A new approach to the pathogenesis of extrapulmonary tuberculosis

Certain observations which seem clearly to indicate that most spontaneous cold abscesses of the chest wall and many instances of Pott's disease are due to the transport of tubercle bacilli from the pleural spaces to the parasternal and the para-aortic lymph nodes respectively, and the subsequent breakdown of caseous foci in these nodes, are reviewed. Evidence is presented which suggests that the parasternal and para-aortic lymph nodes may, and probably should, be regarded as the regional lymph nodes of the pleural spaces. Reference is made to certain experiments which seem to indicate that the rate and/or the depth of respiration influence the speed with which, and the extent to which, particulate matter is transported from the pleural spaces to their regional lymph nodes. Certain experiments in which Mantoux negative guinea-pigs were injected intrapleurally with various doses of virulent tubercle bacilli are described. These experiments show that guinea-pigs injected intrapleurally with supposedly sublethal doses of tubercle bacilli commonly die within a few weeks from widely disseminated tuberculosis. Necropsy examination of these animals revealed pleural changes of a minor nature (a few tubercles and/or some delicate adhesions) and tubercles in the liver of all, and enlarged parasternal and para-aortic lymph nodes and tubercles in the lungs, spleen and kidneys of some. The findings in five subjects who typify persons with extrapulmonary tuberculosis seen by the present writer in recent years are presented in some detail. These five patients have at least one thing in common—namely, that they took more exercise during the acute phase of their pleuritic disease than is generally considered desirable for those known to have, or suspected of having, pleuritis of tuberculous etiology. The pathogenesis of extrapulmonary tuberculosis is discussed in the light of the foregoing and of a recent paper by Roper and Waring describing the results of a follow-up study of a series of cases of sero-fibrinous pleural effusion. The findings presented herein seem clearly to indicate: (1) that some forms of extrapulmonary tuberculosis—namely, spontaneous cold abscesses of the chest wall and in some instances paravertebral abscesses and Pott's disease—are due to the transport of tubercle bacilli from the pleural spaces to the parasternal and the para-aortic lymph nodes respectively, with subsequent breakdown of caseous foci in these nodes and extension of the tuberculous pro