DISEASES OF THE BONES AND JOINTS The so-called scrofulous diseases of the bones and joints most assuredly pertain to the class of tuberculosis and a discussion of them in these pages is only a concession made to the old term "scrofula," to which those diseases are supposed to belong.
The limited space which could be devoted in this manual to the subject of scrofula only permits a brief statement of the general path ology and symptomatology of the subject. For details we must refer the reader to the text books on surgery.
The tuberculous diseases of the bones nearly always appear as a secondary disease, originating through infection from some existing localized area. The structure of bone marrow is such that tubercle bacilli circulating in the blood are easily arrested, and these subse quently lead to the formation of tubercles in the bone marrow. The tuberculous granulation-tissue liquefies the bony structure, and may lead to necrosis, or to the formation of a sequestrum. It spreads centrif ugally, producing a state of caseation. This process may extend periph erally to the periosteum and cause a tuberculous periostitis. A cold abscess may now result, the process including the overlying soft parts. Fistulas may arise and discharge externally.
If the softening of the bone is accompanied by enough resistance on the part of the periosteum, then a peculiar spindle-shaped swelling results, particularly in the phalanges of the fingers which is known by the name of spina ventosa. Since the tuberculous affections are in clined to remain in the neighborhood of the articulations, the extension of the process to the joints is easily explained. Primary involvement of the joints is rare. In the joint there develops an exudate of a serous or even seropurulent nature. Gradually the synovial membrane changes to spongy granulation tissue, which, penetrating the cartilage, destroys it, and detaches it from the bone. By degrees the process spreads over the soft parts, they swell, become oedematous, the surface turning white and glossy, and the whole joint presents a spindle-shaped swelling known as tumor albus or white swelling.
Other diseases of the bones, spondylitis for example, are at present generally separated from scrofula and for that reason must he studied elsewhere.
The process in the localized bone diseases is extraordinarily slow and tedious. At first there are no symptoms, then from time to time mild pains, especially at night, are felt. Gradually these pains become more severe, function is disturbed in the beginning and finally is ren dered impossible. By this time objective changes are noticeable, such as have been described above.
prognosis of scrofula is, in general, favorable. The scrofulous phenomena themselves never result in death. They finally heal though they may frequently last for years without leaving any marked functional disturbances. Serious disturbances may how ever threaten the eyesight, as has been already explained.
But the prognosis assumes a different character when we consider the relation of scrofula to other tuberculous phenomena and to certain diseases. We must. accustom ourselves to regard the scrofulous indi vidual as infected with tuberculosis, in other words to have an infec tious disease; which for the time is quiescent and not dangerous, but is apt at any time to assume such a role under favorable conditions. Such favorable conditions are unhygenic surroundings and malnutri tion. A scrofulous child thus exposed is in great danger.
Instead of suffering from a comparatively harmless form of scrofula it may acquire a severe tuberculous affection jeopardizing permanently its health and life. In many cases re-infection may occur if the child is associated with a phthisical subject.
There is hardly any doubt that the form of tuberculosis, whose symptoms are grouped under the name of scrofula, creates in the organ ism a certain sensitiveness and susceptibility to re-infection. Our present biological knowledge teaches us that there is a hypersensi tiveness to the virus in question, which can be distinctly proven by the reaction produced by the smallest doses of tuberculin.