33 St. Bartholomew's Hospital Reports, xiv. p. 16.
The characters of the urine in acute rheumatism are tolerably uniform, but far from constantly so. Its quantity in the majority of cases is reduced, frequently not exceeding twenty-four ounces per diem, and occasionally not exceeding fourteen. This is owing in some degree to profuse sweating, but also, as in other febrile affections, to retention of water. Its density is usually high—1020 to 1030, or even 1035—which is due chiefly to its concentration, and not, as has been generally supposed, mainly to an increase in the total solids excreted.34 Its color is a very dark red or deep reddish-yellow, partly from concentration; but it is yet not known whether the deep hue is partly from increase of the normal pigments or of one of them (urobilin),35 or from the presence of some abnormal coloring matter. Its reaction is generally highly acid, and continues so for many hours after its discharge, unless in subacute cases, when it is occasionally neutral or sometimes alkaline at the time of its escape, or becomes so in a very short time afterward. It is commonly toward the decline of the attack that the urine becomes neutral or alkaline. As a very general rule, the amount of urea and of uric acid excreted during the febrile stage exceeds what is physiological, and begins to decline when convalescence commences; but this may be reversed (Parkes,36 Lede,37 Marrot38). The sulphuric acid is notably increased (Parkes), the chlorides often diminished and sometimes absent, and the phosphoric acid very variable (Beneke, Brattler39), but usually lessened (Marrot).
34 See Guy's Hospital Reports, 3d Series, vol. xii. 441.
35 Jaffe, Virchow's Archiv, xlvii. 405, quoted in Ziemssen's Cyclopæd. Prac. Med., xvi. 41.
36 On Urine, p. 286.
37 Recherches sur l'Urine dans le Rheumatisme Artic. Aigue, Paris, 1879.
38 Contribution à l'Étude du Rheumatisme Artic., etc., Paris, 1879, 41.
39 Quoted by Parkes, op. cit., 290.
During convalescence the urine increases in quantity, while, as a general rule, the urea and uric acid lessen relatively and absolutely, and the chlorides resume their normal proportions to the other ingredients. The reaction frequently becomes alkaline, and the specific gravity falls considerably, although not always as soon as the articular inflammation subsides. Temporary albuminuria occurs very frequently in the febrile and occasionally in the declining stage, but generally disappears when convalescence is completed. It obtained on admission in 8 out of 43 cases lately reported by Dr. Greenhow.40 A more abiding albuminuria, due very rarely to acute parenchymatous nephritis, may be met with (Johnson, Bartels, Hartmann, Corm). Blood, even in considerable amounts, has also rarely appeared in the urine,41 sometimes in connection with embolic nephritis and endocarditis, for such appear to have been the nature of Rayer's nephrite rheumatismale.42
40 Lancet, 1882, i. 913.