Kidney Stone Prevention and Treatment

Introduction to Kidney Stone Prevention

The American Urological Association recommends lifestyle modifications, including fluid intake to achieve ≥2 liters of urine output daily, as essential for all stone formers, reducing urinary supersaturation of stone-forming salts 3
Dietary sodium restriction to ≤2,300 mg/day is critical for maximizing the effectiveness of any subsequent pharmacologic therapy, as it reduces urinary calcium excretion 1, 3
Normal dietary calcium intake of 1,000-1,200 mg/day from food sources independently reduces stone risk by binding intestinal oxalate 3

The American Urological Association guidelines explicitly state that when metabolic abnormalities are present or stone formation persists despite lifestyle changes, pharmacologic therapy with potassium citrate should be offered 1, 2
Potassium citrate is indicated as Grade B evidence for recurrent calcium stones with hypocitraturia, where prospective RCTs demonstrate reduced stone recurrence 2, 4
Potassium citrate is beneficial for calcium stones with normal citrate but low urinary pH, as it raises pH and provides crystallization inhibition 4
Potassium citrate is a potent inhibitor of calcium phosphate crystallization and is indicated for calcium phosphate stone formers with hypocitraturia 2, 4
Potassium citrate is first-line therapy for uric acid stones, targeting urinary pH of 6.0-6.5, as most uric acid stone formers have unduly acidic urine rather than hyperuricosuria 3, 4
Potassium citrate is indicated for cystine stones, targeting urinary pH of 7.0 to enhance cystine solubility 1, 4

All stone formers should implement lifestyle modifications, including fluid intake ≥2L urine output, sodium ≤2,300 mg/day, and dietary calcium 1,000-1,200 mg/day 3
A 24-hour urine collection should be obtained to measure volume, pH, calcium, oxalate, citrate, uric acid, and sodium 3
If hypocitraturia is present or stone formation persists despite lifestyle changes, potassium citrate therapy should be added 1, 2, 4
For uric acid stones, potassium citrate is first-line pharmacologic therapy regardless of lifestyle adherence, as urinary alkalinization is essential 3, 4
Reassess with 24-hour urine within 6 months of initiating treatment, then annually or more frequently based on stone activity 1, 3

Potassium citrate is preferred over sodium citrate because sodium loading may increase urinary calcium excretion and promote mixed stone formation 3, 4
Avoid raising urinary pH above 7.0 in calcium stone formers, as this increases the risk of calcium phosphate stone formation 3
Dietary modifications must continue when potassium citrate is prescribed, especially sodium restriction, to maximize hypocalciuric effects and prevent potassium wasting 2
Lifestyle control alone is appropriate only for patients who remain stone-free without metabolic abnormalities on 24-hour urine testing 1