Acute renal failure due to urinary tract obstruction.

Urinary tract obstruction is a frequent cause of acute renal failure that is potentially life threatening but reversible, if it is promptly recognized and corrected. The level of urinary tract obstruction is variable, dependent on the underlying disease, and may range from the loop of Henle to the urethral meatus. Clinical manifestations are most commonly due to renal failure, but the history and physical examination can aid in determining the localization and cause of the obstruction. Laboratory findings may suggest urinary tract obstruction as the etiology for acute renal failure. Radiologic procedures, most prominently ultrasonography, can establish the diagnosis. Treatment is variable, but patient management may need to be altered during the postobstructive phase of urinary tract obstruction owing to physiologic response to reestablishment of urine flow.