What is the most effective preventive strategy to prevent recurrence of renal lithiasis?

• A. Increase hydration
• B. Early treatment of urinary tract infection
• C. Limitation of calcium intake
• D. Use of probenecid

Answer: (A)

The main idea is that keeping the urine dilute by drinking more fluids is the most effective universal way to prevent stone recurrence. When urine volume is high, the concentration of stone-forming substances—such as calcium, oxalate, uric acid, and phosphate—drops, making it harder for crystals to form and grow. This approach works across most stone types, so it’s the foundational preventive measure; clinicians commonly aim for a urine output around 2 to 2.5 liters per day, adjusted for the individual.

Other strategies have roles in specific scenarios but aren’t as broadly protective. Treating urinary tract infections helps prevent stones that form because of infection (struvite stones) but doesn’t curb recurrence of non-infectious stones. Limiting calcium intake isn’t generally advised, because dietary calcium actually helps bind oxalate in the gut; too little calcium can increase urinary oxalate and stone risk. Probenecid affects uric acid handling but is not a standard preventive measure for kidney stones and can promote uric acid stone formation.