Amyloid degeneration is described in much the same way as by other authors.
Rindfleisch describes : 1. Acute Parenchymatous Nephritis.—In the milder form the kid ney is of normal size, the surface smooth, the cortex of a yellowish gray color. There is a moderate degree of cloudy swelling of the epithelium of the convoluted tubes.
In the severer form the kidney has the same appearance, but is increased in size and the cortex is thickened.
Both these forms occur with the acute exanthemata, typhus fever, pyremia, etc.
2. Diffuse Interstitial Nephritis.—This corresponds very closely with the description given by Klebs.
He states that the disease may begin as a parenchymatous ne phritis, and afterward become interstitial, but that the two forms also occur independently of each other.
Amyloid degeneration is usually accompanied by interstitial ne phritis. The amyloid degeneration is the primary change, and the nephritis follows it as a secondary lesion.
Rosenstein describes : 1. Chronic Congestion of the Kidney.—This condition is described in much the same way as by the preceding authors.
2. Catarrhal Nephritis.—The kidney is of normal size, or slightly enlarged; in severe cases congested and mottled with small ecchy moses. The process begins at the apices of the pyramids, which are at first congested, afterward pale. After a time we find the pyramids divided into red and white striae, running from the apex to the base of the pyramids. The red strim are the portions more recently con gested; the white are the tubes distended by an increase of epithelium.
The urine contains a little albumin, hyaline, granular, and epithe lial casts and blood-globules.
The symptoms during life are not marked. The lesion is seldom primary. It may follow catarrhal inflammation of the urethra, blad der, or ureters; the use of cantharides, copaiba, or cubebs; typhoid or typhus fever, cholera, etc.
3. Diffuse Nephritis, Parenchymatous Nephritis, Bright's Disease, Granular Degeneration of the Kidney.—This form has three stages.
The first stage is that of hyperemia. The kidney is of. normal
size, or enlarged, congested, and red; there is blood in the tubes, and the epithelium of the convoluted tubes is swollen.
The second stage is that of exudation. The kidney is enlarged, the cortex pale, the pyramids red. The epithelium of the convoluted tubes is swollen and granular. The tubes are dilated and contain casts. There is usually an increase of cells in the interstitial tissue.
The third stage is that of atrophy. The kidney becomes smaller, its surface nodular. The atrophy may take place without any change in the interstitial tissue, simply as a result of the destruction of the epithelium. Usually, however, the retraction of the new interstitial tissue assists in producing the atrophy.
The epithelium is granular or fatty. The Malpighian bodies are atrophied, their capsules thickened and surrounded with new connec tive tissue. The basement membranes of the tubes are thickened, and are accompanied by bands of connective tissue. The intertubu lar capillaries are partly dilated, partly small and fatty.
The atrophy consists, therefore, in a suppression of the function of a number of the tubes, with obliteration of some of the blood-ves sels and increase of the interstitial tissue.
Either process, that in the epithelium or that in the connective tissue, can occur separately, but they are usually combined.
4. Amyloid Degeneration. —Rosenstein describes this form in much the same way as other authors. He regards the degeneration of the vessels only as a complication of the parenchymatous and inter stitial change.
5. The Fatty Kidney.—There is an infiltration of the epithelium with fat, or a fatty degeneration. The condition is described in the same way as the diffuse granular degeneration of Klebs.
Weigert divides Bright's disease into parenchymatous degenera tion and true nephritis. He does not distinguish between interstitial and parenchymatous forms of nephritis, but believes that in all cases the disease begins with degeneration of the epithelium, which is fol lowed by inflammatory interstitial processes.