What is the treatment for a 14-year-old female with a kidney stone?

Treatment of Kidney Stone in a 14-Year-Old Female

The cornerstone of treatment is aggressive hydration to achieve at least 2.5 liters of urine output daily, combined with dietary modifications including normal calcium intake (1,000-1,200 mg/day from food), sodium restriction to 2,300 mg daily, and avoidance of sugar-sweetened beverages. 1, 2

Immediate Management

Acute Stone Episode

• Pain control with NSAIDs as first-line therapy for renal colic, with opioids reserved for severe uncontrolled pain 2
• Increase fluid intake immediately and strain urine to capture any passed stones for analysis 2
• Obtain imaging (ultrasound preferred in pediatric patients due to radiation concerns, or non-contrast CT if needed) to confirm diagnosis and assess stone size/location 2
• Seek emergency care if fever, signs of infection, severe uncontrolled pain, vomiting with dehydration, or urinary obstruction develops 2

Initial Diagnostic Workup

• Obtain stone analysis at least once when stone material is available to guide prevention strategies 1, 2
• Perform urinalysis with both dipstick and microscopic evaluation to assess pH, hematuria, infection, and crystal type 2
• Check serum chemistries including electrolytes, creatinine, and uric acid 2
• Obtain serum intact parathyroid hormone if serum calcium is high or high-normal to exclude primary hyperparathyroidism 1

Long-Term Prevention Strategy

Fluid and Dietary Management (First-Line for All Stone Types)

Hydration Protocol:

• Mandate fluid intake sufficient to produce at least 2.5 liters of urine daily (typically requires 3+ liters of oral intake) 1, 2
• This single intervention reduces stone recurrence by approximately 50% (12.1% vs 27.0% recurrence) 1
• Encourage water, coffee, tea, and orange juice; these beverages are associated with lower stone risk 1, 2
• Strictly avoid sugar-sweetened beverages, particularly colas acidified with phosphoric acid, which increase stone risk 1, 2

Dietary Modifications:

• Maintain normal dietary calcium at 1,000-1,200 mg daily from food sources (dairy, fortified foods, leafy greens) 1, 2, 3
  • Critical pitfall to avoid: Never restrict dietary calcium—this paradoxically increases stone risk by increasing intestinal oxalate absorption 2, 3
  • A normal calcium diet (1,200 mg/day) reduces recurrence by 51% compared to low calcium diet (400 mg/day) 3
• Limit sodium intake to 2,300 mg (100 mEq) daily to reduce urinary calcium excretion 1, 2, 3
• Reduce animal protein intake (limit to 5-7 servings of meat, fish, or poultry per week), as animal protein increases urinary calcium and reduces citrate 3
• Avoid calcium supplements (like Tums), which increase stone risk by 20% compared to dietary calcium 3
• Limit oxalate-rich foods (spinach, nuts, chocolate, tea) only if documented hyperoxaluria exists on metabolic testing 1, 2, 3

Metabolic Evaluation for Recurrent or High-Risk Stone Formers

Indications for 24-Hour Urine Testing:

• Recurrent stone formation 1
• First-time stone former who is high-risk (solitary kidney, large stone burden, young age like this 14-year-old) 1
• Multiple or bilateral renal calculi 1

Testing Protocol:

• Collect one or two 24-hour urine samples on a random diet (two collections preferred) 1, 3
• Measure: total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine 1, 3
• If cystine stones suspected or family history of cystinuria, add urinary cystine measurement 1

Pharmacologic Therapy (When Dietary Measures Fail)

The American College of Physicians recommends pharmacologic monotherapy only after increased fluid intake fails to prevent recurrent stones. 1

For Calcium Stones with Specific Metabolic Abnormalities:

• Thiazide diuretics for high or relatively high urinary calcium:

  • Hydrochlorothiazide 25 mg twice daily or 50 mg once daily 1
  • Chlorthalidone 25 mg once daily 1
  • Indapamide 2.5 mg once daily 1
  • Continue dietary sodium restriction to maximize hypocalciuric effect 1
  • Monitor for hypokalemia; may require potassium supplementation 1
  • Reduces stone recurrence (24.9% vs 48.5% with placebo) 1

• Potassium citrate for low or relatively low urinary citrate:

  • Critical: Use potassium citrate, NOT sodium citrate—sodium increases urinary calcium excretion 3
  • Reduces stone recurrence (11.1% vs 52.3% with placebo) 1
  • Also beneficial for calcium phosphate stones and those with low urinary pH 1

• Allopurinol for hyperuricosuria (>800 mg/day) with normal urinary calcium:

  • Reduces recurrence (33.3% vs 55.4% with placebo) 1
  • Specifically for calcium oxalate stones with elevated uric acid excretion 3

Special Considerations for Pediatric/Adolescent Patients

• Young age at first stone episode (14 years old) places this patient at high risk for recurrence, warranting aggressive preventive measures 1
• Metabolic testing is particularly important in pediatric stone formers to identify underlying disorders 1
• Ensure adequate calcium intake for bone health during adolescence while preventing stones 2, 3
• Consider family history screening, as genetic factors play a significant role in pediatric nephrolithiasis 2

Follow-Up Monitoring

• Repeat imaging to quantify stone burden and assess for new stone formation 1
• If on pharmacologic therapy, monitor blood chemistry for electrolyte abnormalities 1
• Consider repeat 24-hour urine collection to assess treatment efficacy, though evidence for routine monitoring is insufficient 1