Pathophysiology of hypocitraturic nephrolithiasis.

Urinary citrate inhibits calcium stone formation by complexing calcium in a soluble form and by effects on urinary crystals to prevent growth to stones. Low urinary citrate has been recognized for several decades as a contributing factor in some stone forming patients, but recent studies have elucidated the mechanisms and derangements of the renal handling of citrate in various conditions. In addition, oral citrate as an alkalinizing agent can not only increase urinary citrate, but also favorably impact other stone-promoting conditions. This review will focus on the understanding of these concepts.