THE URINARY ORGANS. 



627 



FIG. 383. ACUTE DIFFUSE NEPHRITIS. 



Showing pus cells and grandular exudate in the tu- 

 bules, with flattening of the epithelium ; also moderate 



of the kidneys, such as may occur independently or in connection with 

 acute infective processes elsewhere, there is an involvement of all the 

 structural units of the organ, the 

 glomeruli, the tubular epithelium, 

 and the interstitial tissue. Such 

 a process involving the various 

 kinds of tissue is called diffuse, ' 

 and the process is therefore desig- 

 nated Acute Diffuse Nephritis. 



While both kidneys are in- 

 volved in acute diffuse nephritis, 

 the lesions in each are by no 

 means uniform either in extent or 

 advancement and are often patchy 

 or irregular in distribution. 



Variations in Type in Acute 



Diffuse Nephritis. There are many oedema of the interstitial tissue-exudative type. 



variations in the type of the le- 

 sions in acute diffuse nephritis, some of which seem to be directly de- 

 pendent upon the character of the excitant, while in others the varia- 

 tions cannot as yet be associated with known determining conditions. 



If one guard himself against the notion of distinct species in the le- 

 sions it is convenient to recognize certain structural variants or types. 

 Thus the changes in the glomerular capillaries and epithelium may, 

 as above indicated, be prominent glomerular type (so-called glomerulo- 

 neiyhritis*) (Figs. 386 and 387) ; the degenerative process in the tubular 

 epithelium may be extreme parenchymatous or degenerative type ; there 

 may with other lesions be considerable haemorrhage into the glomeruli 

 tubules and interstitial tissue hcemorrlmgic type. With or without marked 

 structural involvement of the parenchyma and interstitial tissue there 

 may be an exudative inflammation in which serum and leucocytes (Fig. 

 388) and more or less red blood cells may gather in the glomeruli or tu- 

 bules and with various forms of casts pass off in the urine. This, which 

 is common, has been called by Delafield the exudative type of acute diffuse 

 nephritis. Finally, with any one or more of the above types of lesion 

 there may be early and significant involvement of interstitial tissue of 

 the kidney, so that new and often very cellular tissue, either in small 

 patches or through a large portion of the organs, may lead to tubular 

 atrophy and to serious and permanent structural alterations. This, which 

 has been called by Delafield the productive type, by others tbe interstitial 

 type of acute diffuse nephritis (Figs. 387 and 389), is most frequent as a 

 complication of scarlatina ; it may follow diphtheria, or puerperal infec- 

 tions, and may occur as an apparently independent process.* 



1 It should be understood that the word " diffuse " is not used in the sense of wide- 

 spread or uniform, but as indicating involvement of the various structural units of the 

 organ. 



'-Consult for an interesting study of "acute interstitial nephritis," Councilman, 

 Jour. Exp. Med., vol. iii., p. 393, 1898. Councilman regards the new cells in the inter- 

 stitial tissue as largely " plasma cells " derived from lymphoid cells of the blood. 



