to be effective in the first-line treatment of renal stones in the elderly, yielding good results with no increase of side effects.

NGAL as a renal injury marker: a prospective randomized trial using Wolf PiezoLith 3000

Background Shock wave lithotripsy (SWL) has proven to be safe and effective for renal stone treatment. The shock wave rate used during the SWL procedure causes cavitation, which is the phenomenon responsible for stone fragmentation and may be responsible for tissue and vascular damages ascribed to lithotripsy. Neutrophil Gelatinase-Associated Lipocalin (NGAL) has been shown to be one of the earliest and most overexpressed markers in case of cellular damage in the kidney. Objective Using a new generation piezoelectric lithotripter, we evaluated the relation between renal damage, stone fragmentation rate, pain and shock wave rate delivered during SWL. Materials and Methods 80 patients suffering from a single renal stone were included in our clinical trial and underwent SWL with Wolf PiezoLith 300 lithotripter. A urine sample was collected in 54 patients (30 belonging to Group A, 24 to Group B) before treatment, within 2 hours and 72 hours after SWL, for NGAL measurement. Results The stone fragmentation rate obtained in the 2 groups was practically the same 30 days after SWL, with an efficacy rate of 72.7% in Group A and of 73.3% in Group B. NGAL increased after treatment, but was not statistically different in the two groups, and returned to the baseline value after 72 h. Furthermore, NGAL was always well below the threshold value of 350 ng/mL, indicative of acute renal failure. Conclusions The best stone fragmentation rate achievable with a piezoelectric lithotripter can be reached with a higher shock wave rate without significant renal damage, thus optimizing the treatment time.