“…The effect on the renal parenchyma of the back pressure due to urinary obstruction is generally considered to be the main cause of the impairment (25). Variously, the following four factors have also been claimed to play a causative role: a) the obstructive pyelonephritis (7,19,20) frequently accompanying prostatic hyperplasia, b) the existence of reflexes in the urinary tract arresting kidney function (3), c) increased nitrogen resorption from the urinary tract (15), and d) coincidence with senile changes in the renal parenchyma (6).…”