The total non-protein nitrogen of the blood in nephritis and allied conditions

Abstract

The following summary covers the results of our study of the non-protein nitrogen of the blood by Folin's methods in a series of fifty-nine hospital patients. Our main concern has been with nephritis but we have examined the blood in many other conditions as opportunity offered.

The patients group themselves into four divisions:

I. Those showing no disturbance of renal function (17 cases).

II. Those with marked cardiovascular disease of some type, most of which showed urinary changes the result of renal congestion (11 cases).

III. Those showing nephritis (23 cases).

IV. Those in which certain features would lead one to suspect nephritis, but in which the existence of nephritis is not borne out by other findings (8 cases).

Our patients of Group I, suffering from a variety of acute and chronic diseases, but without evidence of disturbance of renal function, showed a total nonprotein nitrogen in the blood varying from 16 to 43 milligrams per 100 c.c. From 50 to 60 per cent. of this was in the ammoniaurea fraction. In the patients with cardiovascular disease with renal congestion, but without evidence of other renal lesion there was no increase of the nonprotein nitrogen in the blood, nor alteration of the ammoniaurea percentage, although albuminuria, casts and some impairment of the phenolsulphonephthalein elimination were usually present.

In that type of chronic nephritis characterized by marked albuminuria, cylindruria and edema, there were similar findings. In that type of chronic nephritis associated with hypertension, the nonprotein nitrogen was increased, ranging from 40 to 181 milligrams per IOO c.c., and the percentage of the ammoniaurea fraction was usually higher than in non-nephritic cases. The nitrogen values in these patients were subject to rapid fluctuations in the course of a few days and clinical improvement was associated with a fall in the non-protein nitrogen content.