Chronic Parenchymatous Nephritis.
A good deal of confusion is connected with this name, for the reason that many authors include in this one class all the large white kidneys except the waxy ones, and such kidneys present a variety of lesions. There are, however, a moderate number of cases in which the morbid changes are confined to the epithelium of the tubes and to the Malpighian bodies. All the kidneys, no matter what their gross appearance may be, which present changes in the stroma and blood-vessels, as well as in the tubes, belong properly to the class of chronic diffuse nephritis. I confine the name of chronic parenchymatous nephritis, therefore, to those kidneys in which the inflammatory process runs a chronic course and is confined to the epithelium of the tubes and the Malpighian bodies.
LESIONS.—The kidneys are regularly increased in size, often weighing sixteen or twenty ounces. The capsules are not adherent, the surface of the kidney is smooth. The cortex of the kidney is thick and white, with white striæ running into the bases of the pyramids; the pyramids are large and red. The epithelium of most of the tubes and of the Malpighian capsules is swollen, granular, and detached. Cast-matter is present in the tubes. There may be an increase in the number of the small cells which cover the tufts of vessels in the Malpighian bodies.
ETIOLOGY.—This form of nephritis is not very common. It may follow acute parenchymatous nephritis and chronic congestion of the kidney; it is one of the complications of chronic pulmonary phthisis, and it occurs as an idiopathic disease.
SYMPTOMS.—There is a good deal of variety in the different cases as to the quantity and specific gravity of the urine. Usually the quantity is somewhat diminished, and the specific gravity is between 1020 and 1030.
Albumen is regularly present in considerable quantity, but it may be scanty, and may even disappear altogether for a time. Hyaline and granular casts are usually present, but in small numbers.
Dropsy is a regular symptom, and often goes on to general anasarca, although the degree of the oedema varies from week to week. Occasionally a case will run its course without any dropsy.
The functions of the stomach are disturbed, and the patients suffer from loss of appetite, nausea, and vomiting.
Muscular twitchings, convulsions, stupor, and coma only occur in the very severe cases.
Dyspnoea is often produced by the dropsy, sometimes is simply a nervous phenomenon.