Definition. Symptoms and causes. Genera affected. Causes of plethora.
High feeding. Work followed by rest. Fever, hurried breathing, strong,
rapid pulse, anorexia, stiffness and swelling in a hind limb, inguinal
glands, connective tissue engorgement, corded lymphatics, suppuration
rare. Mild forms. Lesions, in lymphatic vessels and glands. Chronic
cases. Nature, plethoric, lymph excess, stasis, excess of cells and
fibrine, immunity of the fore limb. Season of prevalence. Climate.
Diagnosis, from farcy, erysipelas, etc. Treatment, exercise, friction,
resolvents, purgative, bleeding, diuretics, astringents, iodine,
pressure, diet. Prevention. Treatment of chronic cases.
_Definition._ Inflammation of the lymphatic vessels and glands of one
limb usually in connection with rest.
_Symptoms._ This affection is common in heavy draft horses of a
lymphatic temperament and kept on high feeding and at hard work. It
rarely develops however while the subject is kept at steady work. But
if, in the midst of such work, the horse is kept at rest in the stall
over one, two, or more days on the same generous diet, he is found
shivering violently, with rapid, labored, breathing, high pulse and
elevated temperature, symptoms which have been frequently mistaken for
those of pneumonia. There is complete anorexia, and often ardent thirst.
The patient is indisposed to move and if forced to it shows lameness in
one hind limb with an extraordinary abduction of the limb at each step,
and sometimes so severe as to prevent his putting his full weight upon
it. If an examination is now made high up in the groin close outside the
inguinal ring, the lymphatic glands will be found to be swollen, hot and
tender, so that under even moderate pressure the leg will be lifted and
abducted until the patient threatens to fall on the other side.
A little later the shivering may have given way to the hot stage, with
it may be general perspiration, and the swelling may have extended down
the course of the saphena vein and lymphatics, as a distinct ridge and
the lower part of the limb from the foot to the hock may be filled,
dropsical and hot. Unless checked the swelling goes on increasing till
the lower part of the limb is two or three times its natural thickness,
and the swelling has extended well up on the thigh. The swelling has a
soft œdematous feeling, easily receiving and retaining the imprint of
the finger and is not only hot, but excessively tender. From the margin
of the swelling, firm, tender, rounded cords are found to emerge passing
upward along the line of the saphena vein and its branches toward the
inguinal glands. These represent the swollen and gorged lymphatic
trunks, and may often be traced for some distance into the substance of
the general engorgement.
When the inflammation is violent, suppuration may ensue at one or
several centers, but more commonly the engorgement goes on increasing
and when the febrile attack has subsided the limb is left permanently
enlarged and correspondingly liable to a second attack.
Milder cases are met with which are perhaps even more misleading. There
may be little or no rise of temperature, loss of appetite or general
constitutional disturbance, but under some change of regimen and
particularly after one or two days of rest the subject becomes lame in
one hind limb, without any of the usual injuries to account for it.
Examination of the groin shows swelling and tenderness of the external
inguinal glands, with or without, a tender cord-like swelling running
down from them.
Between these two types may be found all grades of lymphatic
inflammation with a varied degree of attendant constitutional
disturbance.
_Lesions._ The coats of the inflamed lymphatic vessels are thickened by
exudate and the outer coat is the seat of ramified redness with minute
spots of blood extravasation. The inner coat is dull, opaque, or even
thickened. The vessel is dilated and its walls friable. The contained
lymph in the intervals between the valves has coagulated into a very
thin diffluent jelly-like clot, which in old standing cases may have
become granular. The connective tissue from which these vessels lead is
infiltrated with liquid and the lacunar spaces distended. Red patches
from blood extravasations are numerous. The external inguinal glands and
often the internal and sublumbar are swollen, congested, and the seat of
active cell hyperplasia. Abscesses are exceptionally seen.
In chronic cases the lymphatic vessels of the affected limb and
especially of the lower part which is permanently swollen, are
enormously increased in calibre (lymphangiectasis), and have their walls
correspondingly thickened. The connective tissue is the seat of
extensive fibrous hyperplasia, and its interstices are greatly enlarged.
_Causes._ _Nature._ This disease has not been sufficiently studied to
ascertain what toxic agents are produced in the plethoric condition,
under the torpid processes of nutrition and sanguification entailed by
absolute compulsory rest. A consideration, however, of the relations of
the lymph and lymph vessels and glands to other parts will in part
explain the pathology of the malady. The lymphatics take their origin in
the nuclear spaces of the various tissues, the anastomosing canals of
such pericellular spaces together with the latter forming the actual
radicles of this set of vessels. They receive, therefore, the surplus
plasma which is not used up by the tissue cells in performing their
trophic, secretory and other functions. This lymph carried on by the
_vis a tergo_, muscular compression and other movements, is delayed in
the adenoid tissue known as lymph nodes, and especially in the lymph
glands, in which the proliferation of lymph cells is mainly carried on.
Thus the lymph cells are very scarce in the lymph radicles of the
connective and other tissues, and are found in greater numbers after
passing through the lymph nodes, and in still greater after passing
through the lymph glands. But the increase of cells is also in inverse
ratio with the rapidity of the circulation of the lymph. When this is
rapid the cells are hurried on and there is little time for their
reproduction. When slow on the other hand, there is time for cell growth
and division in the glandular detention cavities, and the ratio of cells
to the plasma is materially increased. Consider next that the
multiplicity of cells determines an increase of the fibrine factors, so
that the more cells the lymph contains there is the more material for
fibrine (Landois), and we have one good reason why under enforced rest
the overcharged and congested gland may become the seat of fibrinous
coagula or lymphatic embolism. Any overdistension, toxic element, or
other cause of disturbance, which deranges the functions of the cell or
causes its rapid multiplication by division—as in inflammation—at once
sets free the fibrine ferment and determines the coagulation. In the
disease before us we have the overfeeding of an animal having a strong
digestion, we have an absolute compulsory inactivity, with a suspension
to a large extent of the functions of nutrition, sanguification,
secretion, and elimination; we have in consequence an increase of the
blood pressure, and of the solids of the blood and of the plasma of the
lymph; we have a suspension of the great motor force of lymph
circulation, namely, the muscular contraction, and we have the
consequent tardy movement of the lymph, the great increase of
lymphocytes, and the distension and engorgement of the lymph glands. As
soon as this has reached a certain stage the congestion and incipient
inflammation of the gland determines the precipitation of fibrine, the
obstruction of the gland, and of the entire circulation of lymph in the
lower part of the limb. The fever, the local swelling, and the
subsequent steps follow as a matter of course. This view is sustained by
the fact that incipient cases can be cured by muscular movement alone.
The rarity of the disease in the fore limb may be ascribed to the
greater force of the _vis a tergo_, the lesser height of the lymph
column, and the stronger action of the aspiratory power of the chest on
the lymphatic vessels.
In addition to the causes mentioned above must be noted the following:
The disease is an affection of heavy draft horses, in which the tissues
are more lax, and the lymph plexus in the connective tissue of the hind
limb is much more abundant. It is common in the heavy English, Scotch
and Belgian draft horses, and rare in the English racer, the American
trotter, and in the average light American horse. The malady is most
frequent in spring and autumn, when the work is hardest and the feeding
most abundant. It rarely attacks the horse in steady work, but appears
after an idle Sunday spent in the stable (Monday morning disease), or
after one or more days of compulsory idleness from heavy rains or other
cause. The damp climate of western Europe has probably an exciting
influence, as it has in producing the lymphatic constitution. In the
same line of thought Zundel says that many cold weather attacks would be
prevented by clipping off the heavy coat which keeps the entire system
relaxed. In some cases a sudden change of food, and in others musty oats
have been claimed as causes.
_Diagnosis._ Lymphangitis is distinguished from a simple dropsy of the
limb by the acute fever, the great local tenderness especially of the
inguinal glands, and by the tender corded lymphatics that enter these.
From cutaneous glanders (farcy) it is diagnosed by the more acute fever,
by the swelling of the inguinal glands in the early stage of the
disease, followed by the swelling of the lower limb, and by the absence
of the hard, comparatively insensible and prone to ulcerate, farcy bud.
Farcy buds usually appear on the pastern or fetlock, with more or less
swelling of the lower part of the limb, while the inguinal glands are as
yet normal in size and without tenderness. From erysipelas, with which
this has been confounded, it is distinguished, by the suddenness of the
onset, under the circumstances above described, by the high type of
fever, by absence of early cutaneous inflammation and the formation of
vesicles, and by the fact that lymphangitis commences in swelling of the
inguinal glands.
_Treatment._ In cases that are seen in the earliest stages, before the
leg has become badly swollen, recovery will usually take place under
active exertion continued for hours at a time. The pumping action inside
the hoof during exercise, and the alternate compression and relaxation
of the lymph vessels by the muscles, tend to establish a rapid current
of lymph, to break up coagula and to re-establish a healthy condition.
Friction from below upward on the lymphatic vessels and swollen limb
will greatly assist in this restoration. Different agents are employed,
such as camphorated spirits or oil, iodine, mercurial, and even
blistering ointments. These should not replace exercise when this is
possible.
When the fever has set in suddenly and runs very high, the abstraction
of four or five quarts of blood, and the administration of a purgative
(8 drs. aloes) will be in order. In cases occurring in the same stable
and in all other respects apparently identical, the subjects of
phlebotomy recovered without any permanent swelling of the limb, while
those that were not bled recovered with thickened limb.
In cases so advanced that the limb cannot be used, cold irrigation, with
friction, may be applied, and when the irrigation is intermitted one may
apply some astringent (vinegar, alum, lead acetate), or an iodine lotion
followed by an evenly applied bandage.
The purgative should be followed by full doses of diuretics (nitre,
bicarbonate of potash or soda, colchicum, iodide of potassium) until
fever and local inflammation have subsided.
As soon as the patient can use the limb, walking exercise should be kept
up for several hours forenoon and afternoon.
Throughout the disease the food should be of a light and non-stimulating
variety. When appetite returns give at first wheat bran, or roots, or
sweet grass in small amount, and do not return to a grain diet until
fully recovered and ready to go to work.
After one attack there is always an increased liability to a second, and
great care should be taken to give the subject daily exercise, or where
this is impossible, to reduce the feed, give a dose of saltpeter, and
turn into a yard or roomy loose box on the idle day.
In chronic thickening of the limb, an evenly applied elastic bandage,
extending from the hoof up, regular feeding and exercise, washing daily
with a weak iodine lotion, and the internal use of iodide of potassium
and other diuretics, with bitters and even iron tonics may be used.