Table 11.5-2. Treatment of underlying causes of various types of nephrolithiasis

Idiopathic hypercalciuria

Treatment of hypercalciuria

– Diet: normal calcium intake 1-1.2 g/d (note: dietary calcium restriction causes increased intestinal absorption of oxalate and subsequent hyperoxaluria and is also a risk factor for osteoporosis), sodium restriction to 1500 mg/d (65 mmol/d), protein restriction to 0.8-1 g/kg body mass/d; low-sugar meals and drinks

– Thiazide diuretics to inhibit urinary calcium excretion, eg, hydrochlorothiazide 12.5-50 mg/d, chlorthalidone 25 mg/d, indapamide 2.5 mg/d (always combined with potassium supplementation either through a high-potassium diet or as potassium supplements, preferably potassium citrate)

Hypocitraturia

Raising urine pH

Potassium citrate; maintain urine pH in the range 6.4-6.8 (raising urine pH causes increased urinary citrate excretion)

Citrate supplementation

Potassium citrate increases urinary citrate excretion and reduces calciuria

Hyperoxaluria due to increased oxalate intake

Reducing dietary oxalate intake

Low-fat, low-oxalate diet(dietary fats increase oxalate absorption)

Binding oxalate in GI tract

– Normal dietary calcium intake; in case of inadequate dietary calcium intake use calcium supplements (calcium 1-1.5 g/d in divided doses with meals); magnesium supplementation: recommended Mg2+ intake is 21-25 mmol/d in the form of magnesium citrate (with meals; do not use magnesium oxide)

– Cholestyramine (binds oxalate in GI tract)

Primary hyperoxaluria

Pyridoxine 250-1000 mg/d

Increases glyoxylate conversion to glycine (this lowers the amount of glyoxylate available for conversion to oxalate)

Correction of enzyme defect

Liver transplant combined with kidney transplant

Cystine stones

Increasing cystine solubility

– Intake of fluids to maintain urine output >3 L/d; high amounts of fluids should also be consumed at bedtime and nighttime (after every voiding at nighttime patient should drink 300-500 mL of fluids and take an additional dose of urine-alkalizing agents)

– Raising urine pH using potassium citrate; during treatment frequent urine pH monitoring required (self-monitoring using dipstick tests); recommended pH >7.5

– Tiopronin 0.8-1 g/d, penicillamine 1-2 g/d (these agents form soluble cysteine-drug complexes)

Reduction of methionine (source of cystine) intake

Dietary protein restriction to 0.8 mg/kg/d

Struvite stones (associated with infection)

Treatment to achieve sterile urine

Antimicrobial treatment based on results of susceptibility testing

Total removal of stones

ESWL, percutaneous nephrolithotomy

Ensuring adequate urine flow

Correction of anatomic or functional abnormalities of the urinary tract (urinary retention is the main risk factor for recurrent UTIs)

Urease inhibition

Acetohydroxamic acid 12 mg/kg/d; only after all surgical treatment options have been exhausted

Uric acid stones

Reduction of purine intake

Low-purine diet

Raising urine pH

Potassium citrate; recommended pH >6.5

Reduction of uric acid excretion

In patients with hyperuricosuria: allopurinol 100-300 mg/d

a Avoid spinach, rhubarb, soy products, nuts, almonds, chocolate, strong coffee or tea, beetroots, and excess meat.

ESWL, extracorporeal shock wave lithotripsy; GI, gastrointestinal; UTI, urinary tract infection.