[Fundamental bases of urinary oxalo-calcic lithogenesis]

Oxalo-calcic lithogenesis is a multifactorial and complex phenomenon leading to the formation of stones from crystals which originate, grow and agglomerate in the urinary tract. The over-saturation of calcium oxalate in the urine is a fundamental element of the processus which goes through successive stages under the influence of promoting or inhibiting agents. The coefficient of over-saturation corresponds to the ratio of ioniclly active products and the thermodynamic solubility and depends not only on the type of crystal but also on the surrounding environment, in particular its ionic force. Crystals of uric acid, sodium urate and brushite urate are the main activators of oxalo-calcic lithogenesis and cirate, magnesium and pyrophosphates and different protein compounds (nephrocalcin, Tam-Horsfall protein) are the main inhibitors. These pathophysiologic features have a direct effect on adapted prophylactic management of the often recurrent oxalo-calcic urinary lithiasis.