The characteristic morbid lesion in this disease is the degeneration of
the liver cells, loss of their protoplasm and nuclei and of their normal
functions. It may be circumscribed to limited areas, or may affect the
liver, generally. As the hepatic functions, are so intimately related to
those of the bowels and kidney, the affection is usually accompanied by
inflammations of these organs as well.
_Causes in horses._ The same general causes which produce congestion,
may also determine the further morbid stage of inflammation. Cadeac
mentions a case which developed in a horse kept alone and idle in the
stable. He makes no mention of condition, food, cleanliness nor
ventilation. Haubner and Franzen have traced it to a diet of malt or of
hay harvested from inundated meadows. Zundel records a case following
exposure to extreme cold. More commonly the disease is secondary to the
overtaxing of the liver, by heavy feeding in warm moist climates, or in
hæmoglobinæmia, or to the arrest of the micro-organisms of the food, or
of infectious diseases.
_Causes in Cattle._ These suffer rarely, but from essentially the same
conditions. It has followed aphthous fever (Eletti), and arisen under a
forcing ration, in hot weather (Callot, Cruzel), or under overwork
(Cruzel).
_Causes in Dogs._ Most cases result from infection by way of the stomach
and intestines, or by the transfer to the liver of the ptomaines and
toxins of such infections. It is thus related in its origin to catarrhal
jaundice and hyperæmia.
_Lesions._ In the earliest stage with albuminoid exudation into its
substance the liver may be greatly enlarged, its sharp edges rounded,
and its consistency softened. After a week’s illness atrophy may have
set in and the organ appears shrunken and of ocherous yellow. In the
early stages there may be sanguineous engorgement, the cut surface may
bleed freely, and small extravasations may show throughout the liver
substance, later the clay yellow hue, the granular aspect and the
absence of blood on the cut surface are characteristic. The margins of
the adjacent acini are indefinite or lost, and under the microscope the
hepatic cells are charged with granules (albuminoid, fatty and
pigmentary), while the nuclei are no longer demonstrable.
In _cattle_ the liver may be double the normal size and at first of a
deep purple red, which may change later to the earthy yellow.
In _dogs_ the liver is tumid and yellow, and marked by small pea-like
centres of softening. There is marked softening and the microscope
reveals the characteristic degeneration of the hepatic cells.
_Symptoms in the Horse._ These resemble those of congestion rendered
more intense and therefore somewhat less obscure. The attack is usually
sudden, there may be rigor followed by hyperthermia, dullness, pendent
head, drooping eyelids, injected conjunctiva with a yellowish tinge,
unsteady gait and slight indications of colic. There is anorexia,
partial suppression of urine, and what is passed is thick, glairy and
brownish red, fæces are passed with pain, and groaning, probably from
compression of the liver, the heart beats violently, while the pulse is
small, breathing accelerated and perspiration abundant. The temperature
rises (101° to 106°) and remains high throughout unless lowered through
biliary intoxication. Percussion over the liver and especially on the
right side shows increased area of dullness and marked tenderness. On
the second or third day the icterus usually increases, and a slight
fœtid diarrhœa may set in with marked fœtor of the pale or colorless
discharges. The jaundice is not, however, a criterion of the danger, as
it may become less marked or entirely disappear because of the extensive
degeneration of the hepatic cells and the arrest of the formation of
bile.
_Diagnosis in the horse._ The disease is recognized by the coincidence
of fever, with great depression, icterus, painful defecation,
constipation followed by a fœtid diarrhœa with lack of color in the
stools and by increased area of dullness and tenderness in the region of
the liver and especially on the right side. From influenza which it
resembles in many respects, it is distinguished by the absence of watery
discharge from the eyes, and by the entire absence of all indication of
contagion. The cases occur one at a time.
_Prognosis in the horse._ The disease is exceedingly fatal. When the
kidneys remain active, the poisons are eliminated and there may be hope
of recovery, but when urine is suppressed an early death by poisoning is
to be expected.
_Treatment in the horse._ A most important indication is to secure
depletion from the portal system. Calomel 1 dr., aloes 4 drs., ipecacuan
1 dr. may be given in bolus, and followed by small daily doses of
sulphate and nitrate of soda with bitters, with or without the
ipecacuan. Action on the kidneys is essential to secure elimination of
the poisons which threaten a fatal poisoning if retained. To favor the
same action fomentations may be applied to the loins. The frequent
presence of pathogenic microörganisms either in the bowels or liver
suggests the use of germicides (salol, salicylic acid, salicylate of
soda, naphthalin, naphthol, beta-naphthol, etc.) as in catarrhal
jaundice. Sinapisms or blisters applied to the right side of the chest
and over the short ribs may be useful, and after the subsidence of the
more violent symptoms, dilute mineral acids and especially
nitro-muriatic acid may be resorted to in combination with diuretics and
bitters.
When appetite returns succulent, laxative, non-stimulating food in small
quantity should be given. Wheat bran mashes, carrots, turnips, potatoes,
apples, fresh grass, ensilage may be adduced as examples. Throughout the
disease the ingestion of an abundance of pure water should be
encouraged.
_Symptoms in the ox._ These may appear more tardily than in the horse,
loss of appetite, staring coat, dullness, pendent head and ears,
unsteady movements, rigors, drivelling of saliva from the mouth and
grinding the teeth are usually noted. To these are added the more
diagnostic symptoms of slight (or severe) jaundice, constipation
followed by a fœtid light colored diarrhœa, a strong disposition to
remain recumbent, marked suffering attendant on rising, arching of the
back when up, and tenderness on percussion over the right hypochondrium.
The temperature gradually rises, though more slowly than in the horse,
and may again descend under a profound poisoning.
_Course._ The disease reaches its acme in four to six days, and
generally has a fatal issue.
_Treatment_, is on the same lines as for the horse only as a purgative,
sulphate of soda may advantageously replace the aloes.
_Symptoms in the dog._ The symptoms are those of congestion in an
exaggerated form. There are muscular tremors, erection of the hair,
followed by rising temperature up to 105° or 106°, an icteric hue of the
mucosæ, the pulse is accelerated, strong, irregular, respiration rapid,
panting, fœtid breath, ventral decubitus, and prostration extreme.
Appetite is completely lost, the bowels become relaxed, the stools
fœtid, the right hypochondrium painful on pressure or percussion, and
the urine greatly reduced and icteric or suppressed. This feature of
urinary suppression, determines a rapid poisoning and death in two or
three days.
_Treatment_ must follow the same lines as in other animals, a purgative
of calomel and jalap, followed by diuretics, laxatives, derivatives, and
above all germicides. In case of survival mineral acids, aqua regia,
bitters, and a carefully regulated diet will be in order.