Small masses of solid matter that have separated out of urine are fairly common in the Urinary Tract. A renal Calculus (a stone formed in the kidney) is more difficult to get at and remove than other urinary-tract stones. Kidney stones vary in size and shape from tiny particles like grains of sand to large, branched formations filling much of the space in the kidney. Very small particles may be voided without a person's knowing it. Larger stones may cause intense pain and damage if they leave the kidney and pass through the urinary tract. They may also block the ureter and prevent urine from leaving the kidney. Stones too large to enter the ureters may cause serious mechanical damage to the delicate tissues surrounding them.
Any kidney stone that causes trouble may lead to serious complications. It must be removed as soon as possible, usually by surgery. Some persons have a tendency to form stones repeatedly. By making a thorough medical examination including, if possible a chemical voided or removed the doctor can sometimes identify the cause in a particular case.
The doctor may prescribe a special diet or medicine to help prevent stone formation, once the cause has been determined. Frequently, treatment includes drinking larger amounts of water than usual, so that the urine is kept dilute enough to hold all dissolved salts in solution and keep them from forming a hard mass.