These are stony masses of minerals and organic matter that form in kidneys . They are produced when mineral salt in urine come out of solution as solid crystals . This may occur when the intake of water is low the salt intake is high or the urine is abnormally acidic or alkaline .
Kidney stones vary in size from tiny sand like grains to large masses which can completely fill the renal pelvis . Large stones may block the flow of urine and cause infection to begin . The pressure that builds up causes severe pain and damages the kidney tubules. Kidney stones may be dissolved by medicine . Large stones may have to be removed surgically.
