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Nephrolithiasis/Kidney Stones

By Philip E. Gleason, MD

You have probably been told that you have a kidney stone. You are not alone. Approximately 5% of the population will have a kidney stone during their life. Kidney stones represent accumulation of crystals in the urine and ultimate formation of a stone. Typically these are composed entirely of uric acid, which may be related to gout. There is also the possibility that the kidney stone can be formed as a result of urinary tract infections.

As a rule of thumb, if the kidney stone is large enough to cause future problems and is located in the kidney, we would attempt to break this up with extra corporal shock wave lithotripsy (ESWL), which is the kidney stone crushing machine. This uses a shock wave that passes through the body. It passes through the soft tissue of the body without problems. If, however, it hits a hard substance, it will cause the stone to vibrate and to break up into small pieces, which then pass on their own. On other occasions, if the stone is quite large, it may be better to operate on the kidney percutaneously through a small tract through the back or flank.

If the kidney stone is in the ureter passing from the kidney down toward the bladder, it depends how high the kidney stone is when it starts causing problems. If the stone is relatively high in the ureter (toward the kidney), we push the stone back into the kidney and use the ESWL kidney stone crushing machine. If the kidney stone is further down the ureter (toward the bladder), we can sometimes look into the bladder and into the ureter and grasp the stone in a small basket or break it up with a laser and remove it. If the kidney stone is small, it may pass on its own and not require any intervention at all.

Once the kidney stone has passed or been removed, we often try to analyze the kidney stone and evaluate to see if there is any specific metabolic abnormality of the calcium, oxalate, or uric acid metabolism, or as mentioned above, difficulties with UTI's. The hope would be to identify the exact cause of the kidney stone formation and hopefully try to prevent future kidney stones from forming. As a rule of thumb, the most effective way of preventing future kidney stones is to remain well-hydrated and produce a lot of urine which then tends to flush the stone crystals out of the body before they have a chance to form into a stone. We would typically ask you to drink 10-12 glasses of fluid per day. When passing the urine, if it is yellow or dark yellow, this is often a sign thatyou are somewhat dehydrated and the urine fairly concentrated which makes stones more likely to form. We can also sometimes modify the diet to avoid substances that cause kidney stones. Consideration can also be given to using different medications to try to prevent future stone formation.

As a rule, if you have one kidney stone in your life, you have an approximately 50% chance of having a second stone at some point in time. By remaining well-hydrated and following other instructions, hopefully you can prevent any future stones.