What is the management of renal and ureteric stones?

Management of Renal and Ureteric Stones

Initial Evaluation

All patients newly diagnosed with kidney or ureteral stones require a screening evaluation consisting of detailed medical and dietary history, serum chemistries (electrolytes, calcium, creatinine, uric acid), and urinalysis with microscopic examination to assess urine pH, infection indicators, and crystal identification 1, 2.

• Obtain urine culture if urinalysis suggests infection or if recurrent UTIs are present 1, 2
• Measure serum intact parathyroid hormone if primary hyperparathyroidism is suspected (high or high-normal serum calcium) 1
• Obtain stone analysis at least once when available, as composition (uric acid, cystine, struvite) directs specific preventive measures 1
• Review imaging studies to quantify stone burden; multiple or bilateral stones indicate higher recurrence risk 1, 2

Acute Management

Pain Control

NSAIDs (diclofenac 50-100 mg rectally or 75 mg IM, or ibuprofen) are first-line treatment for acute renal colic, with opioids reserved as second-line when NSAIDs are contraindicated or ineffective 3, 4, 5.

• Use NSAIDs at the lowest effective dose due to cardiovascular and gastrointestinal risks, particularly with reduced GFR 4
• If opioids are required, use hydromorphone, pentazocine, or tramadol rather than pethidine due to higher vomiting rates 4

Emergency Situations

In cases of sepsis and/or anuria with obstructed kidney, perform urgent decompression via percutaneous nephrostomy or ureteral stenting immediately; delay definitive stone treatment until sepsis resolves 3, 4.

Medical Expulsive Therapy

Alpha-blockers (tamsulosin) are recommended for medical expulsive therapy, particularly for distal ureteral stones >5 mm 4.

• Stones <5 mm typically pass spontaneously 6, 5
• Stones 5-10 mm may pass with medical management but up to 50% require intervention 5
• Stones >10 mm are unlikely to pass spontaneously and require urology consultation 5

Surgical Management

Ureteral Stones

Ureteroscopy (URS) is the primary surgical treatment for ureteral stones, offering better stone-free rates than ESWL for most locations 1, 3.

• URS is specifically recommended for patients with bleeding disorders or on anticoagulation 3
• ESWL is appropriate for accessible stones but less effective than URS 1, 3
• Avoid electrohydraulic lithotripsy for ureteral stones 1

Renal Stones

Treatment selection depends on stone size and location:

• Stones <10 mm: URS or ESWL as first-line options 1, 3
• Stones 10-20 mm: URS or ESWL 1
• Stones >20 mm: Percutaneous nephrolithotomy (PCNL) is the standard first-line treatment 1, 3

Preoperative Considerations

• Obtain non-contrast CT to determine optimal surgical intervention 1
• Perform urinalysis and/or urine culture prior to surgery to rule out UTI 1
• Consider contrast-enhanced studies if collecting system anatomy needs assessment 1
• Routine stenting after uncomplicated URS is unnecessary but recommended with trauma, residual fragments, bleeding, perforation, or UTI 3

Stone-Specific Medical Management

Calcium Stones

Thiazide diuretics are recommended for patients with high or relatively high urine calcium and recurrent calcium stones 1, 4.

• Offer potassium citrate to patients with recurrent calcium stones and low urinary citrate 1, 4
• Offer allopurinol to patients with recurrent calcium oxalate stones who have hyperuricosuria and normal urinary calcium 1, 4

Uric Acid Stones

Potassium citrate to alkalinize urine to pH approximately 6.0 is first-line therapy for uric acid stones 3, 4, 7.

• Do NOT routinely use allopurinol as first-line therapy; most patients have low urinary pH rather than hyperuricosuria as the predominant risk factor 1, 4
• Allopurinol is reserved for hyperuricosuric patients with recurrent stones and/or gout 4, 7
• Uric acid stones can be dissolved with successful urinary alkalinization 7

Cystine Stones

First-line therapy includes increased fluid intake to achieve urine output of at least 3 liters daily, sodium and protein restriction, and potassium citrate to raise urinary pH to approximately 7.0 1, 3, 4.

• Offer cystine-binding thiol drugs (tiopronin) to patients unresponsive to dietary modifications and urinary alkalinization, or those with large recurrent stone burdens 4

Struvite Stones

Complete surgical removal is necessary for struvite stones 3.

• Monitor patients for reinfection after treatment 2

Prevention of Recurrence

Universal Dietary Measures

All stone formers should achieve fluid intake that produces at least 2.5 liters of urine daily 1, 3, 2.

• Alkalinize urine by eating a diet high in fruits and vegetables for calcium oxalate, cystine, and uric acid stones 8
• Acidify urine with cranberry juice or betaine for calcium phosphate and struvite stones 8

Metabolic Testing

Perform additional metabolic testing in high-risk or interested first-time stone formers and all recurrent stone formers 1.

• Obtain one or two 24-hour urine collections (two preferred) on random diet, analyzing for total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 1
• Obtain follow-up 24-hour urine collection within 6 months of initiating treatment to assess response 1, 4, 2
• After initial follow-up, obtain annual 24-hour urine specimens or more frequently depending on stone activity 4

Monitoring

• Perform periodic blood testing to assess for adverse effects in patients on pharmacological therapy 1, 4
• Obtain follow-up imaging to confirm stone clearance and assess for new stone formation 1, 3
• Repeat stone analysis when available, especially in patients not responding to treatment 4

Common Pitfalls

• Do not prescribe allopurinol as first-line therapy for uric acid stones—most patients need urinary alkalinization with potassium citrate, not reduction of uric acid production 1, 4
• Do not neglect metabolic evaluation in recurrent stone formers—identification of specific risk factors directs targeted therapy 1, 4
• Do not use routine stenting after uncomplicated URS—this increases morbidity without benefit 3
• Do not delay urgent decompression in obstructed infected kidneys—this is a urological emergency requiring immediate intervention 3, 4