Nephritis. 



5 



3 (1067) 



The significance of the uric acid, urea and creatinine of the blood 

 in early and late nephritis. 



By V. C. Myers, M. S. Fine and W. G. Lough. 



[ From the Laboratory of Pathological Chemistry and the Department 

 of Medicine, New York Post-Graduate Medical School and 

 Hospital.] 



Typical cases of gout show, as a rule, blood uric acid values 

 from 2 to 5 times the normal. The amounts of urea and creatinine 

 are normal or in the case of urea, only slightly above normal. 

 Many early cases of nephritis, especially of the interstitial type, 

 give blood pictures which differ little from those of gout. The 

 uric acid findings are quite as high and the urea content varies 

 from only slightly above to more than double the normal amount. 

 The creatinine is only slightly increased. As the condition of 

 cases of this type becomes more severe, the retention of urea 

 increases, until we have high values for urea as well as for uric acid. 

 If improvement takes place the concentration of urea gradually 

 falls until the picture is that of the preceding group. If, on the 

 other hand, the case goes on to a fatal termination, the retention 

 of uric acid and urea is followed by that of creatinine, the concen- 

 tration of which may reach twenty times the normal. Here the 

 phthalein output is practically zero. 



From the foregoing it would appear that as the permeability 

 of the kidney is lowered it becomes evident in the blood, first, 

 by an increase in the uric acid, second, by that of urea and lastly, 

 by that of creatinine. That this should be the case seems quite 

 plausible when we consider the ease of excretion of these con- 

 stituents, as determined from a comparative nitrogen partition 

 of normal urine and blood. Uric acid nitrogen forms 2 per cent, 

 of the non-protein nitrogen of both urine and blood, urea nitrogen 

 about 85 per cent, in urine but 50 per cent, in blood and creatinine 

 nitrogen 5 per cent, in urine but only 2 per cent, in blood. 



