With interstitial nephritis there is an exudate into the interstitial connective tissue between the tubules, and into the tubules, forming hyalin casts. The epithelium of the tubules are swollen, granular, opaque and desquamating.
In suppurative nephritis may be found all stages of abcedation from minute points, gray or yellow, and only just visible to the naked eye, in the midst of the deep red congested tissues, through the larger white suppurative areas, to the extensive abscess formed by a coalescence of the many, the intervening tissue having broken down by a necrotic disintegration. In the earlier stages the pus infiltrates the parenchyma so that it may be comparable to a sponge filled with this liquid.
Treatment. The first consideration is rest, with a warm building or clothing to solicit the action of the skin and lessen the work of the kidneys. Warm summer weather is favorable, or we should secure a sunny, comfortable, loose box, or a building heated by a stove. In default of this, warm woolen blankets, hood and leg bandages should be secured. If the case is mild enough to allow of appetite, the food for herbivora may be green food in summer and carrots, beet, turnip, potato or ensilage in winter. The dog may have buttermilk or sweet milk or mush and milk. Meat is objectionable because of the amount of urea and other urinary products which it produces.
Trasbot strongly recommends general bleeding in strong, vigorous horses and cattle, attacked by the disease in an acute form, but deprecates it in the lymphatic, fat, or debilitated.
Omitting the general bleeding, one can always find a good and safe alternative in bleeding the animal into his own tissues. Shaving the loins and cupping has often an excellent effect. An approach to this may be had by vigorous rubbing by several men at once, of the limbs and the whole surface of the body, by warm fomentations over the loins by means of spongio-piline or surgeon’s cotton covered with dry blankets, or by winding a hose round the body through which warm water is forced, or finally by a bath of steam or hot air, or in small animals of warm water. The dog may be placed in a bath of 80° or 90° F., which is allowed to gradually cool to 65° or 70°. In all these cases the greatest care must be taken to avoid chill when the animal is taken out. He should be quickly rubbed dry in a warm room and blanketed.
Counter-irritants act in the same way, and mustard or hot water hotter than the hands can bear may be applied. Turpentine, cantharides and other diuretic counter-irritants must be carefully avoided. An old practice of laying a freshly removed sheep skin over the loins, with the flesh side inward, often causes a distinct exudation, thickening of the skin and derivation.
A damp cloth, laid across the loins and thoroughly covered with dry to prevent any evaporation and chill, will usually give great relief and may be kept on for days.
Internal medication must at first be mainly anodyne, laxative and diaphoretic. The two latter classes are at once derivative and eliminating, carrying out through other channels, waste products that would otherwise have taxed the kidneys.
Among anodynes, the bromide of camphor (horse, 1–2 drs., dog, 2 to 5 grs.), bromide of potassium (horse, 1 dr., dog, 1 to 3 grs.), or hyoscyamus may be used, and repeated twice daily.
Purgatives must be restricted to such as have no tendency to act on or irritate the kidneys. Castor oil, or sweet oil for the larger animals, or for the dog senna or jalap, may be given every morning to secure free movement.