Treatment Options for Renal Stones
The treatment of renal stones should follow a stepwise approach based on stone size, location, and patient factors, with increased fluid intake to achieve at least 2.5 liters of urine output daily as the cornerstone of both prevention and treatment for all stone formers. 1
Initial Evaluation and Diagnosis
- Stone analysis: When available, clinicians should obtain stone analysis at least once to determine composition (calcium oxalate, calcium phosphate, uric acid, cystine, or struvite) 1
- Imaging studies: Review available imaging to quantify stone burden and identify anatomical abnormalities 1
- Metabolic testing: Perform 24-hour urine collections for high-risk or recurrent stone formers, analyzing for:
Treatment Algorithm Based on Stone Type and Size
1. Small Asymptomatic Stones (<4mm)
- Active surveillance with increased fluid intake is appropriate 3
- Monitor with periodic imaging to assess for stone growth
2. Symptomatic Stones (Pain Management)
- First-line pain control: NSAIDs (preferred over opioids due to fewer side effects and less need for rescue analgesia) 4
- Medical expulsive therapy (MET): For uncomplicated distal ureteral stones ≤10mm 5
3. Stones Requiring Intervention
Based on size, location, and composition:
- Extracorporeal shock wave lithotripsy (ESWL): Typically for stones <2cm
- Ureteroscopy: Effective for ureteral stones and some renal stones
- Percutaneous nephrolithotomy: For larger stones (>2cm) or complex cases
- Ureteral stents or nephrostomy tubes: For obstruction or infection 5
Medical Management Based on Stone Type
Calcium Stones (75-80% of all stones)
- Fluid intake: Achieve urine output of at least 2.5 liters daily 1
- Dietary calcium: Maintain normal intake (1,000-1,200 mg daily), avoid low calcium diets 1, 2
- Sodium restriction: Limit to <2,300 mg daily 1, 2
- For hypercalciuria: Thiazide diuretics (hydrochlorothiazide 25mg twice daily, chlorthalidone 25mg daily, or indapamide 2.5mg daily) 1, 2
- For hypocitraturia: Potassium citrate (30-80 mEq/day in divided doses) 1, 2
- For hyperuricosuria with normal calcium: Allopurinol 1
Uric Acid Stones (10-15% of stones)
- Increase urine pH: Potassium citrate to maintain urine pH 6.0-6.5 2
- Allopurinol: For hyperuricosuria or hyperuricemia
Cystine Stones (1-2% of stones)
- High fluid intake: Target urine output >4 liters daily to maintain cystine concentration <250 mg/L 1
- Sodium restriction: <2,300 mg daily 1
- Urinary alkalinization: Potassium citrate to maintain urine pH >7.0
- Thiol-binding agents: For refractory cases
Struvite Stones (Infection stones)
- Complete surgical removal of stone material
- Antibiotic therapy based on urine culture
- Urinary acidification to prevent recurrence
Prevention of Recurrence
- Follow-up monitoring: Repeat 24-hour urine collection within 6 months of treatment initiation and annually thereafter 2
- Dietary modifications:
Special Considerations
- Metabolic syndrome components (obesity, diabetes, hypertension) increase stone risk and should be addressed 1, 6
- Combination therapy with thiazides and potassium citrate may be necessary for persistent stone formation despite addressing metabolic abnormalities 2
- Underlying conditions (inflammatory bowel disease, primary hyperparathyroidism) must be treated to reduce recurrence risk 2
Common Pitfalls to Avoid
- Inadequate fluid intake: Most common preventable factor in stone formation
- Excessive calcium restriction: May paradoxically increase stone risk
- Sodium excess: Increases urinary calcium excretion
- Inadequate follow-up: Failure to monitor metabolic parameters and adherence to therapy
- Overlooking underlying conditions: Missing treatable metabolic disorders that contribute to stone formation