"Active" chronic pyelonephritis without evidence of bacterial infection.

Abstract The clinical records of 20 patients with histologically proved, nonobstructive "active chronic pyelonephritis" as their sole renal lesion were selected for study. Six had chronic or recurrent urinary-tract infection, and two gave a history of possible past infection. The remaining 12 had no clinical or bacteriologic evidence of either past or current infection. In four cases renal insufficiency progressed to a fatal termination, over a period during which repeated urine cultures remained negative. The possibility that prior asymptomatic bacterial infection was indirectly involved cannot be ruled out by these observations, but the data suggest that many examples of the lesion now called "active chronic pyelonephritis" may be of nonbacterial origin. These observations show that progression of this disease does not require the presence of demonstrable bacteria.