1008 Purulent Nephritis. 



Anatomical Changes. If the iuflanimation is metastatic, 

 both kidneys are usually involved, in other forms usually only 

 one and this may be affected only partially. The embolic 

 purulent foci are found principally in the cortex. 



According to Kitt purulent nephritis occurs in the following forms : 



Nephritis purulenta (punctata, disseminata). The substance of 

 the kidneys which are more or less enlarged contains numerous small 

 Avhitish or yellowish dots and stripes which are surrounded by a 

 narrow, dark red areola (hyperemia and hemorrhage) and from which 

 thickish purulent masses may be lifted with the knife. The tissue 

 around these places is changed in variable extension similarly as in 

 the acute diffuse inflammation. In hogs, less often in calves and cattle, 

 tough white bands are seen between the purulent foci. 



On microscopical examination conglomerations of pus cells are found inside 

 of the small foci, and cellular infiltration containing pyogenic bacteria is noted in 

 the surrounding tissue. The epithelial cells show fatty degeneration and are disin- 

 tegrated, the glomeruli are sometimes surrounded by pus, while the convoluted capil- 

 laries contain numerous leucocytes; in the urinary tubules casts are sometimes found 

 which carry leucocytes and red blood cells. 



The hematogenic purulent nephritis of hogs which has been 

 studied more exactly by Degen belongs to this form. It commences 

 mostly in the cortical substance with the formation of dark red foci, 

 of from hemp seed to pea size. In these foci a central yellowish-white 

 spot soon becomes visible as large as grits or up to birdshot in size. 

 The foci eventually become tougher, their areola paler, the yellowish 

 color of the center passes into a grayish- white and gray- white ; sharply 

 confined and slightly depressed cicatrices appear on the surface of the 

 kidneys, continuing into the substance of the kidney in the form of 

 wedges or strips. Abscesses are hardly ever formed. 



On microscopical examination intense hyperemia and partial hemorrhagic infil- 

 tration is visible at the beginning; this soon gives way to a purulent infiltration 

 which proceeds from the center, while the renal structure is obliterated and the 

 parenchyma partially atrophied. Still later fibroblasts appear in the ])urulent 

 infiltrated tissue, young granulation tissue is formed which, in the cicatricial stage 

 of the disease is transformed into connective tissue. 



Nephritis apostematosa (abscessus renis). In this form small pus 

 foci become confluent and form larger abscesses or an abscess forms 

 from an embolus; variable portions of the tissue of the kidney break 

 down or the entire kidney is changed into a sac filled with pus (pyone- 

 phrosis). Larger pus foci occur, usually numerously, in horses by 

 metastasis of stranges and in calves from unknown causes (possibly 

 by umbilical infection). The connective tissue is increased around 

 older abscesses but atrophies later, the inflammation of the surround- 

 ing tissue becoming chronic. 



Symptoms. The clinical picture of purulent nephritis is 

 characterized by its variability. It is evident that the symptoms 

 will be different when the nephritis develops as a local affection 

 and when it occurs as a part of general sepsis or pyemia. 

 Variations also occur according to the duration, the number 



