Both subacute and chronic parenchymatous nephritis show clinically much albumin, many casts, marked edema (except in very emaciated cases), absence of high blood-pressure, and the heart is not enlarged. This condition is caused commonly by chronic tuberculosis, syphilis, sepsis, and malignant tumors. With these clinical symptoms and the history, we may differentiate the nephritis of pregnancy from Bright's disease. Again, acute intestinal nephritis or glomerulonephritis has urinary findings like the nephritides just described, and there may be edema. The heart and the blood-vessels are normal. The cause is usually a pus microörganism, and there may be anemia from the sepsis. In subacute glomerulonephritis, or intestinal nephritis, the urinary findings are marked (much albumin and many casts), anemia is rather constant, the blood-pressure gradually goes up to 180 or 200, edema may be marked or absent. The cause is usually a pus microörganism. Chronic glomerulonephritis shows much epithelium and many casts (sometimes in showers), the blood-pressure is high, the heart is usually somewhat enlarged, there is polyuria and some blood, edema is common (but there are dry cases), albuminuric retinitis is rare, and anemia is marked and secondary. It may be difficult to find the cause of this chronic glomerulonephritis, but there is, as a rule, a history of tonsillitis, septic rheumatism, endocarditis, a true influenza, or the like infection. Primary arteriosclerotic contracted kidney shows hypertension and secondary circulatory disturbance. The urinary findings are comparatively slight and transient, and there is little or no anemia. The development is insidious, and the etiology is not known.
There is evidence of late to find a septic cause for most of the nephritides, such as infectious fevers, pyorrhea of the teeth, and like bacterial intoxications; in pregnancy the nephritis may be toxemic from sources that are not bacterial. It is extremely difficult, and not seldom impossible, to make any differentiation, as has been said. When the child is viable, whether the uterus should be emptied or not must be decided for the individual case; no general rule can be set down to cover all conditions.