Initial Management and Treatment of Nephrolithiasis (Kidney Stones)
The cornerstone of initial management for nephrolithiasis is increased fluid intake to achieve at least 2 liters of urine output per day, followed by pharmacologic therapy when fluid intake alone fails to prevent stone recurrence. 1, 2
Non-Pharmacological Management
Fluid Intake
- Increased fluid intake spread throughout the day to achieve at least 2-2.5 liters of urine output daily is the first-line treatment for preventing nephrolithiasis 1, 2, 3
- Fluid intake should be balanced between day and night to avoid urinary supersaturation during nighttime 3
- Water is the preferred fluid of choice, with consideration given to its mineral composition 3
- Certain beverages like coffee, tea, wine, and orange juice may be associated with lower risk of stone formation 2
- Reducing consumption of soft drinks acidified by phosphoric acid can help reduce stone recurrence 1, 4
Dietary Modifications
- Maintain normal dietary calcium intake of 1,000-1,200 mg per day rather than restricting it 1, 2, 4
- Limit sodium intake to 2,300 mg daily to reduce urinary calcium excretion 2
- Consume calcium from foods and beverages primarily at meals to enhance gastrointestinal binding of oxalate 2
- Avoid calcium supplements unless specifically indicated, as they may increase stone risk compared to dietary calcium 2
- Limit dietary oxalate for patients with oxalate stones 1, 4
- Reduce non-dairy animal protein intake to 5-7 servings of meat, fish, or poultry per week 2
- Avoid sugar-sweetened beverages as they may increase stone risk 2
Pharmacological Management
When to Initiate Pharmacologic Therapy
- When increased fluid intake fails to prevent stone formation, pharmacologic therapy should be initiated 5, 1, 2
Medication Selection Based on Stone Type
- For calcium stones:
- Thiazide diuretics are effective in reducing calcium stone recurrence, particularly beneficial for patients with hypercalciuria 1, 2, 4
- Potassium citrate therapy effectively reduces recurrence of calcium stones by binding to calcium and decreasing urine acidity 1, 2, 4
- Allopurinol is recommended for patients with recurrent calcium oxalate stones who have hyperuricosuria and normal urinary calcium 2, 4
- For uric acid stones:
Evaluation and Monitoring
Initial Assessment
- Obtain urinalysis including dipstick and microscopic evaluation to assess urine pH, indicators of infection, and identify crystals that may indicate stone type 4
- Consider urine culture if urinalysis suggests urinary tract infection or if the patient has a history of recurrent UTIs 4
- Consider stone analysis at least once to guide treatment decisions 4
Metabolic Evaluation
- Obtain 24-hour urine collections to assess metabolic abnormalities and guide therapy 2
- Parameters to measure include volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 2
Special Considerations
Infection-Associated Stones
- In cases of sepsis and/or anuria in an obstructed kidney, urgent decompression of the system via either percutaneous nephrostomy or ureteral stenting is strongly recommended 4, 6
- Definitive treatment of the stone should be delayed until sepsis is resolved 4
- Complete eradication of infection stones with percutaneous nephrolithotomy or extracorporeal shock wave lithotripsy is required 6
Pain Management
- Consider non-opioid treatment as initial management of pain associated with nephrolithiasis in light of the current opioid epidemic 7
Common Pitfalls to Avoid
- Restricting dietary calcium, which can paradoxically increase stone risk by increasing urinary oxalate 2
- Using sodium citrate instead of potassium citrate, as the sodium load can increase urinary calcium 2
- Overreliance on calcium supplements rather than dietary calcium sources 2
- Recommending oxalate restriction to individuals with pure uric acid stones or those with low urinary oxalate excretion 2