SUPPURATIVE NEPHRITIS AND PERINEPHRITIS. 537 



Treatment also comprises certain prophylactic precautions. As the 

 infection which produces pyelo-nephritis originates in the genital tract, 

 it is desirable to protect all animals in a receptive condition (those about 

 to calve or having recently calved) from infection ; hence, when the 

 disease is detected in a cow-shed, the patients should be isolated, and 

 the shed thoroughly disinfected. 



SUPPURATIVE NEPHRITIS AND PERINEPHRITIS. 



Suppuration of the kidney may occur under two conditions. In the 

 majority of cases such suppuration occurs as a complication of pyelo- 

 nephritis ; less frequently it is the consequence of infection from within 

 or infection of adjacent parts, leading to the formation of an abscess. 



When it results from an ascending infection the kidney becomes 

 swollen, congested and inflamed, and soon displays localised minute 

 haemorrhages. Pus then forms within the calices, in the large straight 

 tubes, and diffuse suppuration invades all the uriniferous tubules. The 

 enlarged kidney is yellowish, firm under the knife, and when sections are 

 compressed pus exudes from the openings of the tubular canaliculi. 



When suppurative nephritis has resulted from accidental infection 

 of internal origin, an abscess is found to have produced more or less 

 extensive atrophy of a portion of the kidney while not affecting the rest 

 of the organ. 



It is only in those favourable cases where the renal abscess opens 

 into the pelvis that suj)puration may invade the whole of the kidney, 

 producing diffuse suppurative nephritis by secondary infection of the 

 uriniferous tubules. Such complications are rare. Usually the abscess 

 empties through the pelvis, and recovery may occur. 



More frequently suppurative pyelo-nephritis develops, together with 

 ureteritis, cystitis, dilatation of the ureters, dilatation of the pelvis of 

 the kidney, and dilatation of the collecting tubules of the pyramids, the 

 final stage resembling the lesions of pyo-nephrosis. 



Perinephritis and perinephritic cellulitis, i.e., inflammation with or 

 without abscess formation in the connective tissue and adipose layer 

 surrounding the kidney, always occur in cases of suppurative nephritis 

 or pyelo-nephritis. Such inflammations may also, in exceptional cases, 

 follow direct mechanical injury, but they almost invariably represent 

 complications, the organisms infecting the kidney passing through the 

 tissues and the layer of fibrous tissue, or extending by the lymphatic 

 paths, finally attaining the fatty tissue surrounding the kidney and there 

 undergoing multiplication. The fatty tissue is infiltrated with reddish 

 serosity, is inflamed, and may become the seat of large abscesses com- 

 municating with or separate from the abscesses of the kidney itself. 



