Scrofula And Struma

These terms are used to designate conditions of the lymphatic glands, which are now generally recognized as tubercular. They will be described in their proper places. The terms have been somewhat indefinitely extended so as to include affections of joints, bones, skin, and other structures, but such affections are nearly all really tubercular.

Local Tuberculosis

We have already seen that tuberculosis is always, to begin with, a local affection, due to the implantation of bacilli in the living tissue, and it may be added that, even when it becomes generalized, the secondary lesions are due to the multiplication of bacilli transplanted from the primary seat, the growth of the microbe occurring not in the blood but in the local seat. Hence the description already given applies to the local process however originating.

The bacillus finds access to the body by various channels. The most common seats of tuberculosis are in direct communication with the surfaces of the body. The commonest seat of all is the Lungs, and entrance is here obtained with the inspired air. Next to the lungs the Lymphatic glands are most frequently affected, and in the case of children they are perhaps more frequently the seat of tuberculosis than the lungs. The lymphatic glands which are attacked are in communication either with the skin or a mucous membrane, and there are frequently catarrhs or other forms of inflammation in the tissue with which the affected glands are related. The bacilli may, however, find their way from surfaces which are unaltered. The glands most frequently affected are those of the neck, communicating with the mouth; of the mesentery, communicating with the intestines; and of the bronchi, communicating with the lungs. The skin may be directly attacked by tuberculosis, the resulting conditions being described as Lupus and Scrofuloderma.

While these more direct modes of entrance obtain in the majority of cases, there remain a large number in which the access is more circuitous. In some of these the tuberculosis is due to a secondary extension from a tubercular lymphatic gland. It is thus that many cases of tuberculosis of Serous membranes arise. But in a considerable number of cases, the bacilli can only have found access by the blood. The blood is not infrequently the vehicle by which small solid particles are conveyed, and we may suppose that a few bacilli accidentally present may be deposited in the tissues, and, in the case of a susceptible organ, may multiply and produce a tuberculosis. This applies to tuberculosis of the Bones, which is very frequent in children, and which often begins in the vertebrae, or in the cancellous tissue at the extremities of the long bones. The Brain is also liable to primary tuberculosis, especially in children. Tuberculosis of the Urino-genital system begins very frequently in the testicle, and the bacilli are carried thither by the blood.

Extension Of Local Tuberculosis

A tuberculosis once established in a locality presents usually a tendency to indefinite extension. Tuberculosis is generally a slow process, and the extension is also chronic. The extension is to the immediately neighbouring parts, by direct infiltration, or, more commonly, by the lymphatics or along surfaces and canals. The process of extension is usually stopped by the intervention of a membrane, as the bacilli seem not to be possessed of the power of penetrating membranes unless there is first a necrosis of them. Thus, tuberculosis of lymphatic glands does not pass through the capsule unless the latter have been perforated by necrosis; and tuberculosis of the lungs rarely extends to the pleura unless there be actual perforation of that membrane.

Extension by the lymphatics is very frequent and characteristic. Tubercles often form in the course of the lymphatic vessels connected with tubercular organs, as well as in the lymphatic glands. In phthisis pulmonalis, for example, there are tubercles in the substance of the lung seated in the lymphatic vessels, while the bronchial glands are also the seat of tuberculosis.

The extension along surfaces and canals is exemplified chiefly in serous and mucous membranes. A tuberculosis occurring in the pleura, pericardium, or peritoneum extends over the entire surface of these membranes. Tuberculosis, in communication with mucous canals, frequently travels considerable distances, involving the surface more or less continuously, but penetrating deeply to a very slight extent. Thus, tuberculosis of the lungs is frequently associated with tuberculosis of the bronchial mucous membrane, of the mucous membrane of the trachea and larynx, and of the intestine (from swallowing the expectoration). Again, tuberculosis of the genitourinary organs frequently begins in the testicle. From this it may extend the whole length of the vas deferens to the vesiculse seminales and urinary bladder, and sometimes up the ureter to the kidney.

It may here be remarked that in artificial cultures, the tubercle-bacillus grows on the surface of the medium, and does not penetrate into its substance. (See section on Bacteriology).

While tuberculosis does not readily penetrate deeply, still in vascular organs a few bacilli will occasionally reach the blood, passing either directly into the vessels of the part, or indirectly by the lymphatics. These may settle in predisposed situations, and give rise to secondary tubercular lesions in several different centres. This condition has been called by Weigert "chronic general tuberculosis." When a few bacilli, thus at intervals, find entrance to the blood, the lesions will usually be comparatively few. These secondary lesions run a chronic course, and may sometimes rival the primary tuberculosis in size and effect on the body. There may thus be a number of considerable tubercular lesions in different organs, and the case frequently looks like one in which several local tuberculoses are simultaneously present. This form of disease is most frequently seen in children, whose tissues seem more susceptible to the tubercle bacilli in smaller numbers than those of adults. In them we may find tubercular masses simultaneously in lungs, kidneys, brain, etc.