After the subsidence of the clinical symptoms of nephritis, the patient may be allowed to leave the bed for a few hours during the day, but he must abstain from any bodily exercise. Whenever albumin reappears in appreciable quantities, and red blood corpuscles are found, strict recumbency must be again insisted upon.
(b) Nephritis Due to Diphtheria There occurs frequently in diphtheria a renal disease which clini cally, as well as pathologically, exhibits an entirely different aspect from that of scarlatina' nephritis. According to several statistieal tables, symptoms of nephritis are found in from 15 to 65 per cent. of all cases of diphtheria. This complication, according to Unruh, is an absolutely certain sign of a general infection. The renal damage which follows diphtheria is just as little the result of the direct influence of the bacteria as is the nephritis of searlet fever, but the eau.se is in both cases to be found in the influence of a toxic action.
urine is normal in color. The specific gravity is increased, the percentage of albumin is moderate, and there is a more or less plentiful sediment consisting of hyaline and epithelial cylinders. leueocytes and fat-grain cells. The number of red blood corpuscles is relatively smaller than in scarlatinal nephritis (Fig. 5). Wagner found a larger percentage of blood only in the most seriou.s cases, with gangrenous ehanges in the nasopharynx. The amount of urine is seldom less than 200 c.c. (6? oz.) and anuria of long duration WaS not observed. The slight tendency to (-edema, urfemia, and to se vere general symptoms has been emphasized by all observers.
Pathological most important lesion is found in the parenchyma. IIeubner lays stress upon the fact that the convoluted tubules and the de scending limbs of the loops of Henle, are usually most affected, while the aseending limbs and the intercalary parts are very slightly altered. The collecting tubules also show very early a, shedding of epithelium and obstruction by hyaline casts be ginning near the cortex. The changes in the epithelium con sist in the accumulation of fat drops (see Plates 49-50). In serious eases the epithelium loses its nucleus and shows an indurated appearance. If we
remember the location of the most serious alterations, it is evident that we cannot get a clear idea of them by examining the sediment in the urine, beeause owing to the closeness of the passage through the ascending limbs of the loops, casts and epithelium from this region cannot escape into the urine (Heubner). The fundamental difference in the influence of the scar latinal and the diphtheritic poison upon the kidney is explained by the pathological anatomy. While the scarlatinal toxin has the great est affinity for the vasa, the diphtheritic toxin does not touch them, but only attacks the parenchyma. Experiments also teach us the affin ity of certain toxins for certain portions of the kidney. Paul Ehrlich, for instance, demonstrated that vinylainin causes a eomplete necrosis of the medulla, i.e., of that part which represents an evolutionary unit.
The prognosis of this type of nephritis is favorable. As a rule, recovery takes place in froin one and a half to two weeks, and, according to Heubner, this affection leads to the chronic form less frequently than scarlatina' nephritis. For the treatment, we rcfer to the chapter on scarlatinal nephritis.
(e) Nephritis Due to Other Infections, Intoxications, and of Unknown Etiology Measles is not often complicated by nephritis, but it may appear in the early stage of the disease, and its clinical symptoms and the ana tomical appearances correspond on the whole to scarlatina' nephritis. It is relatively often followed by cedema and uramia.
Nephritis may be a complication of varicella too. This fact was pointed out for the first time by Henoch. The nephritis appears in the second or third week after the eruption of the papules, its hamor rhagie character is more or less pronounced CEdema, uramic symptoms, and even a fatal issue have been described, but the prognosis of the nephritis of varicella is in general a favorable one.
True, smallpox is also occasionally complicated by hamorrhagic nephritis, but the pathognomonie importance of albuminuria appear ing now and then after vaccination has not been as yet fully deter mined (Falkenheirn).