What is the recommended treatment for an adult patient with kidney stones and no significant medical history?

Treatment of Kidney Stones in Adults Without Significant Medical History

For an adult patient with kidney stones and no significant medical history, begin with a screening evaluation including detailed medical and dietary history, serum chemistries (electrolytes, calcium, creatinine, uric acid), and urinalysis to guide initial management, followed by conservative treatment with increased fluid intake to achieve >2.5 L/day urine output, and proceed to surgical intervention (ureteroscopy or shock wave lithotripsy for stones ≤20 mm, percutaneous nephrolithotomy for stones >20 mm) if conservative measures fail or if the patient has intractable pain, progressive obstruction, or infection. 1, 2

Initial Diagnostic Workup

Perform ultrasound as the first-line imaging modality (45% sensitivity for ureteral stones, 94% specificity), followed by non-contrast CT if ultrasound is inconclusive or more anatomic detail is needed. 3, 1

Obtain the following laboratory tests at initial presentation: 1

• Serum electrolytes, calcium, creatinine, and uric acid to identify underlying metabolic conditions
• Urinalysis with both dipstick and microscopic evaluation to assess urine pH, detect infection, and identify pathognomonic crystals
• Urine culture if urinalysis suggests infection or if the patient has recurrent UTIs

Collect a detailed dietary history focusing on: 1

• Daily fluid intake (amount and specific beverages)
• Protein intake (types and amounts)
• Calcium, sodium, and high oxalate-containing foods
• Fruits, vegetables, and over-the-counter supplements

Acute Pain Management

Administer NSAIDs (diclofenac, ibuprofen, or metamizole) as first-line analgesics for renal colic, with opioids reserved as second-choice if NSAIDs are contraindicated or insufficient. 3, 1

Conservative Management Strategy

Fluid Therapy

Increase fluid intake to achieve a minimum urine output of 2-2.5 liters daily, which reduces stone recurrence by approximately 50%. 2, 1 Water is the preferred beverage, though coffee, tea, beer, and wine also reduce stone formation risk. 2 Avoid grapefruit juice as it increases stone risk by 40%. 2

Dietary Modifications

Implement the following dietary changes: 2, 3

• Maintain normal dietary calcium intake (1,000-1,200 mg/day)—do not restrict calcium
• Restrict dietary sodium to ≤2,300 mg/day
• Reduce animal protein to 5-7 servings of meat, fish, or poultry per week
• Increase fruits and vegetables to counterbalance acid load and raise urinary pH

Medical Expulsive Therapy

For uncomplicated distal ureteral stones ≤10 mm, consider alpha-blockers to facilitate spontaneous stone passage, particularly for stones >5 mm in the distal ureter. 3, 4

Indications for Surgical Intervention

Urgent/Emergent Indications

Proceed immediately to emergency decompression via percutaneous nephrostomy or ureteral stent if: 1, 5, 3

• Obstructing stone with suspected infection or sepsis
• Anuria with obstructed kidney
• Solitary kidney with obstruction

Symptomatic Indications for Active Stone Removal

Offer surgical intervention for: 5, 3

• Intractable pain despite medical management
• Progressive hydronephrosis or declining renal function
• Urinary tract infection with obstruction
• Stone growth on follow-up imaging
• Failure of conservative management beyond 4-6 weeks (to prevent irreversible kidney injury)

Stone Size-Based Treatment Algorithm

For stones ≤20 mm (non-lower pole): 5, 1

• Offer shock wave lithotripsy (ESWL) or ureteroscopy (URS) as first-line options
• URS has lower likelihood of requiring repeat procedures and achieves stone-free status more quickly than ESWL

For lower pole stones ≤10 mm: 5

• Both ESWL and URS are appropriate with no significant difference in stone-free rates

For lower pole stones >10 mm: 5

• Do not offer ESWL as first-line therapy
• Prefer URS or percutaneous nephrolithotomy (PCNL)

For stones >20 mm: 5, 1

• Offer PCNL as first-line therapy (achieves 94% stone-free rates vs 75% for URS)
• Do not offer ESWL as first-line due to significantly reduced stone-free rates

Metabolic Evaluation for Prevention

For first-time stone formers without high-risk features, the initial screening evaluation is sufficient. 1 However, comprehensive metabolic testing with 24-hour urine collection is indicated for: 3, 1

• High-risk first-time stone formers (multiple or bilateral stones, nephrocalcinosis)
• Recurrent stone formers
• Stones composed of uric acid, cystine, or struvite

The 24-hour urine collection should analyze: 3

• Total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine

Pharmacologic Prevention (Based on Metabolic Testing)

If comprehensive metabolic testing reveals specific abnormalities, initiate targeted pharmacotherapy: 2, 1

• For hypercalciuria (>200 mg/day): Thiazide diuretics—hydrochlorothiazide 50 mg, chlorthalidone 25-50 mg, or indapamide 2.5 mg daily
• For hypocitraturia (<320 mg/day): Potassium citrate 30-100 mEq/day, targeting urinary pH 6.0-6.5
• For hyperuricosuria (>800 mg/day in men, >750 mg/day in women) with normocalciuria: Allopurinol

Follow-Up Monitoring

Obtain a 24-hour urine collection at 6 months to verify adequate urine volume (>2 liters/day) and assess metabolic parameters. 2 Monitor urinary pH to ensure it remains between 6.0-6.5 and does not exceed 7.0. 2

Critical Pitfalls to Avoid

• Do not delay intervention beyond 4-6 weeks for stones requiring treatment, as this risks irreversible kidney injury. 5
• Always obtain urinalysis and urine culture before intervention to identify unrecognized infection. 5
• Do not restrict dietary calcium, as this paradoxically increases stone risk by allowing more intestinal oxalate absorption. 2, 3
• Do not direct patients who already drink recommended fluid amounts to increase fluids further, especially if contraindications exist. 2
• Do not fail to obtain stone analysis when available, as this guides prevention strategies. 3