Relationship between glomerular lesions, serum creatinine and interstitial volume in membrano-proliferative glomerulonephritis

Morphometric investigations in 33 patients suffering from membranoproliferative glomerulonephritis at different grades of glomerular involvement showed that there is no certain relationship between the severity of glomerular lesions and the serum creatinine level. On the other hand there is a significant positive correlation between the relative interstitial volume and the level of serum creatinine. The best congruence (r=+0,87, p less than 0.0001) showed an exponential function y=0.563-e0.049x. We therefore conclude that in membranoproliferative glomerulonephritis which is generally considered to be a glomerular disease, interstitial changes have to be taken into account as a cause of renal insufficiency. Glomerular lesions alone cannot explain the functional impairment. The pathophysiologic factors concerning increased interstitial volume as a cause of renal insufficiency - probably immunologic in origin - are yet to be completely clarified.