Medical management of kidney stones: AUA guideline.

Effective strategies for preventing recurrence are important in the care of patients with kidney stones. This review evaluated the evidence on benefits and harms of treatments to prevent recurrent ...

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Medical management to prevent recurrent nephrolithiasis in adults: a systematic review for an American College of Physicians Clinical Guideline.

The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall's plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is 200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone disease.

Idiopathic hypercalciuria and formation of calcium renal stones.

This American College of Physicians (ACP) guideline on dietary and pharmacologic management to prevent recurrent nephrolithiasis in adults recommends management with increased fluid intake spread t...

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Dietary and Pharmacologic Management to Prevent Recurrent Nephrolithiasis in Adults: A Clinical Practice Guideline From the American College of Physicians

Nephrolithiasis is a frequent condition. While it is generally accepted that such condition carries a risk of recurrence over time, the exact risk and its predictors have been rarely quantitated. We aimed to estimate recurrence of kidney stones, overall and in specific subgroups, from randomized controlled trials (RCTs) of calcium stone formers. Systematic review of RCTs of adult patients with idiopathic calcium kidney stones. Recurrence rates analyzed in subgroups based on type of intervention and other characteristics, using Poisson regression models. The analysis included 21 RCTs with 2168 participants over a median follow-up of 3.2 years (range 0.5–9.7). The median recurrence of kidney stones was 15 per 100 person–years (range 0–110). Recurrence was higher in those with two or more previous stone episodes compared to those with a single episode at enrolment (16 vs. 6 per 100 person–years, p < 0.001) and in those untreated or treated with dietary changes compared to those treated with drugs (26 vs. 23 vs. 9 per 100 person–years, p < 0.001). The effect of drugs on recurrence seemed to be beneficial only among those with two or more previous stone episodes. The overall recurrence rate of stones depends on factors such as previous stone history and type of treatment. Dietary approaches seem to be more effective among single stone formers, whereas drugs seem to be more effective among recurrent stone formers.

Risk of recurrence of idiopathic calcium kidney stones: analysis of data from the literature.

Expert’s summary: This study is a randomized comparison of patients with residual stone material in the kidney after shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PNL) who were treated with alkaline citrate (ALK) or left untreated. After a relatively short follow-up period (12 mo), there were significant differences in terms of stone-free kidneys, regrowth of residuals, and new stone formation. Of initially stone-free patients treated with ALK, 7.7% had formed new stones after 1 yr compared with 42.3% of those without such treatment. In patients with residual fragments, more patients in the ALKtreated group became stone free, and growth of residual fragments was encountered in 7.7% of the treated group and 54.5% of the control group. The conclusion from this study was that treatment with ALK gives positive effects in patients both with and without residual fragments after active stone removal. Expert’s comments: Although it has been shown previously that ALK is efficient in counteracting new calcium stone formation [1] as well as regrowth of residual fragments [2,3], this article is a valuable reminder of the usefulness of medical treatment of patients with calcium stone disease. At a time when there has been a considerable technical development of ureteroscopes and stone-disintegrating devices, the enthusiasm to use these instruments has placed recurrence prevention in the shadows, and this field is seriously neglected today. It is recognized that asymptomatic residual fragments might be present in the kidney after SWL; however, it needs to be emphasized that residual fragments are also common after retrograde intrarenal surgery and occur even after PNL. Moreover, it is also notable that in cases of obviously complete clearance of calcium stones, recurrent stone formation is considerable, with an average risk of new stone formation in as many as 5% after 1 yr and 30% after 5 yr. In the reported study, sodium potassium citrate was used as the only agent, and it is possible that this form of treatment was particularly useful for fragment clearance [4]; however, I personally am in favor of a selective recurrence prevention based on biochemical findings. The sodium content might result in increased excretion of calcium that is not entirely positive, and the follow-up period is too short for general conclusions. The message of this report, however, is clear: Considering use of medical agents to facilitate fragment passage and to counteract new stone formation and growth of residual fragments should be part of the urologic care of patients with calcium stone disease. This is particularly important for those patients who have a previous history of stone formation and for those who have asymptomatic residual fragments. Both of these groups also should have an individualized follow-up program [5].

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S Lammongkolkul

Papers

Alkaline citrate reduces stone recurrence and regrowth after shockwave lithotripsy and percutaneous nephrolithotomy