An Atypical Response of the Kidney to a Period of Ureteric Obstruction

Abstract Twenty cases in which a kidney showed an atypical response to a period of obstruction are presented. The kidney was small, with a smooth outline, a reduced rate of urine production; and a reduced contrast medium concentration in the urine. The papillae, however, were normal or near normal in contrast to the expected atrophy of papillae in the typical postobstructive state. This response appears to be due to a combination of obstruction and ischemia. It is suggested that previous obstruction be considered in the differential diagnosis of any “miniature” kidney.