Yes, bariatric weight loss surgery can reward patients with a better quality of life, and improved health, in general. However, no procedure is completely without drawbacks, and as such, bariatric patients should be aware of the risk for side effects. And one surprisingly common side effect that bariatric patients must be aware of is that of developing kidney stones.

According to Dr. Bill Harmon, an urologist at Urology San Antonio, patients who have undergone bariatric procedures have increased concentrations of a compound known as calcium oxalate in their urine. Not only can the tiniest accumulations block urinary flow, but if left untreated, they can grow into larger stones. When stones develop, urologists must break them up, so that they can be safely and easily passed out of the body. These procedures can be performed with scopes, or through the procedure known as “lithotripsy,” in which the stone is broken up (with little collateral damage) with an externally-applied, focused, high-intensity acoustic pulse.

Kidney stones are particularly likely to develop after bypass surgery. As bypass patients have smaller stomach paunches, they may not be drinking enough water to prevent stone development. Harmon states: “Most of the bariatric surgeons are aware of this risk. And they have all of their patients drink plenty of fluids. Usually it’s three to four quarts a day if they can take it in.”

The good news is that kidney stones are NOT life-threatening. In addition, bariatric weight loss surgery patients can make dietary changes and take supplements that may effectively reduce and avoid kidney stone development. But the bottom line is, it’s important for patients to carefully follow their doctor’s instructions, especially after the procedure.