Cases destroyed as eating their heads off. Causes: sequel of acute
nephritis, swill, lead, experimentally, microbian invasions, toxins,
metastatic embolism, extension from aortic disease, sclerostoma,
nitrogenous overfeeding, toxins of putrid food, or cryptogams,
valvular disease of the right heart, rheumatism, heaves, calculus,
starvation, debility, retention of urine. Symptoms: emaciation, flabby
muscles, lack of vigor, stiff loins and quarters, short step,
straddling, fatigue under slight exertion, groaning in trot, or in
turning, droops when mounted, slow to rise on hind limbs, poor
capricious appetite, anæmia, stocked legs, dropsies, urine of lower
density, albuminous, with granular epithelium and casts, abundant in
early stages, scanty with weakened heart and degenerated kidneys.
Secondary palpitations, bronchial catarrh, pneumonia, hemorrhage,
stupor, lethargy, vertigo, etc. Lesions: recent cases, kidney large,
cortex firm, capsule adherent, with granular fatty debris, and tubular
casts; old cases, kidney contracted, fibroid, glomeruli and tubules
atrophied. Bronchitis, pneumonia, hepatic cirrhosis, heart enlarged,
fatty, dilated, insufficient valves. Prognosis unfavorable. Treatment:
gentle exercise, warmth, succulent food, amylaceous, tonics, iron,
bitters, mineral acids, heart tonics, for polyuria bromides or
iodides, balsams, pilocarpin, fomentations or sinapisms to loins.
Chronic nephritis has received little attention in the lower animals for
various reasons. The lower animals largely escape the causative factors
of alcoholism and chronic lead and copper poisoning, and when suffering
from any chronic affection that disqualifies the animal for use and
renders it anæmic and emaciated it is naturally sacrificed to save the
cost of maintenance. In spite of this a considerable number of cases
have been recorded in horses, and cattle and especially in dogs and
cats.
_Causes._ Cases of acute nephritis sometimes improve and give promise of
recovery without completing the work of convalescence. Trasbot notes
such cases in the dog, and Dickinson in the ox. Alcoholic nephritis and
degenerations are to be sought for especially in cattle kept on
distillery and brewery dregs. Lead taken in small quantities in soft
water that has run through lead pipes or stood in leaden cisterns
produces in cows and other animals chronic affections of the kidney.
Ellenberger and Hofmeister have produced the disease experimentally with
lead and copper respectively.
Microbian invasions of the kidney that advance slowly like glanders and
tubercle are further causes of chronic nephritis. Other secondary
microbian infections of the kidney are complications of infectious
diseases in other parts, including abscess, pyæmia, septicæmia,
ulcerative endocarditis of the left heart, bronchitis, pneumonia
(Fröhner), and of others less directly in the line of the circulation,
as omphalitis, uterine phlebitis (Lustig), abscess of the nasal sinuses,
bones, and fistulæ (Trasbot).
In other cases the nephritis is evidently a result of the irritation
caused by toxins in process of elimination by the kidneys, as there is
no evidence of a nephritic infection.
In some instances minute emboli originating in the lungs or heart,
become the starting point of the nephritis, which slowly extends by
reason of infection or low condition and special susceptibility. Disease
of the aorta or renal artery may lead to this condition as noticed by
Cadeac and Lustig. Cadeac has also noticed its association with aneurism
of the mesenteric arteries so that the strongylus (sclerostoma) armatus
may be considered as a factor. Again in old horses and dogs it has been
associated with atheroma of the aorta and renal vessels (Trasbot).
Overfeeding is not without its influence, especially when on animal
food, which charges the kidneys with excreting an excess of the
irritating urea and uric acid, and this is one reason why it is far more
frequent in house dogs than in other domestic animals. When the meat is
already decomposing and putrid there is the added evil of a quantity of
toxins and even of microbes to be eliminated from the system by the much
abused kidneys. Add to these that the dog’s urine is even in the normal
condition more dense and contains more irritating ingredients than that
of herbivora, and that owing to the slight activity of his perspiratory
apparatus he can obtain less relief from the skin, and we find a
substantial ground for the prevalence of chronic nephritis in this
animal.
Disease of the valves of the right heart or dilatation with
insufficiency of the auriculo-ventricular valves is a potent cause of
nephritis, the reflux of blood into the veins and the increased venous
tension, speedily producing passive congestion and a slow type of
inflammation in the kidney. This factor is especially liable to operate
in dogs, which are particularly obnoxious to rheumatism and valvular
ulceration, and are very subject to nervous cardiac disorders; in horses
that have contracted heaves; and in beef breeds of cattle which suffer
from fatty degeneration of the heart with dilatation.
The influence of calculi must not be overlooked, whether they are lodged
in the pelvis, the chalices, or the uriniferous tubules. Their tendency
is to induce local irritation and exudation, with fibroid degeneration
and thickening of the walls of the tubules or pelvis and of the adjacent
tissue.
When to one or more of the above conditions there are added overfeeding
or what is worse a low condition from starvation or unwholesome food
(permeated by bacteria or cryptogams or containing vegetable acids), and
when to crown all there are frequent exposures to cold or wet, we have a
vicious combination especially conducive to kidney trouble.
Habitual retention of urine in mares in harness, in house dogs, or in
horses in railway cars, and violent exertion, or sprains of the back are
among the remaining accessory causes.
_Symptoms._ These are often slight or obscure, so that not only owners
and attendants but even veterinarians are liable to overlook them. Loss
of flesh, flabbiness of the muscles and a lack of spirit and energy are
among the first symptoms. The _horse_ appears stiff, especially in his
loins and hind limbs, and fails to advance the hind feet as far under
the belly as formerly, and straddles more. When put to work he is early
fatigued and appears unfit for sustained exertion. His movements are
slow and if urged to a trot he may even groan with every step and
quickly settles back to his sluggish pace. If turned sharply round on
himself he does so with difficulty and often groans. When he is mounted
or when the loins are pinched he may droop to excess. If you come on him
lying down, and urge him to rise he may rise on his fore limbs and sit
on his haunches until urged before he makes any attempt to raise himself
on his hind. The _dog_ may spend most of his time in the kennel, and
show little disposition to run, play or hunt. On the contrary the owner
may have to call him several times before he will come out and then he
moves listlessly, wearily and even weakly.
In all animals the appetite is poor or capricious, and the patient
gradually loses condition, at first slowly and later, after a few weeks
or months, more rapidly. The advance of anæmia is also steadily
progressive.
Dropsical effusion is not uncommon. It is often prominent in the horse
as stocked limbs, but may be absent for a length of time. In other
animals it is more likely to appear later in the disease and under the
chest or abdomen or in one of the internal serous cavities. Trasbot has
found it absent for months in the nephritic dog.
The exploration of the kidney through the flaccid abdominal walls in
small animals, and through the rectum in small horses and cattle, may
reveal renal tenderness and even swelling. If there is a tendency to
frequent passage of urine in small quantities, or to straining without
micturition, the indication is of value.
There may be little or no fever, and, when left at rest, little evidence
of discomfort.
Any indication of urinary trouble, and especially with dropsy, weakness,
flabbiness and anæmia and a subnormal temperature, should lead to
examination of the urine, as a crucial test. A high density is good
ground for suspicion. But this is not constant. In advanced cases
(chronic interstitial nephritis, small white kidney, atrophic nephritis)
it may be 1015 to 1025, in exceptional advanced cases with polyuria, it
may be 1010, 1005, or even 1001. With such a condition, however, there
is great anæmia, pallor of the mucosæ, and prostration. Tested with
nitric acid and heat, the urine throws down an abundant precipitate of
albumen. Under the microscope it shows a profusion of granular,
degenerating epithelial cells, and casts of the uriniferous tubes.
_Progress._ The course of the disease is usually slow, extending over
several months, but with a tendency to constant advance. The thirst
increases and the urine increases in amount, clearness and levity. There
may supervene extreme sluggishness, dropsies, anæmia, and weakness,
irritability of the heart, and palpitations on slight exertion. So long
as the heart’s action is strong, elimination may be maintained and life
prolonged for months (in cow, Dickinson), or years (Friedberger and
Fröhner). When the heart’s action becomes weak, elimination is rendered
imperfect and the animal shows catarrh of the lungs or bowels (common in
dogs), local inflammation of the lungs, pleura or pericardium, or
œdemas, or hæmorrhages. The toxic effect on the nerve centres is shown
by stupor or lethargy, or vertigo. When an abscess forms it is
associated with a temporary rise of temperature (Trasbot). The patient
may die in convulsions, in a state of coma, or by gradually advancing
debility and failure of the heart.
_Lesions._ In cases of comparatively =short standing= the kidney is
usually of full size, or somewhat enlarged, with firmly adherent capsule
and rough or even nodular surface. The surface of the cortex may be red
or grayish or parti-colored, pink and gray. The cortical portion is firm
and it may even be attenuated somewhat, while the medullary portion,
naturally lighter, has often grayish streaks converging toward the
hilus. When the gray streaks are scraped with the knife a serous fluid,
mixed with fatty granules or globules, is obtained. The glomeruli may be
still about the normal size with some increase of the epithelial tuft
cells. The tubules contain casts (colloid, hyaline, granular), and their
epithelium normally columnar, are flattened down to cubes and are
swollen, granular or fatty.
In cases of =older standing= the connective tissue has usually undergone
a marked increase. The capsule is thick, dense and adherent. The
cortical substance is shrunken with a great increase of the fibrous
elements, and the same holds true of the medullary portion. In
consequence of this, even in the cortical substance the white or gray
color predominates. The parenchymatous tissue (glomeruli, tubules) have
greatly shrunken. In connection with the contraction of the forming
fibrous hyperplasia, there is a general shrinkage of the kidney in size,
it may be to one-half its original volume. Trasbot reports a case of
nephritis, of 8 months standing, in the dog, with a kidney half the
normal size. In the end the parenchyma may have practically disappeared,
and the kidney may have shrunken to a small, firm, white, fibrous mass.
Abscess of the kidney is exceptionally met with (Laurent, Lafosse).
_Lesions of distant organs_ are not uncommon. Bronchitis, pneumonia,
pleurisy, insufficiency of the tricuspid or mitral valves, dilated
heart, hypertrophied or fatty heart, congested or fibroid liver,
arteritis, and dropsies are among such morbid conditions.
_Prognosis._ This is almost always unfavorable. Death may be delayed for
months or years, and partial transient recoveries may take place but a
restoration to normal structure and function is not to be looked for.
_Treatment._ This cannot be expected to be much more than palliative.
The avoidance of overwork, and of the exposure to cold and wet, and the
securing of a free action of the skin by warm buildings and clothing,
are essential. The diet should be easily digested and non-stimulating,
for _herbivora_ green food, carrots, roots, apples, silage, with a
moderate allowance of oats to counteract weakness and anæmia; and for
_carnivora_, milk, buttermilk, mush made of oat, wheat or barley meal,
with, if necessary, a slight allowance of tender raw meat. Tonics fill a
similar need. Iron and bitters may be combined. Or hydrochloric acid or
nitromuriatic acid with bitters (nux, calumba, salicin, quassia) may be
tried. These acids are especially valuable when the case has originated
in or is maintained by calculi, indigestion or hepatic disorder. When
the heart is defective in tone, it may be stimulated by small doses of
digitalis, strophanthus, sparteine, caffein, or nitro-glycerine, or to a
certain extent by strychnia or nux. These, however, must be used with
judgment, if it is found that they aggravate the case by increasing the
arterial tension. In those cases in which there is an excessive
secretion of watery urine, the possible source of this in musty aliment
should be avoided, and the flow checked by nux vomica, in moderate
doses, and bromide or iodide of potassium in full doses. When, on the
other hand, the urine becomes scanty and dense, the great danger of a
toxic action must be met by agents that favor excretion. Pure water at
will is perhaps the least objectionable of such agents, but potassium or
sodium acetate or citrate, or even sodium chloride, in weak solution,
may be given. In some cases benefit will come from a moderate use of the
balsam of copiaba, or the leaves of buchu, which may improve the tone of
the secretory elements. The most promptly effective of these agents is
pilocarpin (Friedberger and Fröhner), but it has the serious drawback of
inducing profuse and dangerous depletion and debility. Yet in careful
hands, and with good cardiac tone, it may often be used to advantage.
Fomentations over the loins, warm baths and mustard embrocations, may at
times be beneficial. Attempts have been made to check the hyperplasia by
the use of arsenic, mercury or the compounds of iodine, but their use in
such cases is based on theory rather than accomplished results.