1016 Bacterial Pyelonephritis. 



membrane of the renal pelvis in general become involved in 

 the diphtheritic and suppurating inflammatory process. Of 

 the peripheral urinary passages the bladder is most endangered 

 (and also the urachus if this is not yet obliterated) because the 

 urine remains there for a longer time. Accordingly a very severe 

 inflammation sometimes develops in the bladder. The affection 

 of the descending urinary passages, not excepting the ureters, 

 is greatly favored by the urinary stasis which necessarily 

 occurs, at least at times during the disease, and also by the 

 constant irritation bj^ the disintegration products of the urine. 

 Under these conditions the germs are packed into the collecting 

 tul)ules and, after the destruction of the pelvic mucous mem- 

 l)rane, the inflammatory process continues directly into the 

 renal tissue. In this manner an ascending inflammation of 

 the kidneys is added to the original process. ^ 



In the urogenic origin of the disease, which is undoubtedly 

 infrequent, the inflannnation of the kidney commences with 

 the process that was just described, after the inflammation has 

 existed for some time in the urinary passages. 



It appears from what has been said that no sharp distinptions can be drawn 

 between embolic purulent nephritis and bacterial pyelonephritis. 



Anatomical Changes. In well developed cases both kidneys 

 or only one are enlarged more or less, 1-4 kg. in weight (in a 

 case of Cadeac's the kidney weighed 6.5 kg.). The renal capsule 

 is thickened, adherent to the cortex in many places and in varia- 

 ble extension, the surface of the kidney is multi-colored ; on 

 a red-brown ground yellowish-gray islands are prominent, and 

 corresponding with them striae or wider wedge-shaped bands 

 of similar color are visible on the cut surface. Within these 

 islands and within the brown portions of the kidneys there 

 appear yellowish-gray, turbid small foci which are suppurating 

 and soft or friable and cheesy, each one being surrounded by 

 hemorrhagic spots. Hemorrhagic infarcts are rare. Later the 

 consistency of the kidney increases, ])ut in the initial stage 

 the tissue shows more or less serous infiltration. 



The dilated pelvis of the kidney contains a dirty-gray, 

 grayish-yellow, yellowish-brown or brownish fluid which may 

 be l)loody discolored, cloudy, flocculent and peculiarly milky 

 and which contains pus, tissue shreds, blood clots and granular 

 calcareous material. The mucous membrane is much swollen 

 or tliickened, in recent cases studded with hemorrhagic spots; 

 in places it shows ulcerous destruction or dirty-gray deposits. 

 The renal papillae are covered with a viscid purulent substance, 

 they are reddened and terminate in dirty discolored tissue 

 slireds so that they have an eroded appearance. Sometimes the 

 places of the renal papillae are occupied by hollow spaces 

 filled with purulent masses (Pyelonephritis cavernosa) or if 

 the process progressed by multiple lobar extension, the entire 



