There
are two main varieties of tuberculous effusion :
(1)
occurring
as a late primary manifestation ;
(2)
due
to the presence sub-pleurally of post-primary foci.
Both groups sometimes
continue to a tuberculous empyema. The second occurs perhaps, more usually in
middle-aged or elderly subjects and is generally very chronic.
A late primary manifestation
Occurring as a late
manifestation of the primary infection, tuberculous effusion has its greatest
incidence between the ages of 15 and 25 years (Fig. 4).
Pleurisy
as an allergic phenomenon.—The view that the outpouring of
fluid represents an allergic phenomenon is maintained by Wallgren (1930) and
Rich (1946). An individual, having recently experienced his primary infection
with tubercle bacilli, is in a highly sensitive state, and the fluid appears in
response to the irritation of a sub-pleural primary focus at a certain stage of
its development, with the discharge of tubercle bacilli or tuberculo-protein
into the pleural space. The source of bacilli may also be tuberculous
tracheo-bronchial adenitis (Erwin, 1944). The degree of hypersensitivity
developed varies with the constitution of the individual patient. The effusion
may be of sudden onset or it may develop insidiously. It may be associated with
acute symptoms or it may be a casual discovery. The latter fact suggests that
certain individuals pass through an effusion of limited extent without its ever
coming to clinical recognition. Proof of this is difficult and an exact
expression of its frequency equally so. Some idea may be obtained from figures
supplied by Brooks. Of some 420,000 individuals between the ages of 15 and 75
years examined in the course of a fluorographic survey, 56 cases showed
radiographic evidence of recent primary tuberculosis with a symptomless pleural
effusion. The opportunity arose to observe 63 out of 259 individuals who showed
radiographic evidence of recent primary tuberculosis, and in 6 cases a pleural
effusion developed within 6 months.
Thompson
(1946) found that the effusion tended to form on the same side as the pulmonary
or glandular lesion. There is general agreement that the tuberculous primary
complex is right-sided more often than left-sided (Kayne, Pagel and
O'Shaughnessy, 1947) and in most cases the initial effusion is on the right
side.
Post-primary
effusion
Either
dry pleurisy or pleurisy with effusion may occur at any time during the
life-time of a consumptive patient. Dry pleurisy is often evanescent and marks
advance or extension of disease. Effusion may develop and, when it does so, the
accumulation of fluid is often gradual and insidious. The older the patient,
the more likely is the effusion to be loculated; the more gradual the
accumulation, the slower is the absorption, so that it is typical of
tuberculous effusion in middle-aged subjects to pursue a chronic course, which
may, however, eventually have a satisfactory outcome. Nevertheless it carries a
higher mortality correspondingly than does the juvenile variety. The
constitutional disturbance may be less severe and the fluid more often blood-stained
than in the juvenile type. The cytology and cultural characteristics are
otherwise essentially similar in the two varieties. The age incidence of the
post-primary effusion, as might be expected, shows a broader base than does the
primary type, being similar, in fact, to the age incidence in pulmonary
tuberculosis as a whole.
