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SUMMARYRecurrent stone formation in the urinary tract is a common and important problem that must be considered in daily urological practice. With a prevalence of> 10% and an expected recurrence rate of ≈ 50%, stone disease has an important effect on the healthcare system. It is generally agreed that patients with uric acid/urate, cystine or infection stones always should be treated pharmacologically. For calcium stone formers the treatment should be chosen according to the severity of the disease. Recurrence in patients with calcium‐stone disease can be prevented with general or specific dietary and drinking advice, and with pharmacological therapy. For idiopathic calcium stone formers the most convincing therapeutic effects have been reported with thiazide and alkaline citrate.

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The Consensus Group deliberated on a number of questions concerning urine and stone analysis over a period of months, and then met to develop consensus. The Group concluded that analyses of urine and stones should be routine in the diagnosis and treatment of urinary stone diseases. At present, the 24-h urine is the most useful type of urine collection, and accepted methods for analysis are described. Patient education is also important for obtaining a proper urine sample. Graphical methods for reporting urine analysis results can be helpful both for the physician and for educating the patient as to proper dietary changes that could be beneficial. Proper analysis of stones is also essential for diagnosis and management of patients. The Consensus Group also agreed that research has shown that evaluation of urinary crystals could be very valuable, but the Group also recognizes that existing methods for assessment of crystalluria do not allow this to be part of stone treatment in many places.

Each of 92 patients in a Swedish district served by only one hospital had been treated for their first renal stone in 1977 and was evaluated 10 years later. Recurrent stone formation during the observation period was observed in 26% of the patients, with no difference between men and women. Of all the patients who had sought medical advice in 1977 because of urinary stone colic, 51% were experiencing their first stone episode. Ten years later 37% of the original patients were still classified as single stone formers. The recorded recurrence rate was lower than that previously reported in the literature.

Approximate estimates of the ion-acitivity products of calcium phosphate and calcium oxalate in distal tubular urine were derived from the 16-h urinary excretion of calcium, oxalate, citrate, magnesium and phosphate. Urine variables were obtained from 96 normal subjects and 277 calcium stone formers and the calculations were carried out with iterative approximation using the EQUIL2 program. With respect to other ions of importance for the ion-activity products, the urine was assumed to have a fixed composition with pH 6.45. Significantly higher ion-activity products of both calcium phosphate and calcium oxalate were recorded in stone formers. It was concluded that diurnal variations in urine composition and pH might result in peaks of calcium phosphate supersaturation in distal tubular urine whereby a crystallization can occur. In association with abnormalities in terms of promotion and inhibition of calcium salt crystallization, such a precipitation can be of importance for the subsequent formation of calcium renal stones.

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