There are different types of kidney stones. The exact cause depends on the type of stone.
- Calcium stones are most common. They occur more often in men than in women, and usually appear between ages 20 - 30. They are likely to come back. Calcium can combine with other substances, such as oxalate (the most common substance), phosphate, or carbonate to form the stone. Oxalate is present in certain foods. Diseases of the small intestine increase the risk of forming calcium oxalate stones.
- Cystine stones can form in people who have cystinuria. This disorder runs in families and affects both men and women.
- Struvite stones are mostly found in women who have a urinary tract infection. These stones can grow very large and can block the kidney, ureter, or bladder.
- Uric acid stones are more common in men than in women. They can occur with gout or chemotherapy.