Obstructive nephropathy: pathophysiology, diagnosis, and collaborative management.

Patrick A. Palmieri, MSN, MBA, ACNP, RN, is Avera Health Administrative Fellow, Avera Sacred Heart Hospital, Yankton, SD, where he is responsible for clinical program development. At the time this article was written, he was a student in the Graduate Program at Vanderbilt University School of Nursing, Nashville, TN. Renal failure is often identified with a specific precipitating event, such as obstructive uropathy, which can lead to obstructive nephropathy. Obstructive uropathy is structural impedance to the flow of urine anywhere along the urinary tract (Walsh, Re t n i k , Vaughan, & Wein, 1998 ) . Unidentified and untreated obstructive uropathy can lead to hydronephrosis, which is dilation of the renal pelvis and calyces resulting from obstruction to flow of urine. The damage caused by these conditions often leads to obstructive nephropathy, that is, damage to the renal p a r e n chyma. All three of the terms are interrelated and collectively contribute to a decrease in renal function (Klahr, 1998a). The onset of obstructive nephropathy can be acute or gradual, depending on the etiology. Unlike many other renal diseases, obstructive nephropathy often is reversible with early diagnosis and treatment (Chevalier & Klahr, 1998 ) . Obstructions of the urinary tract can occur in any part of the system, including the urethra, bladder, ureters, or renal pelvis (Yarger, 1991 ) . Obstructive uropathy associated with congenital anomalies of the urinary tract accounts for 30 – 50% of all end stage renal disease (ESRD) cases in children (Huang, Palmer, Ho m , Valderrama, & Tr a chtman, 20 0 0 ) . The condition incidence declines in adults until the age of 60, when the incidence rises, particularly in men because of prostate disorders (most notably benign prostatic hypertrophy [ BPH]) (Klahr, 1998 a ) . In young adults, obstructive uropathy has a greater incidence in women than in men because of processes that affect the female reproductive tract, such as malignant pelvic neoplasm or pregnancy, which displace tissue around segments of the urinary tract (Yarger, 1991). In more than 60% of pregnant women during the third trimester, dilation of the collecting system is evident (Murano, 1993). Overall, elderly men are at greatest risk of developing renal failure from obstructive nephropathy. The prevalence of BPH at autopsy is 50% by age 60 and 90% by age 85 . Urinary obstruction caused by prostatic disease is responsible for 5% of new ESRD cases in the population over the age of 65 years (United States Renal Data System [USRDS ] , 1996). Given the frequency of BPH in elderly men and the increasing number of elderly men in the United States, the potential for increasing numbers of patients with obstructive nephropathy is significant. Among patients with renal and urologic disorders, obstructive uropathy ranked fourth for men and sixth for women as the diagnosis at discharge (Klahr, 1998a). Excluding congenital obstructive uropathy, a total of 4 , 869 patients with the diagnosis of obstructive nephropathy began ESRD treatment in the United States from 1989 to 1993. Of the 4,869 patients, 74% were male, 81% were White, and 16% were AfricanAmerican. The majority of the patients (57%) were over 64 years of age, 36% were 20 to 64 years of age,