By Scott Angell

Approximately 10 percent of Americans will get kidney stones at some point in their lives. This is one of the most common - and unfortunately one of the most painful - urinary tract disorders.

Kidney stones are crystallized mineral deposits that form inside the kidneys. While urine naturally contains chemicals that prevent these masses from forming, this process can fail - leading to kidney stones.

Kidney stones are most common in white Americans, and men tend to get them more often than women. Individuals who have had more than one kidney stone are likely to develop them again in the future.

There are several causes, including diet, genetics and a family history of kidney stones. Other causes include urinary tract infections, kidney disorders and metabolic disorders such as hyperparathyroidism, a disorder of the parathyroid glands.

Symptoms

In some cases, kidney stones go unnoticed until they show up on X-rays during a patient’s general health examination. In many cases, however, an individual experiences the following symptoms:

Sharp, sudden, cramping pain in the lower abdomen, sometimes spreading to the groin

Nausea and vomiting

Blood in the urine

The urge to urinate more often, or a burning sensation while urinating

Fever and chills (This may indicate an infection requiring immediate medical attention.)

Treatment

If kidney stones remain very small, they can pass through the urinary tract unnoticed. However, sometimes they get large enough to create problems. When that happens, there are several treatment options available.

A shock wave treatment called extracorporeal shock wave lithotripsy breaks the kidney stones into tiny pieces that can then pass through the urinary tract.

Kidney stones too large to be treated with this can be broken down and removed using a surgical procedure called percutaneous nephrolithotomy, which involves the use of special scopes passed into the kidney through a small incision.

Open surgery is rarely needed these days.

Prevention

The next step after treatment is prevention. A doctor may want to do an X-ray every six months for two years to determine whether a patient is forming more kidney stones.

While preventive techniques vary based on the cause of the problem, following are some general recommendations to prevent the formation of kidney stones:

Drink more water - approximately 1.5 liters per day (approximately four 12-ounce glasses).

Avoid beverages with caffeine, since they tend to cause dehydration.

Cut back on oxolate, a mineral found in chocolate (including chocolate beverages and cocoa), green leafy vegetables (especially spinach), coffee, tea and rhubarb.

Focus on a low-sodium diet.

Maintain a low-protein diet, eating meat only two times per week and avoiding dried beans, lentils and peas, as well as liver, sweetbreads and kidney.

Avoid cranberries, plums, gooseberries, raspberries and asparagus.

In the past, doctors advised people with kidney stones derived from excess calcium to restrict their intake of dairy products and other foods containing calcium. However, recent studies indicate that eating natural foods high in calcium is not a problem. The concentrated levels of calcium found in pill form, on the other hand, can be problematic.

Kidney stones are a common problem, but fortunately there are many treatments and preventive measures that are highly effective.

The Palo Alto Medical Foundation and column editor Arian Dasmalchi provide this monthly column.