Nephrolithiasis: acute management and prevention.

The primary care physician has a responsibility not only to recognize and treat acute stone passage but to ensure that the patient with recurrent stones has metabolic evaluation and appropriate preventive care. Renal colic is typically severe, radiates to the groin, is associated with hematuria, and may cause ileus. About 90% of stones that cause renal colic pass spontaneously. The patient with acute renal colic should be treated with fluids and analgesics and should strain the urine to recover stone for analysis. Highgrade obstruction or failure of oral analgesics to relieve pain may require hospitalization; a urinary tract infection in the setting of an obstruction is a urologic emergency requiring immediate drainage, usually with a ureteral stent. Several approaches are available when stones do not pass spontaneously, including extracorporeal shock wave lithotripsy, percutaneous lithotripsy, and ureteroscopic laser lithotripsy. Calcium stone disease has a lifetime prevalence of 10% in men and causes significant morbidity. Renal failure is unusual. Stone types include calcium oxalate, uric acid, struvite, and cystine. Stone analysis is particularly important when a noncalcareous constituent is identified. The majority of patients with nephrolithiasis will have recurrence, so prevention is a high priority. High fluid intake is a mainstay of prevention. Metabolic evaluation will indicate other appropriate preventive measures, which may include dietary salt and protein restriction, and use of thiazide diuretics, neutral phosphate, potassium citrate, allopurinol, and magnesium salts. Dietary calcium restriction may worsen oxaluria and negative calcium balance (osteoporosis).