What is the management and treatment for nephrolithiasis?

Management and Treatment of Nephrolithiasis

Increased fluid intake to achieve at least 2 liters of urine output daily is the cornerstone of nephrolithiasis management, followed by pharmacologic therapy with thiazide diuretics, citrate, or allopurinol when fluid therapy fails. 1

First-Line Management: Non-Pharmacological Approaches

Fluid Intake

• Increase fluid intake throughout the day to achieve at least 2 liters of urine output daily 1, 2
• No significant difference between tap water and mineral water in preventing stone recurrence 2
• Daily fluid intake should be balanced between day and night to avoid urinary supersaturation during nighttime 3
• For severe forms of nephrolithiasis (primary or enteric hyperoxaluria or cystinuria), fluid intake may need to be increased to achieve 3.5-4 liters of urine output daily 3

Dietary Modifications

• Reduce consumption of soft drinks acidified by phosphoric acid (colas) 1, 2
• Maintain normal dietary calcium intake rather than restricting it 2, 4
• Limit dietary sodium to enhance the effectiveness of other interventions 5, 4
• For patients with oxalate stones, limiting dietary oxalate may be beneficial 2, 4
• Moderate protein intake is recommended to decrease calciuria and preserve bone mass 4

Second-Line Management: Pharmacological Therapy

When increased fluid intake fails to prevent stone formation, pharmacologic therapy should be initiated based on stone type and metabolic abnormalities 1:

For Calcium Stones

• Thiazide diuretics: Effective for patients with hypercalciuria 1, 5

  • Dosages: hydrochlorothiazide (25 mg twice daily or 50 mg once daily) 5
  • Mechanism: Reduces urinary calcium excretion 5
  • Monitor for hypokalemia and other electrolyte disturbances 5

• Potassium citrate: Indicated for hypocitraturic calcium oxalate nephrolithiasis 6

  • Dosage: 30-80 mEq/day in divided doses 6
  • Mechanism: Increases urinary citrate, binds calcium, and decreases urine acidity 2
  • Contraindicated in patients with hyperkalemia 6

• Allopurinol: For patients with hyperuricosuria 1, 2

  • Mechanism: Reduces uric acid production and excretion 2
  • Generally well-tolerated with no increased risk of withdrawals compared to placebo 1

For Uric Acid Stones

• Potassium citrate: Indicated for uric acid lithiasis with or without calcium stones 6

  • Increases urinary pH from 5.3 to normal range (6.2-6.5) 6
  • Significantly reduces stone formation in patients with uric acid lithiasis 6

• Allopurinol: For patients with hyperuricosuria or hyperuricemia 2, 4

Treatment Algorithm Based on Stone Type

Calcium Stones (80% of all kidney stones) 1

1. First-line: Increase fluid intake to achieve 2L urine output daily 1
2. Second-line (if fluid therapy fails):
   • For hypercalciuria: Thiazide diuretics 1, 5
   • For hypocitraturia: Potassium citrate 6
   • For hyperuricosuria: Allopurinol 1, 2

Uric Acid Stones

1. First-line: Increase fluid intake to achieve 2L urine output daily 1, 4
2. Second-line:
   • Potassium citrate to alkalinize urine 6
   • Allopurinol for hyperuricosuria 2, 4

Monitoring and Follow-up

• Monitor serum electrolytes, creatinine, and complete blood counts every four months 6
• Perform more frequent monitoring in patients with cardiac disease, renal disease, or acidosis 6
• Obtain a 24-hour urine specimen within six months of initiating treatment to assess response to therapy 5
• Discontinue treatment if hyperkalemia, significant rise in serum creatinine, or significant fall in blood hematocrit/hemoglobin occurs 6

Important Caveats

• Monotherapy is generally as effective as combination therapy for preventing stone recurrence 1, 7
• Higher doses of thiazides are associated with more adverse effects but have better-established effectiveness in preventing stone recurrence than lower doses 7
• Although biochemical testing is commonly used to guide treatment selection, randomized controlled trial evidence supporting this approach is limited 1, 7
• For patients with signs of infection (pyuria, bacteriuria, positive nitrites), obtain urine culture before initiating treatment 7
• In cases of sepsis and/or anuria in an obstructed kidney, urgent decompression of the system via percutaneous nephrostomy or ureteral stenting is strongly recommended 7