What are the treatment options for nephrolithiasis (kidney stones)?

Treatment of Nephrolithiasis

Treatment of kidney stones requires a stone type-specific approach combining acute pain management, stone removal when indicated, and long-term medical prevention strategies tailored to stone composition and metabolic abnormalities.

Acute Management

Pain Control

• NSAIDs (diclofenac, ibuprofen, or metamizole) are first-line therapy for renal colic, as they reduce the need for additional analgesia compared to opioids 1
• Use the lowest effective NSAID dose due to cardiovascular and gastrointestinal risks, and exercise caution in patients with reduced glomerular filtration rate 1
• Opioids (hydromorphine, pentazocine, or tramadol—but not pethidine) serve as second-line agents when NSAIDs are contraindicated or insufficient 1

Emergency Interventions

• Urgent decompression via percutaneous nephrostomy or ureteral stenting is mandatory for sepsis and/or anuria in an obstructed kidney 1
• Collect urine for antibiogram testing before and after decompression 1
• Administer antibiotics immediately and adjust based on culture results 1
• Delay definitive stone treatment until sepsis resolves 1

Medical Expulsive Therapy

• Alpha-blockers are strongly recommended for ureteral stones >5 mm in the distal ureter in patients suitable for conservative management 1

Stone-Specific Medical Management

Calcium Oxalate/Phosphate Stones (80% of cases)

First-line therapy:

• Increase fluid intake to achieve at least 2 liters of urine output daily 1, 2, 3
• Maintain normal dietary calcium intake of 1,000-1,200 mg/day rather than restricting it 2, 3
• Limit sodium intake to ≤2,300 mg daily to reduce urinary calcium excretion 2, 3
• Reduce non-dairy animal protein to 5-7 servings per week 3
• Limit dietary oxalate for patients with oxalate stones 2, 3
• Avoid sugar-sweetened beverages, particularly those acidified with phosphoric acid 2, 3

Second-line pharmacologic therapy (when dietary measures fail):

• Thiazide diuretics (hydrochlorothiazide 25 mg twice daily or 50 mg once daily, chlorthalidone 25 mg daily, or indapamida 2.5 mg daily) for hypercalciuria 2, 4
• Potassium citrate for hypocitraturia or low urinary pH 1, 2, 3
• Allopurinol (200-300 mg/day) for hyperuricosuria with recurrent calcium oxalate stones 2, 4, 3

Uric Acid Stones

Primary treatment is urinary alkalinization, NOT allopurinol:

• Potassium citrate is first-line therapy to raise urine pH to 6.0 1
• Most patients have low urinary pH rather than hyperuricosuria as the predominant risk factor 1
• Allopurinol should not be routinely offered as first-line therapy, as it will not prevent stones in patients with unduly acidic urine 1
• Oral chemolysis with alkalinization (citrate or sodium bicarbonate to pH 7.0-7.2) can dissolve existing uric acid stones 1

Cystine Stones

Stepwise approach:

• First-line: Increased fluid intake (targeting urine output >3 L/day), sodium and protein restriction, and urinary alkalinization with potassium citrate to achieve urine pH of 7.0 1
• Second-line: Cystine-binding thiol drugs (tiopronin preferred over d-penicillamine) for patients unresponsive to dietary modifications or with large recurrent stone burdens 1
• Tiopronin is more effective and has fewer adverse events than d-penicillamine 1

Struvite (Infection) Stones

• Aggressive medical approach required due to high recurrence risk 1
• Urease inhibitor (acetohydroxamic acid) may be beneficial but has extensive side effect profile 1
• Monitor for reinfection 1

Monitoring and Follow-up

Metabolic Evaluation

• Obtain 24-hour urine collection within 6 months of treatment initiation to assess response to dietary/medical therapy 1, 4
• Measure: volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 2, 4
• Continue annual 24-hour urine collections to assess adherence and metabolic response 1, 4

Safety Monitoring

• Obtain periodic blood testing to assess for adverse effects in patients on pharmacologic therapy 1
• Monitor for: hypokalemia and glucose intolerance (thiazides), elevated liver enzymes (allopurinol, tiopronin), anemia (acetohydroxamic acid, tiopronin), and hyperkalemia (potassium citrate) 1

Stone Analysis

• Perform stone analysis for all first-time stone formers 1
• Obtain repeat stone analysis in patients not responding to treatment, as stone composition may change 1

Common Pitfalls to Avoid

• Never restrict dietary calcium—this paradoxically increases urinary oxalate and stone risk 2, 3
• Avoid calcium supplements unless specifically indicated; dietary calcium sources are preferred 3
• Do not use sodium citrate or sodium bicarbonate instead of potassium citrate, as sodium load increases urinary calcium excretion 3
• Avoid excessive vitamin C supplementation (>1,000 mg/day), which increases oxalate excretion 3
• Do not offer allopurinol as first-line therapy for uric acid stones—alkalinization is primary 1
• Ensure adequate nighttime hydration to avoid urinary supersaturation during sleep 5