ABSTRACT
The purpose of this study is to evaluate the effect of fluid and diet restriction in fasting on biochemical factors of stone formation. Our study concerns 90 patients divided in three groups: healthy fasting patient [G1], healthy non fasting patient [G2] and non fasting patient with calcium lithiasis [G3]. The promotors [oxalate calcium, uric. acid, phosphates] and inhibitors [citrate, magnesium] are statistically significant between G1,G2 and G3,G2. Supersaturation of urine with oxalate, uric acid and brushite are the same for [G1] and [G3] and higher than [G2]. Crystalluria is more important in lithiasis subjects compared with healthy non fasting patients [58% vs 11,4%]. Oxalate monohydrate [Whewellite] and uric crystal don't exist in the healthy non fasting people but reached 4% and 12% respectively in the lithiasis patient. The crystalluria profile is the same in the healthy fasting patients and calcium lithiasis patients. However healthy patients have equilibria between promotors and inhibitors of crystal formation which minimize the risk of crystalluria and subsequent stone formation