DROPSY OF THE KIDNEY 405 



DROPSY OF THE KIDNEY. 



Hydronephrosis. Cystic Kidney. 



Definition. A chronic condition in which urine collects in 

 the pelvis of the kidney or the kidney proper, leading to 

 functional disturbances of the organ. 



Etiology. (a) Mechanically by some impediment to the 

 flow of urine from one or both kidneys. The urine is dammed 

 up in the pelvis of the kidney with a gradually increasing 

 pressure. As the pressure of the urine increases, the loss in 

 the secreting power of the organ is more manifest, and event- 

 ually if the pressure is constant or increased, the function 

 of the organ may be entirely lost. The parts of the urinary 

 passages affected by the impediment gradually dilate ' and 

 the renal tissue atrophies, so that the condition anatomically 

 stops as no more urine is secreted. 



(6) A number of conditions which cause partial stoppage of 

 the flow of urine will cause cystic kidney. The most frequent 

 are: Catarrhal inflammation of the ureters, bladder, or 

 prostate glands; the presence of calculi in some portion of the 

 tract which interferes with the passage of urine. 



(c) Sometimes the condition is congenital; there is either 

 no opening through the ureter, or it is otherwise' anatomi- 

 cally deficient. This allows the urine first formed to accu- 

 mulate until the backward pressure is sufficient to stop renal 

 secretion. 



(d) Compression of the urethra and neck of the bladder 

 by adjacent new growths. The new growths interfere with 

 the flow of urine and cause it to accumulate in the pelvis of 

 the kidney. 



(e) Paralysis of the urinary bladder which allows the 

 urine to collect and lead to back pressure. 



(/) In chronic inflammation of the kidneys some of the 

 urinary tubules become constricted at certain points by the 

 contraction of the interstitial tissue, which undergoes atrophy, 

 causing the canals which are attached to the Malpighian 

 bodies to become dilated. If the urine continues to be 

 secreted it accumulates and forms small retention cysts. 

 These cysts may be found singly or in large numbers in the 



