Published: June 18, 2007 11:05 pm         

Avoiding the pain of kidney stones

Do you sweat a lot while working or exercising? Do you eat a lot of meat, cheese and animal protein? Do you drink less than two liters of water a day? Do you often pig out on rhubarb, grapes, spinach or strawberries?

If you answered yes to one of the above questions, you may have an increased risk of having a kidney stone.

A kidney stone is a hard mass that crystallizes from various substances in urine and builds up on the inner surfaces of the kidneys.

Individuals who get dehydrated often are at risk of a kidney stone. That includes people who live in hot climates, athletes who sweat a lot and even truck drivers who have limited opportunities for toilet stops. Meat and other animal protein tends to lower the pH level of urine, promoting the development of stones. Vegetarians have a lower risk, but rhubarb, grapes, spinach, tea, chocolate and strawberries are high in oxalate, a major component of many stones.

A stone may be as small as a grain of sand or as large as a golf ball; it may be smooth or jagged. And while small ones may come out in the urine without difficulty, larger ones are likely to cause excruciating pain.

Stones measuring six millimeters and greater often require intervention. As recently as 20 years ago, removing a kidney stone required surgery. Today several less invasive procedures are available.

Extracorporeal shockwave lithotripsy (ESWL) involves the use of sound waves to break a stone into sand-like particles that can be easily passed through urination. ESWL can be performed on an outpatient basis, and the patient is able to resume normal activities within a few days.

Uteroscopy involves inserting a small fiberoptic instrument through the urethra and bladder into the ureter, locating the stone and either removing it or shattering it with an instrument that produces a shock wave.

Precutaneous nephrolithotomy is more commonly used when the stone is large or in a position that does not allow effective use of ESWL. A small incision into the back is necessary, and a scope in inserted directly into the kidney to locate and remove the stone.

Once a person has had a kidney stone, the reoccurrence rate is 15 percent at one year and 50 percent by the end of five years. Preventive treatment is crucial.

A simple but important first step is to increase fluid intake — drinking enough to produce at least two quarts of urine a day. Water is best, but fluids containing citrate (such as lemonade or orange juice) are also beneficial.

For calcium stones, it was once believed calcium restriction could lower the risk. Studies have shown persons with the highest calcium intake are least likely to develop kidney stones. A normal amount of calcium in the diet is now recommended.

Cutting back on animal protein and oxalate-rich foods is advised. And diuretics such as hydrochlorothiazide may be prescribed to increase urinary volume and reduce the concentration of calcium in the urine. These medications work best when sodium intake is low. Other medications often prescribed include allopurinol and potassium citrate.

About 1.2 million Americans suffer from kidney stones each year, and the pain can be excruciating. With a few easy preventive measures, you may be able to avoid the experience.



Rupp is information and assistance case manager with the Northern Oklahoma Development Authority Area Agency on Aging.