Lymph vessels are divided in all wounds, and the lymph that escapes from them is added to any discharge that may be present. In injuries of larger trunks the lymph may escape in considerable quantity as a colourless, watery fluid—lymphorrhagia; and the opening through which it escapes is known as a lymphatic fistula. This has been observed chiefly after extensive operation for the removal of malignant glands in the groin where there already exists a considerable degree of obstruction to the lymph stream, and in such cases the lymph, including that which has accumulated in the vessels of the limb, may escape in such abundance as to soak through large dressings and delay healing. Ultimately new lymph channels are formed, so that at the end of from four to six weeks the discharge of lymph ceases and the wound heals.
Lymphatic Œdema.—When the lymphatic return from a limb has been seriously interfered with,—as, for example, when the axillary contents has been completely cleared out in operating for cancer of the breast,—a condition of lymphatic œdema may result, the arm becoming swollen, tight, and heavy.
Various degrees of the conditions are met with; in the severe forms, there is pain, as well as incapacity of the limb. As in ordinary œdema, the condition is relieved by elevation of the limb, but not nearly to the same degree; in time the tissues become so hard and tense as scarcely to pit on pressure; this is in part due to the formation of new connective tissue and hypertrophy of the skin; in advanced cases there is a gradual into one form of elephantiasis.
Handley has devised a method of treatment—lymphangioplasty—the object of which is to drain the lymph by embedding a number of silk threads in the subcutaneous cellular tissue.
Wounds of the Thoracic Duct.—The thoracic duct usually opens at the angle formed by the junction of the left internal jugular and subclavian veins, but it may open into either of these vessels by one or by several channels, or the duct may be double throughout its course. There is a smaller duct on the right side—the right lymphatic duct. The duct or ducts may be displaced by a tumour or a mass of enlarged glands, and may be accidentally wounded in dissections at the root of the neck; jets of milky fluid—chyle—may at once escape from it. The jets are rhythmical and coincide with expiration. The injury may, however, not be observed at the time of operation, but later through the dressings being soaked with chyle—chylorrhœa. If the wound involves the only existing main duct and all the chyle escapes, the patient suffers from intense thirst, emaciation, and weakness, and may die of inanition; but if, as is usually the case, only one of several collateral channels is implicated, the loss of chyle may be of little moment, as the discharge usually ceases. If the wound heals so that the chyle is prevented from escaping, a fluctuating swelling may form beneath the scar; in course of time it gradually disappears.
An attempt should be made to close the wound in the duct by means of a fine suture; failing this, the duct must be occluded by a ligature as if it were a bleeding artery. The tissues are then stitched over it and the skin wound accurately closed, so as to obtain primary union, firm pressure being applied by dressings and an elastic webbing bandage. Even if the main duct is obliterated, a collateral circulation is usually established. A wound of the right lymphatic duct is of less importance.
Subcutaneous rupture of the thoracic duct may result from a crush of the thorax. The chyle escapes and accumulates in the cellular tissue of the posterior mediastinum, behind the peritoneum, in the pleural cavity (chylo-thorax), or in the peritoneal cavity (chylous ascites). There are physical signs of fluid in one or other of these situations, but, as a rule, the nature of the lesion is only recognised when chyle is withdrawn by the exploring needle.