Diagnosis. Acute renal congestion is distinguished from nephritis by the suddenness of the onset, the absence of fever and the comparative absence of tenderness of the loins, and of tubular casts.
From hæmoglobinæmia it is distinguished by the absence of the conditions under which that affection appears:—the previous heavy work and full rich feeding, the day or more of complete rest on full ration, and the sudden exercise following. The hind parts in hæmoglobinæmia are benumbed, paretic, or paralytic and not unfrequently rigid and swollen, and the brownish or reddish urine contains hæmoglobin in amorphous particles, and not red blood globules and sanguineous tubular casts as in renal congestion.
From laminitis it is distinguished by the absence of high fever, by the absence of the advance of the fore feet resting on the heels, of the heat and tenderness of the feet, by the ability to bear the lifting of one fore foot, or the tap of a hammer on the toe, by the lack of improvement after the first few steps as is seen in laminitis, and by the absence of the strong pulsations in the digital arteries.
From indigestion it is distinguished by the absence of the history which leads up to that condition, of abdominal tympany, of rumbling, of impaction and of frequent attempts to defecate, and by the presence of the stiffness, straddling, and the blood globules and albumen in the urine of low density.
Prevention. This must be sought by the avoidance of all the factors of causation:—auto-intoxication in contagious diseases, excessive renal irritation from the injudicious use of diuretics, or the accidental ingestion of irritant or acrid diuretic plants or waters, or musty fodders, or the sudden change to the succulent, watery, first vegetation of spring, or of exposure to cold, wet, or damp, in all their forms, or of direct injury to the back or loins by blows, shocks, or violent exertions.
Treatment. Trasbot and Cadeac strongly recommend venesection, and at the very outset in specially acute cases the sudden lessening of the arterial and capillary tension, by this potent means, may furnish the opportunity for the capillaries of the glomeruli and tubes to regain their normal tone, and thus contribute to a speedy abortion of the affection. If resorted to at all it should be made in a full stream from the jugular, so as to secure the fullest and most prompt result with the least possible effusion of blood.
Much, however, must depend on the attendant conditions. In toxin poisoning following on an infectious fever, the already existing debility will sufficiently forbid a resort to the lancet, and we must seek elimination by the bowels, the skin or even the kidneys. Antiseptics, too, are in order if there appears any ground for suspicion of the action of infecting agents. Some cases will recover promptly under diffusible, stimulant diuretics such as spirits of nitrous ether, which by stimulating the circulation in other organs and especially the skin, appears to relieve the kidney and solicit normal secretion. But most veterinarians dread the stimulus and irritation and prefer small doses of refrigerant diuretics: bicarbonate of soda 4 drs., saltpeter 2 drs. or the tartrates, citrates or acetates of the alkaline bases. In case of irritation by acrid diuretics, but especially by cantharides, camphor 2 drs., has been found to be particularly soothing, and next to this, bromide of camphor or bromide of potassium 1 to 2 drs. may be resorted to. Zundel prescribes acidulated camphorated drinks. The free use of mucilaginous drinks, such as boiled flax seed; and the persistent application of fomentations or wet compresses to the loins are of equal value in soothing irritation. Sinapisms may advantageously follow the local emollients.
Laxatives act with less promptitude than diuretics, but on the whole constitute a safer treatment, since they secure elimination and derivation without risk of irritation to the kidneys. The oils: castor 1 to 2 pints, linseed 2 pints, or olive 2 pints, are especially to be recommended in this respect, but l’Homme advises manna, and calomel may also be used as a substitute. Injections of warm water are valuable in unloading the rectum and colon, soothing the kidneys and soliciting peristalsis.
A restricted amylaceous diet is essential, and a warm stall or abundant clothing. Grooming or active rubbing of the skin tends to active derivation and often materially relieves. The case should not be abandoned until a day or two after the urine has returned to the normal, and for some time special care should be taken of the diet, stabling and work.