Risk for renal failure in nephrolithiasis.

Evaluation of the risk for developing renal insufficiency is generally not considered during the clinical metabolic workup of the stone-forming patient. This review approaches the problem of the severity of nephrolithiasis by addressing the renal risk. Although renal stones are an infrequent cause of renal failure, some lithiasic forms present a greater risk, such as in hereditary stone diseases (eg, cystinuria, primary hyperoxaluria, Dent's disease), primary struvite stones, and infection-related urolithiasis associated with anatomic and functional urinary tract anomalies and spinal cord injury. Recurrent bouts of obstruction and/or crystal-specific biological effects on tubular epithelial cells and interstitial renal cells may activate the fibrogenic cascade responsible for the loss of renal parenchyma. In clinical terms, frequent stone relapses, episodes of urinary tract infection and obstruction, number of urological interventions, and size of the gravel are all significantly associated with the risk for renal failure. Percutaneous and extracorporeal urological methods for the treatment of renal stones may also lead to some chronic deterioration of renal function, particularly in recurrent stone formers treated with multiple therapeutic sessions. Although still speculative, concerns exist about the effect of extracorporeal shock wave lithotripsy on small or pathological kidneys. Without doubt, the medical prevention of stones would be more sensible.