Kidney Stones

If you've ever passed a kidney stone, you're not likely to forget the experience — it can be excruciatingly painful. Kidney stones (renal lithiasis) are an ancient affliction dating back to the age of the Egyptian pyramids, yet they are still a common disorder today.

What is it?

The incidence of kidney stones has been increasing in recent decades. Although the reasons for this are still unclear, many experts believe that diet choices and lack of fluids are important factors that have contributed to this increase.

Not all kidney stones cause symptoms. They're often discovered when you have X-rays for an unrelated condition or when you seek medical care for other problems, such as blood in your urine or recurring urinary tract infections. The pain becomes agonizing only when a kidney stone breaks loose and begins to work its way down from your kidneys to your bladder through the connecting tube (ureter).

Kidney stones usually form when your urine becomes too concentrated. This causes minerals and other substances in urine to form crystals on the inner surfaces of your kidneys. Over time, these crystals may combine to form a small, hard mass, or stone.

Most small kidney stones pass into your bladder without causing any permanent damage. Still, it's important to determine the underlying cause so that you don't form more stones in the future. In many cases, you can prevent kidney stones simply by drinking more water and making a few dietary changes.

What causes it?

Your kidneys are two bean-shaped organs, each about the size of your fist. They're located in back of your abdomen on each side of your spine, and their main function is to remove excess fluid, unneeded electrolytes and waste from your blood in the form of urine. The ureters carry urine from your kidneys to your bladder, where it's stored until you eliminate it from your body.

The crystals that lead to kidney stones are likely to form when your urine contains a high concentration of certain substances — especially calcium, oxalate, uric acid and rarely, cystine — or low levels of substances that help prevent crystal formation, such as citrate and magnesium. Crystals also may form if your urine becomes too concentrated or is too acidic or too alkaline.

A number of factors can cause changes in your urine, including the effects of heredity, diet, drugs, climate, lifestyle factors and certain medical conditions.

What are the symptoms?

You're not likely to have signs and symptoms unless a kidney stone is large, causes a blockage, is associated with an infection or is being passed. Then the most common symptom is an intense, colicky pain that may fluctuate in intensity over periods of five to 15 minutes. The pain usually starts in your back or your side just under or below the edge of your ribs. As the stone moves down the ureter toward your bladder, the pain may radiate to your lower abdomen, groin and genital structures on that side. If the stone stops moving, the pain may stop too. Other signs and symptoms may include:

• Bloody, cloudy or foul-smelling urine
• Nausea and vomiting
• Persistent urge to urinate
• Fever and chills if an infection is present.

Are there any natural therapies?

Treatment for kidney stones varies, depending on the type of stone and the cause. You may be able to move a stone through your urinary tract simply by drinking plenty of water — as much as 2 to 3 quarts a day — and by staying physically active.

Stones that can't be treated with more-conservative measures — either because they're too large to pass on their own or because they cause bleeding, kidney damage or ongoing urinary tract infection — may need professional treatment.

What else can I do?

In many cases, you can prevent kidney stones by making a few lifestyle changes. If these measures aren't effective and blood and urine tests reveal a correctable chemical imbalance or that the stones you have are getting bigger, your doctor may prescribe certain medications.

For people with a history of kidney stones, doctors usually recommend passing at least 2.5 quarts of urine a day. To do this, you'll need to drink about 3.5 quarts (14 cups) of fluids every day — and even more if you live in a hot, dry climate. Although most liquids count, water is best.

In addition, if you tend to form calcium stones — a combination of calcium and oxalate — your doctor may recommend restricting foods rich in oxalates. These include rhubarb, star fruit, beets, beet greens, collards, okra, refried beans, spinach, Swiss chard, sweet potatoes, sesame seeds, almonds and soy products. What's more, studies show that an overall diet low in salt and very low in animal protein can greatly reduce your chance of developing kidney stones.

Did you know?

These factors may increase your risk of developing kidney stones:
Lack of fluids.
Family or personal history.
Age, sex and race.
Certain diseases.
Certain medications.
Diet.
Limited activity.