Creatinine clearance and renal interstitium in diffuse endocapillary proliferative glomerulonephritis.

ABSTRACT

Morphometric investigations of the renal cortex on biopsies obtained from patients with diffuse proliferative endocapillary glomerulonephritis (EPGN) were compared to biopsies without pathological changes, both groups having a normal serum creatinine concentration at the time of biopsy. Our findings are as follows In both groups a statistically significant correlation exists between the decrease of the endogenous creatinine clearance and the broadening of the interstitium. The mean endogenous creatinine clearance value in EPGN is 107.6 +/- 40.6 ml/min/1.73 qm, the mean endogenous creatinine clearance in normal kidneys is 108.2 +/- 28.5 ml/min/1.73 qm; the mean interstitial volume in EPGN is 14.5 +/- 2.9 vol.%, that in normal kidneys 9.5 +/- 2.9 vol.%, the difference is statistically significant. Comparing the run of the two curves (relationship between endogenous creatinine clearance and interstitial volume) of the investigated groups, one finds that they run a nearly parallel course, the curve of the EPGN being shifted statistically significant to the right. The mean values of number, single- and total area of the peri- and intertubular capillaries are identical in the cases of EPGN and in those biopsies without pathological findings. Furthermore no correlations could be established between the above mentioned measuring values and the endogenous creatinine clearance in the both investigated groups. Consequently in these cases with normal serum creatinine concentration the reduction of the glomerular filtration rate (gfr) accompanied by interstitial broadening cannot be explained by an impairment of the postglomerular blood flow. Perhaps a tubular functional disturbance, the cause or the consequence of the interstitial broadening impairs glomerular function by the tubular-glomerular feedback-mechanism and/or by an elevation of the intratubular hydrostatic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)