UREMIA 537 



100 mg. per 100 cc, and they are rarely absent when the concen- 

 tration exceeds 200 nig.''- With these high blood nitrogen figures 

 there is also an increase in nonprotein nitrogen in the; tissues CFoster)^^ 

 and metabolism studies show nitrogen retention of consi(lera})le degree, 

 sometimes over 1 gram retention when the intake is but 10 grams per 

 day. 



Along with the other nitrogenous constituents the uric acid is in- 

 creased from a normal 2 to 3 mg. up to 7 to 10 mg., and even higher. 

 Creatinin rises from 1 to 2 mg. up to 5 to 20 mg.^* On the other 

 hand the amino-acid nitrogen may be normal in the blood even with 

 extremely high nonprotein nitrogen figures,'^ although sometimes it is 

 much increased, as high as 30 mg. amino acid N having been found 

 b}' Bock^^ in uremia (the normal figure being 7 mg.). FeigP^ reports 

 finding as high as 125 mg. amino-N, with frequently 60 to 85 mg. The 

 retention of various substances varies directly with the solubility and 

 diffusibility of the substances, so that with renal disease we first get 

 retention of uric acid, then urea, and last of creatinin (Myers). '^ 

 Ammonia nitrogen may show a slight increase, rising in half of Fos- 

 ter's cases from the normal 0.5 mg. to from 0.7 mg. to 2.2 mg. per 100 

 cc. Indicanemia may also be present but it is not a toxic factor 

 (Dorner)." The blood normally contains about 0.05 mg. per 100 

 cc; in uremia it may rise to 0.2 mg., and as much as 2.2 mg. has been 

 found in one case.^^ 



The Pathogenesis of Uremia. — The fact that the highest figures 

 for non-protein nitrogen are usually found in uremia might be accepted 

 as proving that uremia is caused by poisoning with these metaboHtes, 

 were it not for certain contradictory observations. 



(1) Occasionally quite typical attacks of uremia are observed without high 

 nonprotein nitrogen figures for the blood, even as low as 28 mg. having been re- 

 corded in a fatal case.^* 



(2) Extremely high nonprotein nitrogen content may be observed without 

 uremia. Thus, Tileston and Comfort found 169 and 150 mg. in two cases of acute 

 intestinal obstruction without uremic symptoms, and similar results have been 

 obtained in bichloride of mercury poisoning,'"* and mechanical anuria. The occur- 

 rence of albuminuric retinitis also seems to bear no relation to the nitrogen retention 

 (Woods). 



" Hewlett, Gilbert and Wickett, Arch. Int. Med., 1916 (18), 636. 



" Arch. Int. Med., 1919 (24), 242. 



»* See Myers and Fine, Arch. Int. Med. 1915 (16), 536; 1916 (17), 570. 



»5 Foster, Arch. Int. Med., 1915 (15), 356. 



36 Jour. Biol. Chem., 1917 (29), 191. 



" Deut. Arch. klin. Med., 1914 (113), 342; Rosenberg, Arch. exp. Path., 1916 

 (79), 260; Tscherkoff, Deut. med. Woch., 1914 (40), 1713; Rev. M6d. Suisse Ro- 

 mande, 1918 (38), 15. 



2« Hass, Deut. Arch. klin. Med., 1916 (119), 177. 



3^ There are few who would go to the extreme of Strauss (Berl. klin. Woch., 

 1915 (52), 368) and limit the term uremia to cases showing a high non-i)rotcin 

 nitrogen in the blood, no matter what the sj-mptomatology and pathology may 

 be. A totally different viewpoint is expressed by Reiss, Zeit. kUn. Med., 1914 

 (80), 97, 424, 452. 



^» See Foster, Arch. Int. Med., 1915 (15), 754. 



