Historical Review of Concept of Pyelonephritis

Abstract

The place of pyelonephritis in the spectrum of renal diseases has substantially changed over the years. Four main steps may be identified. At the beginning of the century, the concept of pyelonephritis was virtually unknown: in fact, no reference to this disease are found in the classic work of Volhard and Fahr on Bright’s disease, thought previous probable examples of chronic forms were mentioned on earlier studies by Wagner (1882). The second step was represented by the histologic recognition and overdiagnosis:in fact chronic interstitial inflammation associated with tubular atrophy was always attributed to chronic pyelonephritis, thus leading pathologists to overdiagnose the disease. The third step was represented by the clinical recognition and overdiagnosis. In fact, urinary infections were recognized to be common, and it was accepted that they could often spread to the kidneys evolving to acute and chronic damage, so that chronic pyelonephritis was considered to be the commonest renal disease leading to chronic renal failure. The fourth step is the current one, due to the application of stricter diagnostic criteria arising basically from the knowledge that histologic features are non specific and may result from interstitial disease with many other non bacterial pathogenetic mechanisms. Furthermore, the relationships between urinary infection and parenchimal and pyelocaliceal involvement are now better understood, the role of predisposing factors is underscored,and the possibility that interstitial lesions may evolve to end stage disease even in the absence of bacterial infection is now well accepted.