How to prevent kidney stones?

Prevention of Kidney Stones

The most effective strategy to prevent kidney stones is to increase fluid intake to achieve a urine output of at least 2-2.5 liters per day, combined with dietary modifications tailored to stone type and pharmacological therapy when indicated. 1

Fluid Intake

• Increase fluid intake to achieve urine volume of at least 2.5 liters daily 1
• Aim for oral intake of at least 3 liters of fluid per day 2
• Spread fluid intake throughout the day to maintain consistent urine dilution 1
• Certain beverages may provide additional benefits beyond hydration:
  • Coffee (caffeinated and decaffeinated), tea, wine, and orange juice have been associated with lower risk of stone formation 1
  • Avoid sugar-sweetened beverages which may increase stone risk 1
  • Consider water with lower calcium content to reduce risk of calcium oxalate stones 3

Dietary Modifications

For Calcium Stones (80% of all kidney stones):

• Calcium intake: Consume 1,000-1,200 mg per day of dietary calcium 1
  • Contrary to common belief, normal dietary calcium intake reduces stone risk 1, 4
  • Avoid calcium supplements, which may increase stone risk unlike dietary calcium 1
• Sodium restriction: Limit sodium intake to 2,300 mg (100 mEq) daily 1
  • Higher sodium intake increases urinary calcium excretion and stone risk 4
• Oxalate management: Limit oxalate-rich foods, especially important for those with hyperoxaluria 1
• Animal protein: Limit to 0.8-1.0 g/kg body weight/day 2
• Increase fruits and vegetables: These foods provide citrate and help maintain alkaline urine 2

For Uric Acid Stones:

• Limit animal protein intake 2
• Increase plant protein consumption 2
• Alkalinize urine through diet high in fruits and vegetables 5

For Cystine Stones:

• Significantly higher fluid intake (4+ liters daily) to achieve urinary cystine concentration below 250 mg/L 1
• Limit sodium intake to 2,300 mg or less daily 1
• Restrict animal protein intake to reduce cystine substrate load 1

Pharmacological Management

When dietary modifications and increased fluid intake fail to prevent stone recurrence, medication therapy should be initiated:

1. For calcium stones with hypercalciuria:

   • Thiazide diuretics (hydrochlorothiazide 25 mg twice daily, chlorthalidone 25 mg daily, or indapamide 2.5 mg daily) 1
   • Continue dietary sodium restriction to maximize thiazide effectiveness 1
   • Potassium supplementation may be needed with thiazide therapy 1

2. For calcium stones with hypocitraturia:

   • Potassium citrate therapy 1
   • Prefer potassium citrate over sodium citrate to avoid increasing urinary calcium 1

3. For calcium oxalate stones with hyperuricosuria:

   • Allopurinol (200-300 mg/day) 6
   • Dosage may be adjusted based on 24-hour urinary urate measurements 6

Monitoring and Follow-up

• Perform metabolic testing with 24-hour urine collections to identify specific risk factors 1
• Analyze urine for volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 1
• Use follow-up 24-hour urine collections to monitor response to interventions 1

Special Considerations

• Obesity increases kidney stone risk; maintain healthy body weight 2, 5
• Environmental factors: Ensure adequate fluid compensation when working in high-temperature environments 2
• Avoid supplements: Excessive vitamin C and vitamin D supplements may increase stone risk 2
• Medical conditions: Address underlying conditions that contribute to stone formation (e.g., inflammatory bowel disease, primary hyperparathyroidism) 1

By implementing these preventive strategies, the risk of kidney stone recurrence can be significantly reduced, improving quality of life and preventing complications associated with kidney stone disease.