Background
represents a common referral for urologists To improve the efficiency of stone evaluation, referring physicians could use a questionnaire that includes common stone-predisposing medical conditions, stone preventing the promoting medications (including vitamins and calcium supplements), family history of stone (first-degree), relatives), previous stone treatments and prior results of stone disease evaluations. A dietary history, specifically focused one on fluid intake as well as consumption of animal protein to dairy products, and salt usage should be included with this questionnaire. Strong evidence that would support going beyond the minimal evaluation in Figure 1 is lacking
The 24-hour urine collection requires an assessment of the minimum components required of volume, creatinine, calcium, sodium, citrate, oxalate and uric acid. Depending on laboratory availability, additional parameters, such as potassium, phosphorus, sulphate ammonia and urea nitrogen, can be requested to allow the calculations of supersaturations for calcium oxalate, uric acid and brushite (calcium phosphate). Within the Canadian and European context, the calculation of supersaturation is neither readily available nor required to produce a reduction in stone recurrence
Screening for primary hyperparathyroidism in the absence of a high-normal or elevated serum calcium is not recommended. The presence of pure calcium phosphate stone disease should prompt a review of the serum electrolytes (to rule out complete distal renal tubular acidosis) and the serum calcium (to exclude primary hyperparathyroidism).