Prone to Stones?

Tips for preventing painful kidney stones.

Painful kidney stones begin as crystals that form in the urine, a chemical concoction of water, calcium, citrate, oxalate, uric acid, proteins and other products of metabolism. More of one ingredient, or less of another, may tip the balance enough for the crystals to accumulate into stones.

For Howard Heller, M.D., an endocrinologist on the medical staff at Baylor University Medical Center at Dallas, preventing kidney stones is a matter of adjusting these ingredients to alter urine chemistry and interrupt the stone-formation process.

The key is to obtain a kidney stone analysis and a 24-hour urine collection from the patient, analyzing the volume, pH and composition of the urine. Once the makeup and underlying cause of the stone are determined, treatment approaches include dietary changes, increased fluid intake and medications.

"Most kidney stones are composed of calcium oxalate or calcium phosphate, and stone formers typically have a high level of calcium in their urine," Dr. Heller says. "But there are several different treatable risk factors for stones. There are three medications that have been clinically proven to prevent stone formation. Without treatment, more than 50 percent of patients will suffer another stone."

Dietary modifications, such as limiting oxalate-containing foods including spinach, chocolate and nuts, or cutting back on animal protein, also may alter urine composition enough to keep stones at bay.

While smaller stones can pass from the body unnoticed, anyone who has had a larger kidney stone will never forget the symptoms: severe pain on one side of the body, radiating toward the groin, sometimes with painful and burning urination. Fever or intractable pain or vomiting, Dr. Heller says, could be a sign that the stone has caused a serious infection or is obstructing the urinary tract—both of which require urgent evaluation.

Bottom line, drink plenty of water. Low urine volume is the major risk factor for kidney stones. "The greater your fluid intake, the less likely the salts in your urine will be able to crystallize and form stones," Dr. Heller says.

By Deborah Paddison

For a referral to an endocrinologist on the medical staff at Baylor Dallas, please call 1-800-4BAYLOR or use our on-line physician directory.