What is the management for a patient with calcium oxalate, significant hematuria, and leukocyturia, indicating a possible kidney stone and urinary tract infection?

Management of Calcium Oxalate Stones with Hematuria and Leukocyturia

Treat the suspected urinary tract infection immediately with appropriate antibiotics while simultaneously initiating acute stone management and long-term prevention strategies. 1

Immediate Management

Infection Control

• Obtain urine culture immediately before starting antibiotics, as the combination of leukocyturia with a calcium oxalate stone suggests either concurrent UTI or stone-related inflammation 1
• Start empiric antibiotic therapy while awaiting culture results, particularly if there are systemic signs of infection 2
• Note that calcium oxalate stones themselves can harbor bacteria and serve as a nidus for recurrent infections, even though they are not classic "infection stones" like struvite 2

Acute Stone Management

• Provide adequate analgesia and hydration for symptomatic stone passage 3
• Approximately 90% of stones causing renal colic pass spontaneously 3
• Strain all urine to capture the stone for analysis - stone composition analysis should be obtained at least once 1
• Monitor for high-grade obstruction or failure of oral analgesics, which may require hospitalization 3
• A urinary tract infection with obstruction is a urologic emergency requiring immediate drainage, usually with ureteral stent 3

Long-Term Prevention Strategy

First-Line Dietary Interventions (All Patients)

Fluid Intake:

• Increase fluid intake to achieve at least 2.5 liters of urine output daily - this is the single most important intervention 4, 5, 6
• Encourage water, coffee, tea, beer, and wine 5
• Avoid grapefruit juice (increases stone risk by 40%) and sugar-sweetened beverages 5

Dietary Modifications:

• Maintain normal dietary calcium intake of 1,000-1,200 mg daily from food sources - never restrict calcium as this paradoxically increases stone risk 4, 6
• Limit sodium to 2,300 mg (100 mEq) daily to reduce urinary calcium excretion 4, 6
• Reduce animal protein to 5-7 servings of meat, fish, or poultry per week 4, 5
• Limit oxalate-rich foods (spinach, nuts, chocolate) only if 24-hour urine shows elevated oxalate 4, 6

Metabolic Evaluation (Essential for All Recurrent Stone Formers)

Initial Testing:

• Obtain one or two 24-hour urine collections measuring: volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 1, 6
• Serum chemistries: calcium, phosphate, uric acid, creatinine 1, 6
• Check serum intact parathyroid hormone if primary hyperparathyroidism is suspected (elevated or high-normal serum calcium) 1

Pharmacologic Management (Based on 24-Hour Urine Results)

For Hypercalciuria (>200 mg/day):

• Offer thiazide diuretics (hydrochlorothiazide 25 mg twice daily or 50 mg once daily, chlorthalidone 25 mg once daily, or indapamide 2.5 mg once daily) 1
• Potassium supplementation is often needed to prevent hypokalemia 1, 6
• Continue dietary sodium restriction to maximize hypocalciuric effect 1

For Hypocitraturia (<320 mg/day):

• Offer potassium citrate 30-100 mEq/day to increase urinary citrate 1, 5, 6
• Use potassium citrate, NOT sodium citrate - sodium load increases urinary calcium excretion 1, 4

For Hyperuricosuria (>800 mg/day) with Normal Urinary Calcium:

• Offer allopurinol to reduce calcium oxalate stone formation 1, 5
• Hyperuricemia is not required for allopurinol therapy 1

Follow-Up Monitoring

• Obtain single 24-hour urine specimen within 6 months of initiating treatment to assess response 1, 6
• Target urine volume >2 liters/day and urinary citrate >320 mg/day 5
• Annual 24-hour urine collection thereafter to assess adherence 6
• Periodic blood testing is mandatory for patients on pharmacologic therapy: monitor for hypokalemia and glucose intolerance with thiazides, hyperkalemia with potassium citrate 6

Critical Pitfalls to Avoid

• Never restrict dietary calcium - this increases urinary oxalate absorption and stone risk 4, 6
• Never recommend calcium supplements over dietary calcium - supplements increase stone risk by 20% compared to food sources 4
• Never use sodium citrate instead of potassium citrate - the sodium load worsens hypercalciuria 1, 4
• Do not ignore the infection component - calcium oxalate stones can harbor bacteria and require complete treatment 2
• Do not recommend vague "eight glasses of water per day" - use specific 24-hour urine volume targets of >2.5 liters 5