It seems to me probable that the so-called uræmic symptoms are most frequently due to disturbances of the circulation of blood. Such disturbances of the circulation produce in the brain cerebral symptoms; in the lungs, dyspnoea; in the stomach, vomiting; in the kidneys, suppression of urine.
With the atrophic form of chronic diffuse nephritis we have all the conditions necessary for an irregular circulation—hypertrophy of the left ventricle, diseased arteries, and hydræmic plethora. In the other cases with cerebral symptoms there are also conditions present capable of interfering with the circulation.
Acute Parenchymatous Nephritis.
PATHOLOGICAL ANATOMY.—The lesions of acute parenchymatous nephritis vary with the intensity of the inflammatory process.
(1) Mild Cases.—The kidneys are of normal size and weight. The capsules are not adherent, the surface of the kidney is smooth, the cortex is of normal color or rather pale. The epithelial cells lining the convoluted tubes are swollen and granular.
(2) More Severe Cases.—The kidneys are increased in size. The cortex is thick and whitish, with white striæ extending in to the bases of the pyramids. The epithelium of both the convoluted and straight tubes and of the Malpighian bodies is swollen and granular. There is cast matter in the tubes.
(3) The Most Severe Cases.—The increase in the size of the kidneys is still more marked. The epithelium of most of the tubes is not only swollen and granular, but is also in many tubes detached from their walls. A great deal of cast-matter, and sometimes blood, is found in the tubes. There are no changes in the stroma or in the blood-vessels of the kidneys.
ETIOLOGY.—Acute parenchymatous nephritis occurs both as a primary and secondary lesion. The idiopathic cases occur without assignable cause or after exposure to cold, and are not very common. The secondary cases are seen very frequently. They complicate a variety of other diseases. With pneumonia, typhus fever, and typhoid fever the nephritis is usually of mild type. With yellow fever and acute atrophy of the liver the nephritis is very severe. With scarlatina, diphtheria, pyæmia, peritonitis, phosphorus- and arsenic-poisoning the severity of the nephritis varies with the different cases.
SYMPTOMS.—(1) The Idiopathic Cases.—The urine is diminished in quantity and may be suppressed; its specific gravity continues nearly normal; it contains albumen, usually in large amounts, sometimes blood: in some cases very few casts are seen, in others there are large numbers of hyaline, granular, and nucleated casts.