Localized lymphangitis is frequently set up by specific kinds of irritation. The adenitis and periglandular inflammations in cases of scarlet fever and diphtheria are familiar illustrations. The indurated glands in syphilis and suppurating buboes in chancroid exhibit the different effects of the virus of these forms of disease. The lymphatics of the solid viscera are often inflamed when the organ is the seat of disease. Pelvic cellulitis, if not in itself a lymphangitis, may be the starting-point of a severe and extensive inflammation of the absorbents, occasionally involving both the superficial and deep-seated vessels along one or both thighs.
Age and constitution are recognized factors. Lymphangitis is more frequent in the young, and is much more easily excited in the strumous and persons in a low state of health. Unhygienic conditions predispose to its development.
Lymphangitis may also find its cause in excessive exercise of function, paralysis of vessels, mechanical obstruction to the lymph-stream, lodgment of particles of cancerous or tuberculous matter in the vessels, compression from cicatrices, indurated connective tissue, tumors, diseased glands, stasis in large veins, and regurgitant heart affections.
SYMPTOMATOLOGY.—Reticular lymphangitis is characterized by rapidly-increasing localized redness, attended with a burning, throbbing pain, and usually quickly implicates the skin and its capillaries. Oedema to a greater or less extent may soon ensue, which, when present, increases the pain. Fever may or may not be present, depending in some measure upon the extent, intensity, and cause of the inflammation and upon individual peculiarities. Erythema usually represents a reticular lymphangitis with hyperæmia of the skin and its capillaries, and erythema nodosum is the same associated with lymphatic oedema. Any trivial injury may induce this form of inflammation, such as a prick or the sting of an insect, which in extent, duration, and intensity will vary with the cause, nature of the poison introduced, location, and susceptibility of the sufferer.
Tubular lymphangitis is usually a much more serious form of the disease. When the vessels of the superficial set are involved, wavy or straight irregularly reddened lines are seen along the course of the vessels, extending from the point of beginning to a single gland or ganglion, which is usually tender and enlarged. These lines feel like hard, knotted cords. The inflammation may be limited by the first tier of glands, or it may extend to one or more distant ganglia. From the inflamed gland the disease may be conveyed along the connecting branches of the deeper set of vessels, and both sets may become involved. The inflammation may also extend through the intervening tissues from the superficial to the deeper-seated vessels. When both sets are involved, the disease assumes a graver form and the symptoms are aggravated. The pain becomes more acute, and the swelling is greatly increased and more diffused. Fever may or may not be present, and is usually moderate when the inflammation is confined to the superficial vessels, but when the deeper set is implicated it often commences with a rigor and is usually considerable. When the deeper set is alone affected the red wavy, knotted lines cannot be seen, but may, unless the oedema is great, be felt. The parts are swelled, indurated, and stiffened, due in the acute stage to increased saturation of the tissues, and in the chronic stage to hypertrophy of the connective tissue. When the oedema is great the covering integument presents a glossy, shining appearance.
PATHOLOGY AND MORBID ANATOMY.—In lymphangitis the adventitia of the vessels and surrounding connective tissue are chiefly affected. The external coat is thickened, injected, and infiltrated with cells. The intima becomes opaque and is stripped of its endothelium. The lymph coagulates in the interior of inflamed vessels and blocks up the channel. These thrombi may become organized and permanently obliterate the lumen of the vessel, or they may liquefy or suppurate. Their products may enter the circulation and cause septicæmia or pyæmia. In a few instances the clots have undergone calcareous degeneration. In some instances coagula are found independently of any disease of the coats of the vessels. In such cases the coagulation has been caused by the entrance of some foreign material into the lymph-stream. The thickening and relaxation of the coats of the vessels lead to dilatation, and consequently to slowing of the current and stasis of lymph. From this may result the serious consequences of an extensive lymphangiectasia, which may involve either or both the superficial and deeper vessels of a large area or an entire extremity. In such cases enormous development of the adipose tissue usually takes place, not infrequently associated with rupture of the dilated radicals and exhaustive periodic discharges of lymph. In most of the cases of lymphangiectasia and lymphorrhagia the fluid, which either accumulates in the affected area or is discharged through the ruptured orifices, presents the physical characteristics and appearance of chyle, due to the quantity of fat it contains. In some cases the fluid at first discharged is serous, and gradually changes, as the flow continues, to a chylous or milk-like fluid. In these cases there is also a tendency to frequently-recurring attacks of an erysipelatous or elephantoid inflammation. This predisposition is traceable to the structural changes produced by the previous inflammation, traumatism, or thrombosis. Inflammation and lymph-thrombosis are the pathological processes which usually cause circumscribed narrowing or complete occlusion of lymph-channels; and within the area from which the narrowed or occluded vessels originate there is lymph-stasis, dilatation of trunkal vessels, and oedema of the tissues. Lymphangitis may also cause adhesion of the internal surfaces of the vessel, fibroid transformation or calcification of their coats, and suppuration.
The alterations which take place in the lymph consist chiefly of an increased proportion of fibrin, the addition of numerous cell-elements, not unlike endothelial cells, white and occasionally red blood-corpuscles, lymphoid cells, granular matter, and a varying quantity of albumen and fat, which in a measure must owe their presence to pathological processes affecting the intima and to transformation of the inflammatory products.
All forms of inflammation of the lymphatic vessels exhibit a tendency to extend to the connective tissue. Cellulitis is almost a constant accompaniment of lymphangitis. In other cases the inflammation and consequent thrombosis and obstruction of the lymph-stream produce oedema and saturation of the tissues. Hyperplasia and sclerosis of the connective tissue follow.
Adenitis is characterized by swelling, congestion, and hardness. If resolution takes place, as is usual in all forms of simple lymphangitis, the gland or ganglion will be restored to its normal condition, though not infrequently some enlargement and firmness will remain for a considerable time, which favor recurrences from very trivial causes. It often happens, however, that structural changes occur. Exudation and suppuration may take place. Suppuration begins in the centre, and sooner or later the whole gland-structure is converted into a pus-cavity. Buboes are usually associated with periglandular abscesses. In fact, the latter are very frequently present when the glands do not suppurate, but have assumed a condition of chronic or subacute inflammation, which subsides very slowly and is subject to recurring acute exacerbations from some continuous or repeated irritation. Glands may be devastated or rendered wholly or partially impermeable, thus forming permanent and irremediable obstacles to the lymph-stream. Inflamed and swollen glands are not necessarily impermeable, but the flow of the lymph through them is undoubtedly impeded. The subacute or chronically inflamed glands may become adherent to and imbedded in a mass of indurated connective tissue, and may finally undergo calcareous or caseous degeneration.
Lymphangitis sometimes extends by contiguity of tissue to the synovial membrane of joints, most frequently the knee-joint. So likewise may synovitis and other joint affections set up a lymphangitis. In either case the tendency to suppuration is imminent.