42 



Scientific Proceedings (95). 



showed that as the permeability of the kidneys is lowered in con- 

 ditions of renal insufficiency this becomes evident in the blood; 

 first, by a retention of uric acid, later, by that of urea, and lastly 

 by that of creatinine, indicating that creatinine is the most 

 readily eliminated of these three nitrogenous waste products. 1 

 Theoretically, the amount of the increase of the creatinine in the 

 blood should be a safer index of the decrease in the permeability 

 of the kidneys than the urea, for the reason that creatinine on a 

 meat free diet is entirely endogenous in origin and its formation 

 (and elimination normally) very constant. Apparently the 

 kidneys are never able to overcome the handicap of a high creati- 

 nine accumulation, for, we soon found that those cases in which 

 the creatinine had risen above 5 mg. per 100 c.c. of blood rarely 

 showed any marked improvement and almost invariably died 

 within a comparatively limited time. 2 On the other hand, cases 

 with high figures for urea, but without marked creatinine retention, 

 generally showed improvement. 



We have now had the opportunity of following 94 cases with 

 creatinine values of 5 mg. or more. The outcome has been; died 

 83, unknown 3, unchanged 4, improved 2 and recovered 2. The 

 two cases classified as recovered were acute cases in which the 

 creatinine remained over 5 mg. for only a few days. Of the 83 

 known dead, 80 per cent, died in less than two months, although a 

 few cases have lived as long as a year. There were a good many 

 cases who were able to be up and about, and some who showed 

 considerable clinical improvement. The creatinine gave us a 

 better prognostic insight into these cases than either the blood 

 urea or phthalein tests which were made simultaneously. It is 

 our opinion that in these advanced cases of nephritis the blood 

 creatinine furnishes a more reliable prognosis than any other test 

 we possess. 



1 Myers, Fine and Lough, Arch. Int. Med., 1916, xvii., p. 570. 



2 Myers and Lough, Arch. Int. Med., 1915, xvi., p. 536. 



