Who Forms Stones and Why?

Epidemiologic aspects of urinary tract stone disease are presented as a background for understanding of the clinical impact of this pathologic condition. The principles for and the determinants of the formation of calcium stones, uric acid stones, infection stones, and cystine stones are briefly discussed in a way that should provide a necessary basis for the design of rational recurrence preventive measures. Emphasis is placed on the mechanisms behind calcium oxalate stone formation. The article highlights some recent observations and conclusions of importance for a better understanding of how stones form and of how recurrence prevention can best be achieved.