Infection varied, through wounds, autogenous. Simple irritation,
simple lymphangitis. Causes, sun’s rays, bruises, other injuries,
lymph coagulation from heat, cold, chemical irritants, and coagulants.
Germs in blood act on debilitated tissues, lymphatic constitutions,
anæmic, overworked, or starved. Insect bites, claws, teeth of
carnivora, foul instruments, fingers or clothes. Bloodless wounds
dangerous. Distal parts of the limbs exposed. Fresh wound exposed,
granulating less so. Most microbes enter by the lymphatics. Symptoms,
extension from wound, swollen lymphatics, reticular lymphangitis,
tubular lymphangitis, farcy, tuberculous case, slough. Fever variable.
General infection. Joint infection. Chronic cases. Lesions. Diagnosis,
from phlebitis. Treatment, antiseptics, diet, eliminants,
antithermics, blisters, mercurial ointment, iodine, lancing, tonics,
massage, bandage.
Under this heading must be named not one specific disease but a group of
infections entering by the lymphatic vessels and developing inflammation
of their substance. They may be divided into two classes: those caused
by infection through external wounds and those in which the poison
already in the system becomes localized on a weak or exposed tissue.
A third class must be included, in which there is no recognizable poison
but simply a local irritation which leads to coagulation or other
alteration in the lymph, or disease of the lymphatic vessels.
This subject belongs rather to surgery than medicine but it seems
necessary to contrast it here with the plethoric form of equine
lymphangitis. Most of its forms pertain to infectious diseases and will
be treated in connection with these.
_Causes of Simple Lymphangitis._ Formerly many forms of lymphangitis
were ascribed to mere local irritation; a superficial form will occur
from exposure to the rays of the sun, and an inflammation attendant on a
bruise or other injury with unbroken skin, may cause local inflammation
of the lymph vessels and enlargement of the adjacent lymph glands. As we
have seen above coagulation of the lymph and fibrine embolism may induce
local inflammation in the walls, and this may occur in connection with
excessive heat or cold or the presence of chemical irritants and
coagulants. These cases are however rarely serious and the tendency
today is to trace nearly all cases to infection, from germs already
present in the lymph or blood, or introduced through a wound or sore.
The effect of germs already circulating was shown in the beautiful
demonstrations of Chauveau in regard to calves subjected to castration
by subcutaneous torsion (bistournage). In the healthy calf the simple
operation gave rise to little disturbance. The healthy calf injected
with septic liquids equally escaped visible trouble. But the calf
injected with septic liquids and then subjected to bistournage had a
fatal infecting inflammation. There is a strong presumption that, in
lymphangitis, starting from an injury with no external sore, the germs
were already present in the blood or tissues but were unable to do any
serious damage until the injured and weakened part or organ offered an
area of lessened resistance to their colonization. Following the same
line of thought it has been noticed that animals of a coarse texture,
and lymphatic constitution (heavy draft horses and animals raised for
the butcher), and such as are debilitated by anæmia, overwork, or poor
and insufficient nourishment are above all liable to be attacked by
lymphangitis.
The insertion of the septic poison may take place through the bites of
insects, the claws, or teeth of carnivora that have been devouring
tainted or infecting meat, through the lancet or operating instrument of
the surgeon, by his fingers or the dust from his hair or clothes. The
wound is perhaps more likely to be infecting if it leads to no effusion
of blood, but affects only the thickness of the epidermis, as there is
less chance for the washing out of germs by the flowing blood, and there
is less care to employ antiseptics. Wounds in the feet and lower parts
of the limbs are specially liable to infection by reason of their
frequent contact with manure and decomposing organic matter in the soil.
A fresh wound, in which the lymph spaces are exposed, is somewhat more
open to infection than one that has advanced to the stage of
granulation, the layer of unorganized lymph and cells acting as a slight
barrier to the passage of the microbes.
Nearly all microbian diseases make their inroad by way of the
lymphatics, where the sparse cells fail to establish as active
phagocytosis as do the numerous moving cells of the blood. Hence a
number of infectious maladies are primarily and pre-eminently diseases
of the lymphatics, as glanders, strangles, tuberculosis, cancer,
anthrax, swine-plague, etc.
_Symptoms._ The most common form is where lymphangitis extends from some
pre-existing wound—as pricked or suppurating foot, fistula of foot,
withers or poll, chafing of shoulder or back, cracked heels, boil,
sloughing bruise, etc. The swelling around the sore or injury involves
in fact the radical lymphatic plexus in the connective tissue (reticular
lymphangitis). When the swelling extends and becomes more tense, with
firm, painful sinuous cords running out of it in different directions,
and especially toward the nearest lymphatic glands, and when these
glands are slightly swollen and tender, tubular lymphangitis is
diagnosed. No more striking example can be found than in skin glanders
(farcy). The rigid cords extend from the side of the face, from the eye,
and nose down toward the submaxillary glands and with more or less
adjacent engorgement. Or on a hind limb, or some portion of the trunk, a
more or less turgid swelling with one or more firm nodes (farcy buds)
and painful, tortuous cords running towards the lymph glands is very
characteristic.
A tuberculous case may show an indolent, hard, comparatively insensible
cutaneous cord leading toward the jugular furrow, the prescapular,
precrural or inguinal glands, and at long intervals softening,
fluctuating, bursting and discharging a thick pus. In a carcinoma there
is the old, hard, nodular, and finally ulcerating swelling from which
the firm cords extend to the mass of steadily enlarging lymphatic
glands.
A simpler form is where a bruise by the harness causes a hard, thick,
slough, embracing the entire thickness of the skin, from which the firm
corded lymphatics extend in different directions. After the slow process
of detachment, the local lymphangitis usually subsides under simple
cooling or antiseptic treatment.
But the grade of such lymphangitis is as varied as the particular germ
or combination of germs present in the wound, and the susceptibility of
the animal attacked, and there will be high, moderate or no fever,
according to the severity of the case, and in some cases purely local
trouble and in others general infection with purulent or septic
localization in distant parts. There is always danger of extension to a
neighboring joint with destructive results.
A curious outbreak is described by Wiart as attacking nearly every horse
in the regiment that sustained a slight wound. A tubercle looking mass
formed in the depth of the wound was slow to heal, and the lymphatics
leading out from it became round, corded, turgid, and at long intervals
developed along their course fluctuating centres which, whether opened
spontaneously or by the lancet, showed the same indolent habit. A single
attack would last from two to six months, and the actual cautery had to
be used on the sores.
The _lesions_ are those already described in the last article for simple
lymphangitis. For infecting cases they are those of the particular
disease which may be present.
_Diagnosis._ The general diagnosis of lymphangitis is the distinction
from phlebitis. In phlebitis the vein is blocked and cannot be raised by
pressure on the side leading toward the heart; in lymphangitis it can be
so raised. The swelling and tenderness are both greater in lymphangitis.
The inflamed vein is more rectilinear, the lymph vessel somewhat
sinuous. If suppuration ensues it is more diffuse in lymphangitis; more
restricted and mixed with the elements of blood in phlebitis.
For identification of the particular forms of infecting lymphangitis,
the reference must be made to the individual infectious diseases.
_Treatment._ In general the treatment of lymphangitis is the antisepsis
of wounds. Further than this the treatment of each case is that of the
particular disease which it represents. For all cases alike it is
important to apply vigorous treatment early, so as to cut it short
before it can attain a dangerous extension.
For the simpler forms of lymphangitis the wound should first be
thoroughly cleansed and disinfected. Washing with soap suds, or
carbonate of soda will remove any greasy agent which would prevent a
thorough antisepsis. Then it may be washed with the antiseptic
lotion:—carbolic acid solution (1:20), or mercuric chloride solution
(1:500), or zinc chloride (1:400) or potassium permanganate (1:160). If
the infection has been introduced by a small or punctured wound, the
sting or bite of an insect, or the prick of a sharp instrument it should
be freely cauterized to its depth with lunar caustic incising it if need
be to reach the whole of the poison, and the surface afterward dressed
with antiseptics.
The diet should be light but nutritious and laxative, and the free
action of the bowels and kidneys should be maintained by salines. When
fever runs high give quinine, or salicylate of soda. When a large wound
has to be dressed it may be requisite to use a non-poisonous agent like
acetate of aluminium or boric acid to irrigate it thoroughly. In some
such cases packing the irrigated wound with iodoform gauze has often an
excellent effect.
When there is a firm inflamed cord, hot and painful, a fly blister along
its course followed by mercurial ointment often gives excellent results.
Or they may be repeatedly painted with tincture of iodine.
Foci of suppuration must be promptly opened and thoroughly and
persistently disinfected.
With suppuration in multiple abscesses or large open sores liberal
feeding must be enjoined and iron and other tonics should be resorted
to.
The persistent swelling of the part must be met by active rubbing or
kneading, by exercise and by uniform compression by a flannel or elastic
bandage.