178 SWINE PRACTICE 



Tucks reported 0.67 per cent of cystic kidneys in over six thousand 

 hogs examined, and the writer found this condition in the kidneys 

 of twenty-nine swine in three thousand examined. The condition 

 may affect one or both kidneys. 



Etiology.— Ohstr-acted outflow of urine is the primary cause of 

 cyst formation in the kidney. The anatomical arrangement of the 

 openings of the ureters into the bladder predisposes to their ob- 

 struction and therefore to the accumulation of urine in the kidney 

 pelvis. Renal and pelvic calculi and inflammatory products oc- 

 casion obstruction of collecting tubules and favor cyst formation. 

 Cicatrization of newly formed fibrous tissue may obstruct the out- 

 flow of urine and cause cyst formation. Complete obstruction of 

 the ureters or kidney pelvis will not as a rule result in hydrone- 

 phrosis, as this condition results in a compensatory activity on the 

 part of the normal kidney. 



Lesions. — Hydronephrosis may occur as cysts in the renal sub- 

 stance or the kidney may be practically replaced by a variable-sized 

 watery bag. The cysts- vary in size from a pinhead to an inch in 

 diameter. There may be myriads of the small cysts scattered through- 

 out the kidney but occurring primarily in the cortical portion. Ths 

 larger cysts are usually not numerous and they frequently repre- 

 sent the fusion of small cysts. The cysts have a bluish-white color, 

 are definitely surrounded by a distinct capsule, and the content is 

 thin and watery. The' kidney substance between the cysts is 

 atrophied, due to pressure. In extreme cases the kidney capsule 

 may serve as the cystic capsule, the entire mass being much enlarged 

 and the small atrophied kidney floating within. Richter reported 

 a case of a hydronephrotic kidney weighing over ninety pounds. 



HBMOURHAGE 



Kidney hemorrhage is relatively common in swine, not as a primary 

 condition, but associated with some disease. The extravasated blood 

 may escape into the uriniferous or collecting tubules, producing 

 hematuria, or it may escape into the kidney tissue. 



Etiology. — Injury of the capillaries, either glomerular or tubular, 

 may result in hemorrhage. The vessels are most frequently damaged 

 by chemical substances that are being eliminated in the urine or by 

 products of bacteria produced in the kidney or elsewhere in the 

 body. 



