Calcium stones. These are most common and often occur in men. Factors contributing to their formation include dehydration, high calcium levels in the blood or urine, kidney deformities, excess parathyroid hormone, or taking certain medications, such as some diuretics, antacids, or vitamin D. They’re usually combined with oxalate, another substance in urine.
Uric acid stones. These two are more common in men and usually result from consistently concentrated, excessively acidic urine. Excess uric acid in urine may be related to a diet high in meat. High uric acid in the blood or urine can occur if you’re receiving chemotherapy. Elevated concentrations of uric acid in the joints cause gout.
Struvite stones. These form when certain types of bacteria chronically infect the kidneys and increase ammonia content. The result is often large stones that can cause serious kidney damage unless removed.
Cystine stones. Only one percent of stones are of this type. A hereditary disorder causes the kidneys to excrete excessive amounts of certain amino acids (cystinuria).
