Doctora

M e d i c a l an d M e d i c a l / U ro l o g i c A p p ro a c h e s i n A c u t e an d C h ro n i c U ro l o g i c S t o n e D i s e a s e
Timothy Y. Tseng,
KEYWORDS  Nephrolithiasis  Urolithiasis  Kidney stones  Management  Prevention
MD
a

, Marshall L. Stoller,

MD

b,

*

Urinary stone disease is a condition with far-reaching implications. Patients with their initialpresentation of acute renal colic generally enter the health care system through 2 routes. Severe cases are seen in the emergency room, whereas more tolerable cases may be seen by primary care physicians. Patients with urinary stone disease are then managed in the long-term by a urologist. This article reviews the epidemiology, pathogenesis, presentation, and short- and long-term management of acuteand chronic urinary stone disease.

EPIDEMIOLOGY

In the United States, the 1988 to 1994 National Health and Nutrition Examination Survey (NHANES III) prospective cohort study found the lifetime prevalence of urinary stone disease to be 5.2%.1 Stone disease seems to be on the rise, because the 1976 to 1980 NHANES II study recorded a lifetime prevalence of only 3.2%. In NHANES III, lifetimeprevalence of stone disease was higher in men at 6.3% compared with 4.1% in women. The risk of stone disease generally seemed to increase as one aged, with the highest prevalence of stone disease in men occurring in the 70- to 74-year-old age group at 13.3%. Women experienced a peak prevalence in their sixth decade of 7.0%. In general, non-Hispanic Caucasian patients had the highest risk of urinarystone disease with a prevalence of 5.9%. Hispanic and African American patients had lower risks of stone disease with prevalences of 2.6% and 1.7%, respectively. Geography

Department of Urology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA b Department of Urology, University of California San Francisco, Box 0738, 400 Parnassus Avenue, UC Clinics A-638, SanFrancisco, CA 94143-0738, USA * Corresponding author. E-mail address: mstoller@urology.ucsf.edu Med Clin N Am 95 (2011) 169–177 doi:10.1016/j.mcna.2010.08.034 0025-7125/11/$ – see front matter Ó 2011 Published by Elsevier Inc. medical.theclinics.com

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also seemed to play a role in the risk of stone disease. The US South had the highest age-adjusted lifetime prevalence ofstone disease at 6.6%, whereas the West had the lowest prevalence at 3.3%. In the Midwest, the prevalence was 4.6% and in the Northeast, 5.1%. Regarding costs, as urinary stone disease is increasingly treated on an outpatient basis, the number of inpatient discharges for a diagnosis of urolithiasis has been declining gradually. Nevertheless, in 2007, the Nationwide Inpatient Sample recorded155,860 urinary stone inpatient discharges. At an estimated true cost of $6128 per inpatient discharge, the total cost of these hospitalizations was $955,192,450.2 The actual cost for treatment of urinary stone disease would probably be several orders of magnitude greater if outpatient procedures were included. Proper acute and long-term management of such patients is therefore essential.
PATHOGENESISThe vast majority of patients with urolithiasis have stones composed of calcium oxalate (65%–70%) or calcium phosphate (16%–20%). Approximately 8% of patients have stones composed of uric acid. An additional 2% of patients have cystine stones.3,4 Stone formation historically has been viewed as a disorder of mineral metabolism. Conditions leading to the supersaturation of urine with variousminerals result in their precipitation out of the urine. Predisposing conditions can include low urine volumes, increased urinary mineral excretion, and abnormal urine pH leading to altered solubility.5,6 Excluding low urine volumes, the most common abnormality found in patients with urolithiasis is hypercalciuria, defined as a urinary calcium excretion of greater than 200 to 250 mg/d or greater...