Robert Sterling Hollabaugh, Jr. M.D., FACS
Kidney stones form when the concentration of calcium salts and various other chemicals in the urine gets too high. Crystals precipitate in the urine and then aggregate to form stones. While usually a slow process taking months or even years, stones can sometimes form in just a few weeks.
Urinary stones become symptomatic when they cause bleeding or obstruction to the flow of urine. Small stones in the kidney will often not show symptoms. However, when the stones significantly increase in size or pass out of the kidney into the tube (ureter) carrying urine to the bladder, the stone may block the flow of urine, causing pain. Stones may also cause irritation of the lining of the urinary tract resulting in the frequent urge to go, as well as burning with urination.
Kidney stones can affect both men and women, and can occur at any age; although they are most common in middle-aged men.