Q: Why is summer a high-risk time for kidney stones?

A: Hotter temperatures often bring an increased risk of kidney stones, which affect about 3.8 million people each year in the U.S. The most common reason for kidney stones is dehydration. As we sweat more in the summer, our bodies can become dehydrated. Without enough water, dietary minerals such as calcium become more concentrated in the body's fluids, which raises the risk that the minerals will become stones. Many people don't drink enough fluids to compensate for the warmer temperatures, or they drink fluids such as beer, iced tea, colas, and caffeinated beverages that work against the body's need for fluids.

Factors that can raise your risk of kidney stones include recurrent urinary tract infections and a family history. For those at high risk of kidney stones, it is recommended that you drink about eight 12-ounce glasses of non-caffeinated liquid per day, especially water. Citrate is an inhibitor of urinary crystal formation, so orange juice and lemonade can help protect against kidney stones.

A diet high in refined sugars, salt, and animal protein may be a factor in kidney stone formation. Animal protein acidifies the urine and promotes crystal formation. Excess sodium causes more calcium to enter the urine, raising the risk for stone formation. High-fructose corn syrup also increases urinary calcium excretion.

The first symptom of a kidney stone is usually extreme pain in the back and side in the area of the kidney or in the lower abdomen. This occurs when a stone acutely blocks the flow of urine. Although some kidney stones pass on their own, seek immediate medical attention if you experience pain so severe that you can't sit still or find a comfortable position, suffer pain with nausea and vomiting or fever and chills, see blood in your urine, or have difficulty passing urine.