202 DISEASES OF THE KIDNEYS 



Etiology. — This form of nephritis usually develops from the 

 acute parenchymatous, the causes of which have been given. 

 In the horse it may have an embolic origin emanating from 

 the worm aneurysm in the anterior mesenteric trunk. In 

 cattle it sometimes results from pyelitis. In man, sclerosis of 

 the arteries is a common cause. 



Symptoms. — The principal symptom of chronic interstitial 

 nephritis, contrary to the acute and chronic parenchymatous 

 nephritis, is an increase in the quantity of urine voided- by the 

 patient (polyuria). The urine is of low specific gravity 

 (1001 to 1010) and contains little albumin, few tube casts, 

 and renal epithelium. Generally associated with the polyuria 

 are symptoms of hypertrophy of the heart (see this), which is 

 later followed by dilatation of the organ, leading to symptoms 

 of dropsy, such as anasarca, hydrothorax, hydropericardium, 

 and ascites. In some cases uremia may follow with convul- 

 sions and coma. In rare instances blindness results from 

 albuminuria retinitis. 



Prognosis. — The prognosis is bad, as the condition is gener- 

 ally incurable. As the efficiency of the patient (horses) falls 

 below the cost of keeping many of them are destroyed or 

 traded off. 



Treatment. — While in man a palliative treatment which will 

 prolong life is indicated (nitroglycerin, digitalis, strychnin) 

 in animals this does not pay. Otherwise the treatment is 

 the same as for acute parenchymatous nephritis. 



Purulent Nephritis. — Definition. — A suppurative inflamma- 

 tion of the kidneys leading to diffuse pus infiltration or to 

 abscess formation in the organ. 



Occurrence. — This form of nephritis is usually secondary to 

 such diseases as strangles, pyemia, wound infections, etc. 



Etiology. — The causes are pus-producing bacteria which are 

 carried to the kidney either through the blood or come from 

 the bladder or pelvis of the kidney through the urine. Speci- 

 fically staphylococci and streptococci are the principal causes. 

 These bacteria produce in the organ either a disseminated 

 purulent nephritis in the form of large numbers of small 

 abscesses, found principally in the cortex (nephritis punctata), 

 or a few isolated large abscesses (pyonephrosis). In cattle 



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