Why Do Kidney Stones Hurt So Much?

A kidney stone attack is described as the most painful experience it's possible to live through. It's more painful than gunshot wounds, major surgery, broken bones, burns and even childbirth. The pain is unrelated to the size of the stone and is not caused by the stone "moving" or scratching as many people think. In fact, the pain is caused by the stretching and spasm of the urinary system caused by the blockage the stone produces when it gets stuck. When the urine that the kidney produces cannot pass the blockage, the urinary system stretches. This stretching is what causes the intense pain. (The same process causes the pain from intestinal gas that we all get from time to time.) This also explains why the stones don't hurt when they are just sitting inside the kidney. Since they don't produce any blockage or stretching of the urinary system, they do not usually produce any pain until they leave the kidney and get stuck. The degree of pain is unrelated to the size of the stone so even tiny stones can cause terrible pain.

What Are My Chances Of Having Another Stone Attack?

If there are no additional stones in your kidneys now and this was your first stone attack, then your chances of forming another stone is about 10% a year although this will vary according to the specific chemical problems that are involved with each individual patient. Younger patients and those with a close family member or blood relative with stones are at greater risk. In Lorain County, the risk of having another stone problem if you've just had your first stone attack is about 75 %. Conservative treatment measures such as dietary moderation and increasing fluid intake can reduce recurrences by about 60 %. Metabolic studies, which include comprehensive blood and urine testing together with a specific treatment plan, can reduce the risk of new stone formation by up to 98 %!

Will My Stone Pass Without Surgery?

If the stone is smaller than 5 mm or about 1/4 inch in diameter, then it will probably pass without surgery. Should your stone be greater than 10 mm in size, then it almost certainly will not pass. Stones that are between 5 and 10 mm may pass but it's increasingly unlikely, as the stone gets larger. Whenever possible, we like to give the stone every chance to pass by itself before resorting to surgery. Stones 7 mm or larger often require some type of surgery so it's important to know the exact size.

Can't You Dissolve The Stone With Medicine?

Unfortunately, most stones are made of a variety of calcium mineral combinations that cannot be dissolved with any known medication. About 10% of all stones are made up of uric acid. Only these uric acid stones can sometimes be dissolved with proper medication. But the majority of stones are made of calcium, which cannot be dissolved.

What About Using The "Stone Machine" To Break It Up?

The "Kidney Stone Machine" fragments stones by using shock waves produced at the bottom of a tank of water, which are focused at a predetermined spot. The patient is anesthetized and placed on a special frame, which is lowered into the tank. The patient and frame are then gently maneuvered in the tank until the stone is positioned precisely at the focal point of the shock waves. X-rays are used to pinpoint the location of the stone and to make certain it remains exactly at the correct spot. Each shock wave is generated separately and it literally vibrates the stone until it shatters and fragments without injury to the surrounding tissues. In order to use the machine, the stone needs to be large enough to see clearly under the X-rays we use for positioning. The stone must be in a location such as the kidney where the shock waves can reach it without any bone in the way.

What Causes Kidney Stones?

The answer to this question is that at some point there was simply not enough water in the urinary system to dissolve all the chemicals and minerals that were produced by the kidneys. It's like trying to dissolve a ten pound bag of sugar in a cup of coffee. There is just not enough fluid in just one cup to dissolve all that sugar. But if you throw that same ten pound bag of sugar in a swimming pool full of water, it will certainly dissolve. In order for a stone to form, there must not be enough water to dissolve all the chemicals and minerals the kidneys are trying to eliminate through the urine.

At the same time, many patients will also have a chemical or mineral imbalance in their systems. Some patients are just unable to produce urine with sufficient chemical inhibitors to prevent stones from forming. Other patients will absorb a higher percentage of minerals through the intestinal tract than the average person. These excess minerals will then be excreted by the kidneys and will tend to form new stones.

How Can I Avoid Getting More Kidney Stones?

While we have excellent methods of fragmenting stones with shock wave machines, lasers and lithotriptors, it is much more efficient and cost effective to eliminate the underlying metabolic causes of kidney stone formation whenever possible. This requires special chemical testing of the blood and urine to look for treatable abnormalities.

Therapy usually consists of various dietary adjustments or nutritional supplements and sometimes medication. The patient must be motivated to follow treatment suggestions for an indefinite period for this prevention program to be successful.

Without specific chemical testing, it's impossible to identify the particular cause for an individual stone. In general, we recommend increasing fluid intake throughout the day and dietary moderation of most food groups. In particular, patients should avoid excessive intake of meat, salt and calcium.

What About Just Limiting My Intake Of Calcium And Dairy Products?

Many kidney stone patients severely restrict their calcium intake without realizing that such a reduction in dietary calcium can actually increase their risk of calcium stone disease. Dietary calcium has an important role to play in binding other minerals within the intestinal tract. A significant reduction in calcium intake can cause an increase in absorption of some of these other minerals, which are normally bound or attached to the calcium. When no calcium is available for these minerals to bind to, they are left free to be absorbed by the body and eventually excreted in the urine where they can help form stones. The net result is an increase in your risk of forming more calcium stones if you restrict calcium intake too severely!

What Is Involved In Kidney Stone Prevention Testing?

Laboratory testing of the blood and urine is needed to identify the chemical risk factors in kidney stone formation. A 24-hour urine sample is collected along with a blood test. These samples are then tested extensively to uncover the predisposing chemical problems that lead to kidney stone formation. Any stone material that has been passed must be sent for chemical analysis. This will help in developing a treatment plan to prevent more kidney stones from forming. Insurance usually covers the cost of the stone prevention testing.

Where Can I Get Stone Prevention Testing And More Information About Kidney Stones?

An excellent quarterly newsletter specifically for kidney stone patients is available from the Kidney Stones Network at 1-800-254-3639. The Kidney Stones Handbook, a wonderful new book about kidney stones for patients and their families, is exclusively available from our office. For more information about the prevention and treatment of kidney stones or to obtain the stone prevention testing, please make an appointment with Dr. Stephen Leslie at (440) 985-9898. Our Amherst office is conveniently located at Route 2 and Leavitt Road.

Stephen W. Leslie, MD FACS, Urologist
Assistant Clinical Professor
Department of Urology
Medical College of Ohio

Medical Director and Founder
Lorain Kidney Stone Research Center
Lorain, Ohio