Nephrolithiasis: Treatment, causes, and prevention

Factors that promote stone formation include low daily urine volumes; saturation of the urine with calcium, oxalate, calcium phosphate, uric acid, or cystine; acidic urine; and bacterial infection. The author identifies the mechanisms of stone formation and outlines management aimed at preventing recurrences. Key points During an acute stone event, medical management focuses on pain control. Hydration and certain drugs may help the stone to pass. Most stones are composed of calcium oxalate or calcium phosphate. Less common are uric acid, magnesium ammonium phosphate, and cystine stones. To prevent stones from recurring, patients who have had any type of stone should maintain an adequate fluid intake to keep the urine dilute. Paradoxically, calcium restriction is not warranted for patients who have had calcium stones, and may even be harmful. Alkalinization of the urine may help prevent recurrent uric acid stones and cystine stones.