What is the best approach to pass kidney stones?

Best Way to Pass Kidney Stones

For stones ≤10mm without complications, increase fluid intake to achieve at least 2.5 liters of urine daily and use alpha-blocker medication (medical expulsive therapy) to facilitate spontaneous passage, particularly for distal ureteral stones >5mm. 1, 2

Immediate Pain Management

• NSAIDs (diclofenac, ibuprofen, or metamizole) are superior to opioids for renal colic pain control and should be used as first-line treatment, using the lowest effective dose to minimize cardiovascular and gastrointestinal risks. 2
• Reserve opioids (hydromorphine, pentazocine, or tramadol) as second-line agents only when NSAIDs are contraindicated or insufficient, and avoid pethidine due to high vomiting rates. 2
• Exercise caution with NSAIDs in patients with reduced kidney function as they may further impair renal function. 2

Conservative Management with Medical Expulsive Therapy (MET)

Alpha-blockers provide the greatest benefit for stones >5mm in the distal ureter and are considered first-line therapy for uncomplicated distal ureteral stones ≤10mm. 2, 3

Conservative management is appropriate when:

• Pain is well-controlled 2
• No signs of sepsis are present 2
• Adequate renal functional reserve exists 2
• Maximum duration should not exceed 4-6 weeks from initial presentation 2

Mandatory periodic imaging is required to monitor stone position and assess for hydronephrosis during conservative management. 2

Fluid Intake Strategy

Increase fluid intake to achieve a urine volume of at least 2.5 liters daily, which is essential to prevent stone formation and facilitate passage. 1, 4, 5

Beverage recommendations:

• Coffee, tea, wine, and orange juice are associated with lower stone formation risk 4
• Avoid sugar-sweetened beverages as they may increase stone risk 4
• Strain urine to catch passed stones for analysis 4

Dietary Modifications During Stone Passage

• Maintain normal calcium intake (1,000-1,200 mg/day) from dietary sources rather than supplements, as restricting dietary calcium may actually increase stone risk by increasing intestinal oxalate absorption. 4, 1
• Limit sodium intake to 2,300 mg daily to reduce urinary calcium excretion. 1, 4
• For calcium oxalate stones, limit intake of oxalate-rich foods while maintaining normal calcium consumption. 4
• Reduce animal protein intake, as it increases urinary calcium and uric acid excretion while reducing urinary citrate. 1

When Conservative Management Fails

If the stone fails to pass within 4-6 weeks, surgical intervention should be considered:

For distal ureteral stones:

• Ureteroscopy is first-line for stones >10mm 2
• Both ureteroscopy and shock wave lithotripsy are acceptable for stones <10mm, though ureteroscopy yields significantly higher stone-free rates 2

For proximal ureteral stones:

• Ureteroscopy is recommended as the first surgical modality regardless of stone size 1

Emergency Situations Requiring Urgent Intervention

Seek immediate medical attention if:

• Fever or signs of infection develop 4
• Severe uncontrolled pain persists 4
• Vomiting leads to dehydration 4
• Signs of urinary obstruction occur 4

In cases of sepsis and/or anuria with obstructed kidney, urgent decompression via percutaneous nephrostomy or ureteral stenting is mandatory, with definitive stone treatment delayed until sepsis resolves. 2

Special Consideration for Uric Acid Stones

For uric acid stones, oral chemolysis with alkalinization using citrate or sodium bicarbonate is strongly recommended, targeting urine pH 7.0-7.2, with an approximately 80.5% success rate. 2

Common Pitfalls to Avoid

• Do not restrict dietary calcium, as this paradoxically increases stone risk 4
• Do not offer prolonged conservative management beyond 6 weeks without reassessment 2
• Avoid calcium supplements, which increase stone risk unlike dietary calcium 4
• Do not use routine stenting before shock wave lithotripsy, as it provides no benefit and causes frequent stent-related symptoms 2