Idiopathic calcium oxalate urolithiasis: risk factors and conservative treatment

Idiopathic calcium oxalate urolithiasis is a frequent and recurrent multifactorial disease. This review focuses on urinary and dietary risk factors for this disease and conservative strategies for rectifying them. Dietary oxalate and calcium and their respective urinary excretions have been extensively investigated during the last 10 years. Urinary oxalate has emerged as the most important determinant of calcium oxalate crystallization while the role of urinary calcium has shifted to bone balance and osteoporosis. Dietary calcium restriction increases urinary oxalate and contributes to a negative bone balance. It has therefore been abandoned as a means to reduce the risk of calcium oxalate kidney stone formation. Calcium oxalate kidney stone patients are advised to increase their fluid intake to achieve a urine volume of 2 l or more; the recommended calcium intake is 800-1200 mg/day; high oxalate foods should be restricted; daily protein intake should be between 0.8 and 1 g/kg body weight/day; essential fats should be included; vegetable and fruit (except oxalate-rich vegetables) intake should be increased. The use of calcium supplements has potential benefits but needs to be examined further.