Text book of veterinary medicine, Volume 1 (of 5)

by James Law

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.