Causes: age, overfeeding, idleness, atony, retention of urine.
Lesions: kidney enlarged, pale yellow, capsule loose, cut surface
glistening unctuous, oil globules in scrapings, granules soluble in
ether. Symptoms: in idle, overfed, obese, improved meat producing
breeds, closely confined, starchy or saccharine food, fatty granules
in urine, finally dropsies, anæmia, debility, sluggishness. Prognosis
unfavorable in advanced stage. Treatment: butcher, restricted regimen,
open air exercise, nitrogenous diet, crossing, diuretic food or drugs,
oil of turpentine, balsam copiaba. Palliation only.
Fatty degeneration of the kidneys is by no means unknown in the domestic
animals. It has been observed in dogs and cats (Rogers, Goubaux,
Vulpain, Trasbot). In dogs it has been erroneously set down as a
characteristic lesion of rabies. Like fatty degeneration of other
organs, it is also met with in old and overfed individuals of meat
producing breeds of animals, in which the tendency to early maturity and
rapid and excessive fattening has been fostered from generation to
generation. In man small, granular, fatty kidney is a common result of
chronic parenchymatous nephritis, and often coincides with fatty liver.
Chronic poisoning by arsenic or phosphorus is another cause, as it is of
fatty degeneration in other organs.
Vulpain has attributed it to a lack of active exertion and of general
tone, associated with excessive amylaceous feeding, sluggish, shallow
breathing and tardy elimination. Goubaux and Trasbot attach great
importance to the compulsory retention of urine in house dogs, cats and
horses. The damming back of the urine in the convoluted tubes and
glomeruli, temporarily arrests secretion, and the inactive and
compressed cells tend at once to granular and fatty degeneration.
_Lesions._ The gland is sensibly increased in size, and pale, yellowish
or straw yellow. The capsule is easily detached from the cortical
substance, contrary to what is the case in chronic productive
inflammation. The cortical substance is increased in thickness, and
pale, the pallor being largely in ratio with the duration or extent of
the fatty degeneration. The cut surface may be glistening and unctuous
to the touch. It is softer than usual, rather friable, and if scraped,
furnishes a serous or grayish pulp in which oil globules are prominent
features, together with granular epithelium and free granules that
dissolve readily in ether. Tubules are varicose and unequal at different
parts. The medullary portion has undergone little change. It may be
paler at certain points, with some shrinking of its substance and
increase of firmness.
_Symptoms._ As a rule the disease occurs in pampered, overfed and obese
animals, and in those of the improved breeds which have great power of
digestion, assimilation and fattening. It is especially to be looked for
after close confinement on full, stimulating, amylaceous diet. Symptoms
are not usually recognized during life. There is, however, a lessening
of the urinary secretion, and, as the disease advances, albuminuria.
When examined microscopically this is found to contain characteristic
elements, such as granular epithelial cells, the granules soluble in
ether, oil globules, and at times crystals of cholesterine (Beale). A
diagnosis based on the mere presence of oil globules may, however, be
fallacious, as these may be present in animals that have just been
heavily fed on oleaginous food, and again the oil used to smear the
catheter may float in the urine and prove misleading. Under such
circumstances vaseline or glycerine may be substituted on the catheter.
Scriba induced fatty urine by injecting fat or oil emulsion into the
blood, and Chabrie by ligating the large intestine. Trasbot says that
cylindroid casts may be present. As in other grave kidney affections,
dropsies supervene as the disease advances. These may show in the limbs,
in the abdomen, or in other serous cavities. A steadily advancing anæmia
with pallor of the mucosæ, listlessness, weakness, debility and
sluggishness are to be noted.
_Prognosis._ Since the disease is rarely diagnosed until it has reached
an advanced stage, it usually progresses steadily to a fatal issue. If,
however, it can be detected at an earlier stage, it may be palliated, or
held in abeyance, for a length of time varying with the extent of the
lesions. As it is very largely a disease of meat producing animals and
as the subject is at first in a condition of marked obesity, it can
usually be turned over to the butcher without material loss.
_Treatment._ If the disease has resulted from the inbred propensity to
fattening, the family that shows the disposition must be subjected to a
somewhat different regimen, open air exercise must take the place of
confinement in warm stables, a rather bare pasturage is valuable for
herbivora, and a restricted diet in which the oleaginous, saccharine,
and amylaceous constituents do not predominate, is strongly indicated.
Crossing with a strange male having many of the desirable qualities of
the herd, but which is more vigorous may be resorted to. When the
secretion of urine becomes scanty an abundance of pure water, or a diet
of succulent grass or roots or ensilage or even small doses of alkaline
diuretics may be resorted to. Any source of arsenic or phosphorus
poisoning should be cut off, and as an antidote to phosphorus, oil of
turpentine may be given in small doses. This agent may, indeed, replace
the alkalies as a diuretic, bringing in an element of tone for the
mucosa which is not to be despised. Or balsam of copaiba or buchu leaves
may be substituted.
When the small white kidney (granular, fatty) results from chronic
nephritis, the prevention and treatment would be as for that disease.
Little hope is to be entertained of entire restoration to health.