Calcium stones are the most common type of kidney stone and occur in two major forms: calcium oxalate and calcium phosphate. Calcium oxalate stones are more common. Calcium oxalate stone formation may be caused by high calcium and high oxalate excretion. Calcium phosphate stones are caused by the combination of high urine calcium and alkaline urine, meaning the urine has a high PH.
Uric acid stones form when the urine is persistently acidic. A diet rich in purines substances found in animal protein such as meats, fish, and shellfish may increase uric acid in urine. If uric acid becomes concentrated in the urine, it can settle and form a stone by itself or along with calcium.
Struvite stones result from kidney infections. Eliminating infected stones from the urinary tract and staying infection-free can prevent more struvite stones.
Cystine stones result from a genetic disorder that
causes cystine to leak through the kidneys and into the urine, forming crystals
that tend to accumulate into stones.