Preventing kidney stones

One of the first phone calls I received when I began working in urology was from a patient that told me he had a kidney stone.  When I naively asked him how he knew this he paused and said “You’re new there aren’t you?”  I quickly learned that once someone has a stone they can generally recognize the pain as soon as it begins. It is a pain that is unpredictable and at times debilitating.  This is why preventing kidney stones is important.

There are multiple risks factors for stone formation. Some of them are more obvious than others such as dehydration, high oxalate, sodium or calcium diet habits, or a family history. Others risk factors may not be as well-known including obesity, certain medications such as Topamax and high dose calcium containing supplements, gastric by-pass surgery, some GI disorders, and certain metabolic issues.  In the South we have a greater risk of stone formation because of sun exposure and inadequate fluid intake especially in the summer. Recent studies have shown that stone formation is on the rise among populations that used to be at a lower risk including women.  This is probably due to an increase in obesity and poor fast food dietary habits.

It is important to stress to patients what they can do to prevent stone formation.  In the past we told patients to drink at least 2 liters of water a day. However: the current belief is that people at risk for stones should drink enough fluids to have at least 2 liters of urine output each day which would mean upwards of 3 liters of fluid intake daily.  Losing weight if the patient is overweight, adding lemon juice to fluids and food to increase citric acid intake, limiting salt intake, and limiting high oxalate foods are important behavioral steps to decreasing stone formation.

Individuals that repeatedly form stones or begin forming stones as children or adolescents need a full metabolic workup including stone analysis if possible, blood chemistry and 24 hour urine evaluations. In some instances medications such as thiazide diuretics, potassium citrate, or allopurinol may be recommended depending on the test results.