320 Renal Edema [Dec. 



only an expression of a water retention which usually begins long 



before the occurrence of external edema. He believes, of course, 



that when the kidneys are unable to excrete salt, water has to be 



retained with the salt to keep the tissue fluids as nearly constant in 



composition as possible. 



From the great variety of clinical cases of edema, it is obvious, 



however, that this is only one of many causes of edema. Many 



of the other causes have nothing to do with the composition of the 



body fluids and have no effect on the blood. Thus, in the edema 



due to stasis (whether local, as in injuries of veins and lymphatics) 



or general, one finds only such blood changes as are secondary to 



the stasis. 



VI. RENAL EDEMA 



Herman O. Mosenthal 



The dropsy which occurs as a Symptom of kidney disease pre- 

 sents certain characteristics which differentiate it to some extent 

 from other varieties of edema. There is puffiness about the eyelids 

 and face on waking in the morning; during the day, while the pa- 

 tient is in an upright position, the ankles swell and this swelling 

 gradually creeps upward toward the knees. The genital organs are 

 frequently involved early in the disease. It is evident that some of 

 these edematous accumulations are influenced by gravity while 

 others are not. That mechanical factors are not sufficient to ac- 

 count for them is further emphasized by the fact that the edema 

 is occasionally localized in atypical situations, as for instance the 

 ehest wall, the arms or the pleural cavity. 



The fluid spreads from these areas, involving the entire skin 

 and subcutaneous tissues. This condition is spoken of as anasarca. 

 Transudation into the peritoneal, pleural and pericardial cavities 

 occurs only at a later period. The order of these events must be 

 borne in mind since in experimentally produced edema the anasarca 

 frequently appears last instead of first or not at all. 



Attempts have been made to trace an etiological relationship 

 between the glomeruli or the tubules of the kidney and edema. On 

 the supposition that the former excrete the fluid portions of the 

 urine while the latter are mainly responsible for the elimination of 



