The crystal nidus of brushite (nidus of renal stones containing calcium) cannot form when the activity product (state of saturation) of brushite in urine is less than the formation product (the lowest state of supersaturation supporting nucleation). Treatment measures should therefore be directed at reducing the activity product or increasing the formation product. The response to treatment with cellulose phosphate and with sodium phosphate was evaluated according to this criterion. Cellulose phosphate decreased the activity product while slightly increasing or not significantly affecting the formation product. Sodium phosphate increased both the activity product and the formation product of brushite. The formation product increased largely as the result of the increase in urinary pyrophosphate. In most patients, the increase in the activity product during treatment with sodium phosphate was fully compensated by the increase in the formation product.
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism