Tuberculosis
Of all the lung diseases caused by bacteria, pulmonary tuberculosis is
historically by far the most important. Particular features of this dreaded
condition include the severe general debilitation and weakness that it
may cause; the insidious nature of the onset of its initial symptoms,
which may not be pulmonary in nature; the familial tendency; the longdrawn-out course of the disease and the distressing nature of many of
its manifestations, particularly severe hemorrhage from the lung and
from tuberculous involvement of the brain (meningitis), or involvement
of the adrenal gland leading to adrenal insufficiency (Addison disease);
and, above all, the general inefficacy of medical treatment before
effective antibiotic therapy became available. Antibiotics have greatly
reduced the mortality from pulmonary tuberculosis in all developed
countries, but the decline in mortality began well before their
introduction, and it is clear that improved diet and housing were
responsible for this. With antibiotic therapy, however, the bacilli quickly
disappear from the sputum and the spread of infection is quickly
controlled.
In its classic form, tuberculosis first causes pulmonary inflammation at
the apices (upper portions) of the lungs, and it may progress slowly to
form a chronic cavity in this region. When still active, pulmonary
tuberculosis is a constant threat to the patient, because blood-borne
spread may occur at any time.
Treatment of tuberculosis is based on whether an individual has
tuberculosis infection or tuberculosis disease. Treatment of the former
is aimed at preventing disease and often involves only one drug,