Stones: Non-Surgical Management

Stone Prevention

Fluid recommendations

Food recommendations

  • Eat less salt: salt reabsorption in the tubule decreases calcium reabsorption, limit salt intake to < 2.3g daily (100mEq)
  • Eat less meat: protein = amino acids -> high urinary acid load, all meat (mammal, bird, fish, etc) are equal, can also increase calcium excretion
  • Oxalate-containing foods: only avoid if proven hyperoxaluria, likely due to enteric causes
  • Vitamin C (absorbic acid): can be converted to oxalate, avoid high doses
  • DASH diet: shown to decrease stone formation despite having increased oxalate content
  • Juice

    Calcium balance

    Management based on metabolic workup parameters

    Dehydration Hypercalcuria Hypercalcemia Hypernatruria Hyperuricosuria Low urinary pH Hypocitraturia Hyperoxaluria Stone composition Other findings Diagnosis Management
    Yes - Dehydration Increase fluid intake to 2-3L
    No Yes Yes No - CaPhos HyperPTH Resorptive hypercalciuria Parathyroidectomy
    No - Hypercalciuria Thiazide diuretic
    Yes Hypernatriuria Limit sodium intake
    No Yes Yes - Calcium - Hyperuricosuria Hydration
    Alkalinization
    Uric acid
    No - Hyperuricosemia Various causes Treat underlying cause
    Allopurinol
    No No Yes - Hypocitraturia KCit supplement
    No (increased) - CaPhos Hypokalemia/Hypochloremia Type I RTA KCit + Hydration
    No Yes - Hyperoxaluria Limit dietary oxalate
    Consider B6 supplement
    No Struvite Urease-splitting bacteria UTI/Struvite stones Complete stone removal
    Acetohydroxamic acid
    Cystine Cystinuria Cystinuria Hydration
    Alkalinization
    Thiola
    Ammonium acid urate Radiolucent Chronic diarrhea Check for chronic diarrhea causes
    Xanthine Xanthinuria Check for mutation vs allopurinol use
    Hypomagnesiuria - Hypomagnesiuria Magnesium supplements
    Calcium Otherwise normal Idiopathic stone formation KCit supplements

    Medications

    Class Mechanism Indication Side effects Dosing
    Thiazide diuretics distal tubule calcium resorption, sodium excretion Hypercalciuria, calcium stones Hypokalemia (may need supplements), hyperuricosuria, hypercalcemia, hyperglycemia, hypocitraturia (secondary to intracellular acidosis), tachyphylaxis HCTZ 25mg BID
    Chlorthalidone 25mg QD
    Indapamide 2.5mg QD
    Potassium citrate (KCit) Increases urinary citrate, alkalinizes urine, binds urinary calcium Calcium stones, low urinary citrate, Type I RTA, chronic diarrhea (use liquid form), thiazide-induced hypocitraturia, HU < 500 GI symptoms, hyperK (requires regular monitoring), increased CaPhos risk, wax coating passes in stool 20mg BID-TID
    Calcium supplements Prevents oxalate absorption, maintains normocalcemia Hypocalcemia, hyperoxaluria - test on and off supplementation Increases calcium stone risk 500-600mg CaCarb BID
    Sodium bicarbonate
    Sodium citrate
    Increases urinary citrate, alkalinizes urine KCit replacement if hyperkalemia risk Hypernatremia 650-1300 mEq QD-BID
    Allopurinol (Zyloprim) Inhibits uric acid production Calcium stones in setting of hyperuricosuria (> 800/day) and normal calcium, do not give for uric acid stones Transaminitis, rash, myalgias
    Check baseline and 1mo LFTs
    300mg daily
    Alpha-mercaptopropionylglycine (Thiola) Inhibits formation of insoluble cystine bond Cystinuria Transaminitis, anemia, asthenia, GI distress, rash 300mg BID, titrate up PRN
    Acetohydroxamic acid (Lithostat) Urease inhibitor Struvite stones that cannot be managed surgically Phlebitis/DVT, hemolytic anemia (3-15%), hypercoagulable state, tremor, headache, rash, palpitations, GI distress, alopecia 250mg BID-TID
    Magnesium oxide Increases calcium and phosphate solubility Hypomagnesiuria Diarrhea, hypermagnesiuria in renal insufficiency 140gmg QID or 400-500mg BID

    References