PAUL MONIZ: Dr. Marks, what about the stones themselves? How big can they get and how long does it take for them to form?
JON MARKS, MD: That varies with the composition of the stone. There are a number of different kinds of stones. Calcium stones are the most common, about 85 percent of stones. But, the calcium can exist in combination with other substances: phosphates, oxylates. Stones can also be uric acid. The uric acid stones perhaps develop the most quickly, and as a result, can be treated by being dissolved with medication very often. But the calcium stones sometimes take years to form.
PAUL MONIZ: Dr. Marks, can you show us in the diagram that you have there exactly where the stones form?
JON MARKS, MD: This entire diagram is meant to illustrate a number of different pathologies. So in this particular case, this is a stone that's the size of a Rice Krispie or perhaps a little bit smaller. A stone can be the size of a BB located in this location, set up some local inflammation or some swelling as a result of the motion down through the ureter and cause a great deal of pain.
PAUL MONIZ: Dr. Salant, maybe we can see the stone again as you describe the kind of pain that someone might suffer, and also other symptoms like fever, etc.
ROBERT SALANT, MD: This is rather large stone called a staghorn stone. This is a stone that formed in the area of the kidney called the collecting system. This stone was removed surgically, and this is the entire stone. A stone like this is usually associated with kidney infections, and it forms because of chronic infection.
PAUL MONIZ: You have some other stones there; maybe we could look at those as well as you continue.
ROBERT SALANT, MD: These are examples of stone fragments that were obtained after a larger stone was treated by breaking the stone up into smaller pieces which were then able to pass down the ureter and out through the body causing much less blockage and much less pain.
PAUL MONIZ: These will be passed out through someone's urine?
ROBERT SALANT, MD: Absolutely.
PAUL MONIZ: These are rather large pieces to pass through someone's urethra. Would it be extremely painful for that to pass through someone's urethra?
ROBERT SALANT, MD: In fact, the answer is: The narrowest part of the urinary track is the area where the tube calls the ureter enters into the bladder. Once a stone passes that narrow point and enters the bladder, it's no longer creating blockage and therefore, no longer creating pain. The remainder of the passage out through the body usually occurs without much difficulty. A patient may feel this come out, but is usually able to urinate a stone this size out.
PAUL MONIZ: Dr. Salant, what are the dangers of just not doing anything and just living with the pain, so to speak?
ROBERT SALANT, MD: Most stones can be relatively asymptomatic and relatively pain free. Probably 80 percent of stones do not need to be removed or treated. However, in the stones that are symptomatic, they can lead to several things. Number one, the stone may continue to grow, which may lead to obstruction, which can lead to pain, fever and infection. The stones may also lead to kidney damage if they go untreated for a long period of time.
PAUL MONIZ: So it's important that people keep tabs on those symptoms and get to their doctor if they're unsure?
ROBERT SALANT, MD: Absolutely, if there's any question, just get evaluated. You may be pleasantly surprised and find that you don't need to be treated. Usually the initial step is just hydration.
PAUL MONIZ: Very good information. Dr. Robert Salant, thank you for your time. Dr. Jon Marks, for your time as well. I'm Paul Moniz. Thank you for joining us. Remember that kidney stones are common, affecting about 10 percent of the American population at one point or another. Thanks for being with us.