Renal changes in vesicoureteral reflux--human reflux nephropathy.

25 nephrectomized kidneys of patients with vesicoureteral reflux (VUR) were examined during the period 1977 to 1985. In 13 cases, VUR was associated with other anomalies of the urinary tract. 14 patients were children aged 6 months to 15 years. The oldest of the 11 adult patients was 50 years old. Macroscopically the kidneys were mostly small with focal scarring of the renal parenchyma and dilatation of the corresponding calices. Histologically 5 children presented active pyelonephritis and 7 children atrophic chronic pyelonephritis. In adults there were 2 cases of atrophic chronic pyelonephritis and in the remaining 9 cases there was extensive segmental scarring characteristic of Ask-Upmark kidney. Two boys with VUR in association with a posterior urethral valve presented different changes, indicative of early intrauterine damage with arrest of differentiation. The morphologic changes in all other cases formed a broad essentially continuous succession of changes and should be seen as different developmental stages of chronic pyelonephritis of early childhood, Ask-Upmark kidney being the ultimate consequence. Despite a characteristic clinical picture and certain peculiar morphological features, there is no uniform and pathognomic picture of renal changes in reflux nephropathy. All our cases presented with urinary tract infection or a history of it and we regard them only as a specific pathogenetically determined form of child chronic pyelonephritis.