Atubular glomeruli in chronic renal disease.

The pathological changes in chronic renal failure are heterogeneous and may depend on the primary disease process. Renal function is better correlated with tubular and interstitial changes than with glomerular changes detectable in simple two-dimensional sections. Atubular glomeruli have been demonstrated in many tubulointerstitial disorders. They constitute a significant portion of the glomerular population in some chronic renal diseases. The atubular glomeruli are generally small, but they have open capillaries and minor ultrastructural changes. The number of capillaries is decreased. Glomeruli connected to normal proximal tubules have volumes at the normal level or above. They have not been shown to be eliminated. The presence of atubular glomeruli may explain the correlation between the volume of proximal tubules and the volume of interstitium, on the one hand, and altered renal function on the other. The presence of atubular glomeruli could explain the irreversibility of chronic renal diseases. It is likely that interstitial fibrosis and tubular atrophy in themselves contribute to the decrease in renal function of both glomerular and nonglomerular renal diseases. In glomerular diseases, the glomerular lesion and hyperfiltration may play the major part in the pathogenesis of the deterioration of renal function. The available evidence points toward glomerulo-tubular disconnection as an important and common cause of progression and irreversibility of chronic renal diseases. It provides a simple explanation for the common observation of severely reduced kidney function and mostly normal-looking glomeruli--at least in two dimensions.