Studies on reflux nephropathy--clinical investigation of renal lesions

Renal biopsies were performed on 25 patients with reflux nephropathy to clarify the relationship between the pathological findings and clinical parameters. Biopsy specimens were obtained at anti-reflux operation by open renal biopsy. Glomerular lesions were classified as focal, diffuse, segmental and global sclerosis. Tubulo-interstitial changes were defined according to the principle advocated by Cotran and expressed as the percentage of the lesions. The clinical parameters consisted of the grades of VUR, the grades of renal scarring, renal function and the daily urinary protein excretion. A significant relationship was noted between the grades of VUR and those of renal scarring. The percentage of global sclerosis in the kidney revealed a close relationship with the grades of VUR and the percentage of tubulo-interstitial changes but not with the renal function or the daily urinary protein excretion. Focal segmental hyalinosis and/or sclerosis (FSHS) lesions were presented in 3 of 25 cases (12%). The pathological findings of the FSHS lesions had a close relationship with the renal function and the daily urinary protein excretion and the prognosis of the kidney. The other patients without FSHS lesions displayed an unchanged renal function. Based on these observations, it is clear that the prognosis of the patients with vesico-ureteral reflux could be predicted from the histopathological findings; the presence of FSHS lesions suggests a poor prognosis for the kidney. The degree of daily proteinuria represents a useful parameter for evaluating the progression of the reflux nephropathy.