Kidney Stones Symptoms and Causes
Kidney stones are solid pieces of material that form from crystallization of excreted substances in the urine. A kidney stone may remain in the kidney or break loose and travel down the urinary tract. A small stone may pass all the way out of the body, but a larger stone can get stuck in a ureter, the bladder or the urethra. This may block the flow of urine and cause great pain. A kidney stone may be as small as a grain of sand or as large as a pearl, and some are as big as golf balls. They may be smooth or jagged, and are usually yellow or brown in color.