Calcium Nephrolithiasis

1. See Also
   1. Nephrolithiasis
   2. Nephrolithiasis Risk Factors
2. Epidemiology
   1. Represents more than 75% of Nephrolithiasis cases
3. Evaluation: General
   1. Do not perform evaluation during hospitalization
   2. Single Stone episodes with no residual stones
      1. Serum Calcium
      2. Consider 24 hour urine
         1. Urine volume
         2. Urine Calcium
   3. Recurrent (1 stone per 3 years or more), Residual or Family History of stones
      1. Urine Volume
      2. Conside Creatinine Clearance
      3. Urine Calcium (Hypercalciuria >300 mg/day)
      4. Urine Sodium
      5. Urine Uric Acid (Hyperuricosuria >750 mg/day)
      6. Urine Oxalate (Hyperoxaluria >40 mg/day)
      7. Urine Citrate (Hypocitraturia <320 mg/day)
4. Evaluation: Stone Type
   1. Mixed Calcium Oxalate and Phosphate (See above)
      1. Hypercalciuria (50%)
      2. Low urine volume (30-50%)
      3. Hyperoxaluria (20-30%)
      4. Hypocitraturia (20-30%)
      5. Hyperuricosuria (20%)
   2. Pure Calcium Phosphate Stones (uncommon)
      1. Causes
         1. Pregnancy (account for up to 75% of Nephrolithiasis in pregnancy)
         2. Distal Renal Tubular Acidosis
         3. Primary Hyperparathyroidism
         4. Excessive alkalinization
         5. Sarcoidosis
      2. Obtain Serum Electrolytes
         1. Hyperkalemia
         2. Serum Bicarbonate increased
         3. Hyperchloremia
5. Evaluation: Specific Populations
   1. Hmong patients more commonly have increased Uric Acid
   2. African americans rarely form calcium stones
      1. Evaluate if Hypercalciuria and Hypercalcemia
      2. Underlying causes
         1. Sarcoidosis
         2. Primary Hyperparathyroidism
6. Management: Calcium Oxalate Stones
   1. See Nephrolithiasis
   2. Increase fluid increase >2.5 Liters per day
   3. Check Serum Vitamin D and replace if deficiency
   4. Hypercalcemia
      1. Obtain Parathyroid Hormone to evaluate for Hyperparathyroidism
   5. Normocalcemia and uncomplicated calcium stone disease
      1. Normocalciuria
         1. Potassium Citrate (Urocit-K) 20 meq PO tid with meals
      2. Hypercalciuria (>250 mg/day)
         1. Increase Dietary Calcium >1000 mg/day
            1. Take calcium only with meals
            2. Take calcium as food not calcium supplement
         2. Follow low sodium diet (<150 meq/day)
         3. Decrease dietary meat intake
         4. Avoid Loop Diuretics (e.g. Lasix)
         5. Alkaline citrate 9-12 grams/day
         6. Medications: Thiazide Diuretic with potassium
            1. Hydrochlorothiazide 25 to 50 mg PO daily and
            2. Potassium supplement
               1. Normocitraturia:
                  1. Potassium chloride
               2. Hypocitraturia:
                  1. Potassium citrate 20 meq PO tid
   6. Hyperoxaluria
      1. Mild Hyperoxalauria (40-60 mg/day)
         1. Normal Dietary Calcium
         2. Low Oxalate Diet
         3. Decrease Ascorbic acid <1-2 grams/day
      2. Enteric Hyperoxaluria (60-80 mg/day)
         1. Calcium Supplements with meals
         2. Magnesium 200-400 mg/day
         3. Low Fat Diet
         4. Trial of Cholestyramine 2-4 grams per meal
      3. Primary Hyperoxaluria (>80 mg/day)
         1. Trial Pyridoxine (Vitamin B6)
         2. Monitor Renal Function frequently
         3. Referral to Hepatology
7. Management: Calcium Phosphate Stones
   1. Pregnancy Test if not already done
   2. Acidify urine
      1. Cranberry juice 16 ounces daily
   3. Decrease dietary phophate intake by one third
      1. Dairy products
      2. Legumes
      3. Chocolate
      4. Nuts
8. Prognosis
   1. Recurrence risk within 2 years: 35%
9. References
   1. Mobley (Feb 1999) Hospital Medicine, p. 21-38
   2. Goldfarb (1999) Am Fam Physician 60(8): 2269-76
   3. Houshiar (1996) Postgrad Med 100(4): 131-8
   4. Frassetto (2011) Am Fam Physician 84(11): 1234-42
   5. Pietrow (2006) Am fam Physician 74(1): 86-94
   6. Preminger (2007) J Urol 178(6): 2418-34
   7. Portis (2001) Am Fam Physician 63(7):1329-38
   8. Segura (1997) J Urol 158:1915-21
   9. Teichman (2004) N Engl J Med 350:684-93
   10. Trivedi (1996) Postgrad Med, 100(6): 63-78