What is the appropriate treatment for a patient actively passing a urinary stone?

Treatment for a Patient Actively Passing a Urinary Stone

For patients with uncomplicated ureteral stones ≤10 mm who are actively passing a stone, offer medical expulsive therapy with an alpha-blocker (tamsulosin 0.4 mg daily) combined with NSAIDs for pain control, and continue observation for up to 4 weeks maximum before proceeding to definitive intervention. 1, 2

Initial Assessment and Patient Selection

Before initiating conservative management, confirm the patient meets all eligibility criteria:

• Pain must be adequately controlled with oral analgesics (NSAIDs as first-line) 2
• No clinical evidence of sepsis or fever – check vital signs and obtain urine culture 2
• Normal renal function – verify serum creatinine is within normal limits 2
• No signs of bilateral obstruction or solitary kidney with obstruction 2

Medical Expulsive Therapy Protocol

Alpha-Blocker Therapy

• Prescribe tamsulosin 0.4 mg once daily for distal ureteral stones 5-10 mm, which increases spontaneous passage rates by an absolute 29% compared to placebo (from 54% to 77%) 1, 3
• Counsel patients that this is off-label use and discuss potential side effects including dizziness, orthostatic hypotension, and retrograde ejaculation 2, 3
• Tamsulosin works equally well in both men and women through alpha-1 receptor blockade causing ureteral smooth muscle relaxation 3

Pain Management

• NSAIDs (diclofenac 50-100 mg or ibuprofen) are first-line analgesics – prescribe at the lowest effective dose 2, 4
• Reserve opioids for second-line use when NSAIDs are contraindicated or insufficient 2
• Avoid NSAIDs in patients with significantly reduced GFR 2

Monitoring During Conservative Management

• Perform weekly imaging (low-dose CT or ultrasound) to assess stone position and degree of hydronephrosis 2, 4
• Maximum duration of medical expulsive therapy is 4 weeks – beyond this point, spontaneous passage likelihood declines markedly and risk of irreversible renal damage increases 2, 3
• Most stones that pass spontaneously do so within 17 days (range 6-29 days) 4

Absolute Indications for Immediate Intervention

Stop conservative management and proceed to emergency decompression (percutaneous nephrostomy or ureteral stenting) if any of the following develop:

• Sepsis with obstructed kidney – this is a urologic emergency 2, 4
• Anuria or acute renal failure 2
• Uncontrolled pain despite adequate analgesia 2, 4
• New fever or signs of infection 2
• Progressive hydronephrosis on follow-up imaging 2

Definitive Surgical Treatment After Failed MET

When to Intervene

• If the stone has not passed by week 4, offer definitive surgical treatment without further delay – prolonged obstruction beyond 4-6 weeks risks irreversible kidney injury 2, 3

First-Line Surgical Option

• Ureteroscopy (URS) is the preferred first-line surgical approach for distal ureteral stones after failed MET, achieving stone-free rates of 94-95% for stones <10 mm 2, 4
• URS is especially effective for ureterovesical junction stones due to direct visualization and high success rates 2

Alternative Surgical Option

• Shockwave lithotripsy (SWL) is an acceptable alternative with stone-free rates of 80-87% for ureteral stones <10 mm 2, 4
• SWL may be less effective for UVJ stones due to poor visualization with ultrasound-based lithotripters 2
• Do not routinely place ureteral stents before SWL 4

Stone Size-Specific Recommendations

Stones ≤5 mm

• Spontaneous passage rate is approximately 62-68% without any therapy 3, 4
• Tamsulosin still provides benefit with an absolute 29% increase in passage rates 3, 4

Stones 5-10 mm

• Tamsulosin provides the greatest benefit in this size range – number needed to treat is 4-5 3
• Reduces time to stone expulsion by approximately 3 days and decreases pain episodes 3

Stones >10 mm

• Proceed directly to urologic intervention (URS or SWL) rather than attempting MET, as spontaneous passage rates are very low (≈47%) and complication risk is high 3, 4

Special Populations and Considerations

Patients on Anticoagulation

• Select URS as first-line therapy rather than observation or SWL in patients with uncontrolled bleeding diatheses or those requiring continuous anticoagulation/antiplatelet therapy 2

Uric Acid Stones

• Combine tamsulosin with urinary alkalinization (citrate or sodium bicarbonate to achieve pH 7.0-7.2) for improved passage rates, with success rates of 80.5% 3, 4

Critical Pitfalls to Avoid

• Never exceed 4-6 weeks of conservative management – complete unilateral ureteral obstruction beyond 6 weeks risks irreversible kidney injury 2, 3
• Never attempt stone removal in the presence of purulent urine – instead place a ureteral stent or percutaneous nephrostomy, obtain cultures, and defer definitive treatment until infection resolves 2
• Never perform blind stone basket retrieval without endoscopic visualization – this significantly increases the risk of ureteral injury 2, 4
• Always obtain urine culture before any urologic intervention to prevent urosepsis associated with untreated bacteriuria 4

Comparative Effectiveness: Tamsulosin vs. Nifedipine

• Tamsulosin is significantly superior to nifedipine for medical expulsive therapy, providing a 16-20% absolute increase in stone-passage rates 3
• Nifedipine provides only a marginal 9% improvement over placebo and is not statistically significant 3, 4
• Alpha-blockers achieve overall passage rates of 81-87% compared to 75% with calcium-channel blockers 2, 3