638 THE URINARY ORGANS. 



TUBERCULOUS NEPHRITIS. 



Miliary tubercles may be present in the kidney in general acute mili- 

 ary tuberculosis or in a localized tuberculous inflammation which is most 

 marked elsewhere. Eenal tuberculosis is, however, most often associated 

 with tuberculous processes in other parts of the geuito-uriuary tract. It 



FIG. 399. TUBERCULOUS NEPHRITIS. 



is not infrequently primary in the kidney and then is often unilateral. If 

 only one kidney be involved the other may become the seat of chronic 

 diffuse nephritis with waxy degeneration of the walls of the arteries. 

 Tuberculous inflammation may occur in a kidney already the seat of 

 chronic inflammatory changes. 



The process is apt to begin in the mucous membrane of the pelvis and 

 calyces, and extends from thence first to the pyramidal and afterward to 

 the cortical portion of the kidney. In the mucous membrane of the 

 pelvis and calyces there is a growth of new cellular tissue studded with 

 tubercle granula ; while the epithelial cells proliferate, become deformed, 

 and desquamate. This process is often soon followed by cheesy degen- 

 eration of the inflammatory products. Similar changes occur in the 

 kidney which may become extensively involved and largely destroyed. 

 The portions of the organ which do not share directly in the tuberculous 

 process often develop lesions of the interstitial type of chronic diffuse 

 nephritis or of suppuration. Thus the kidney may become hollowed out 

 into a series of ragged cavities with caseous and disintegrating walls 

 (Fig. 399). Sometimes the process comes to a standstill, and then the 

 caseous portions may be infiltrated with salts of lime. ' 



1 For a study of diffuse renal tuberculosis see Heyn, Virch. Arch., Bd.'clxv., p. 42. 



