Medical prevention and treatment of urinary stones

Despite revolutionary developments in minimally invasive methods for the re moval of stones in the last 15 years, the medical prevention of urinary sto nes remains very rewarding, due to the continual increase in the prevalence of nephrolithiasis in western countries, the high recurrence rate of the d isease, its complications, discomfort and the costs of lithotripsy. Medical prevention is highly effective (50-95% efficacy in different series) and c ost-convenient; its basic elements are appropriate metabolic evaluation, ad equate hydration, "common sense" diet, and, in selected cases, drugs of pro ven efficacy. Clinical-metabolic evaluation should aim at the recognition o f specific types of nephrolithiasis, and sort out secondary and/or remediab le cases, define urinary risk factors, assess patients' compliance and the side effects of any therapy during follow-up. Hydration has proved effectiv e in clinical trials and population-based observational studies; "fluids" m ay consist of water (any kind), coffee (caffeinated or decaffeinated), tea, beer and wine; grapefruit juice appears to have an unexplained ill effect. Despite the lack of clinical demonstration that dietary manipulations redu ce the recurrences of stones, biochemical and epidemiological data suggest that high sodium, animal protein and sucrose intake increase the risk. Undu e reductions in Ca intake also appear to be detrimental both for stone recu rrences and bone mineralisation: "adequate" Ca intake (800-1000 mg/day) sho uld be encouraged, but only in food since supplemental Ca, as drugs, appear s to increase the risk of stones. Effective drugs are available for cystine , uric acid, infected stones and several secondary causes of Ca nephrolithi asis; in "idiopathic" Ca nephrolithiasis, thiazides, allopurinol, K and K-M g citrate and possibly neutral K phosphate have been shown to be effective, at least in specific metabolic contexts.