168 DISEASES OF THE URINAB Y AND SEXUAL APPARATUS. 



shape. They are generally surrouuded by a red circle. When 

 the spot is examined under the microscope there are swarms of 

 micrococci in the centre of the mass, and it is reasonable to believe 

 that these are the cause of the abscess. Only in rare cases do the 

 abscesses become confluent, and when they do they form large pus- 

 centres that, as a rule, cause death. When the abscess forms in 

 the pelvis of the kidney the pus extends into the straight urinary 

 canals — in some cases as far as the surface of the kidney — and is 

 indicated by a protrusion or elevation of the external surface, which 

 is yellowish in the centre and surrounded by a circle of yellowish 

 points. When large abscesses are formed from these, becoming 

 confluent, the whole kidney may become altered into one large 

 abscess. The covering capsule of the kidney becomes thickened and 

 holds the abscess with its contents (pyonephrosis). In the early 

 stages, where the micrococci have just collected in the ui-inary 

 canals, and have started to form abscess-centres, it makes a verj^ 

 interesting study. 



Where there is a formation of a perinephritic abscess in the region 

 of the kidney caused by traumatic causes, from purulent abscess, 

 from purulent pyelitis, or abscess in the neighboring organs, it may 

 lead to the formation of considerable pus. 



Clinical Symptoms and Therapeutics. The symptoms of 

 abscess of the kidneys may not differ to any great extent from 

 chronic nephritis. The abscess of the kidney occurring in pyemia 

 is only seen on post-mortem. The symptoms of pyelonephritis are 

 also completely disguised by the preceding symptoms of purulent 

 cystitis. Treatment is, therefore, useless. 



Perinephritic abscesses may become so large that they form a 

 tumor-like body in the lumbar region, and the pus can be detected 

 under the skin, in some cases so large that it fluctuates. When 

 such is the case, and we have confirmed our diagnosis by means of 

 an exploring needle, the sac should be emptied by an aspirator 

 or make a fairly large opening and empty the abscess of its con- 

 tents and fill it with au antiseptic dressing. If the kidney itself 

 is not directly affected by the abscess, we may expect a quick 

 recovery under good antiseptic conditions. (See treatment of 

 wounds.) 



