Study of respiratory symptoms among sputum positive

Also, smoking was recognized as a toxic factor capable ofreducing host
immune defense mechanism (Crofton et al., 1992), and reported to disturb
oxidant lanti-oxidant homeostasis via attraction and stimulation of
macrophages and neutrophils liberating oxidants (Mobasher, 1993).
6) Steriod and other immunosuppressent drugs In
immunocompromised patients, tuberculosis is most often the result of
reactivation of a latent focus, but it is some times a primary infection.
In such patients, tuberculosis is usually more sever and rapidly
progressive than in immunocompetent patients, mortality is higher, and
extrapulmonary involvement is more frequent (Barnes et al., 1991).
In all immunosuppressed patients, the morphology oftuberculous
lesions reflects poor host resistance. As, in corticosteriod- treated patients,
tuberculous lesions show abundant caseation with little or no encapsulation
or granulamatous reaction. Large numbers ofbacteria are usually present
within the lesions (Dannenberg and Tomasbefski, 1998 ).
7) Other diseases : Diseases associated with impaired cellular immunity
such as Hodgkin's disease, leukemia, lymphoma and AIDS may
predispose to reactivation (Lovie et al., 1986 and Handwerger et aI.,
1987). Diabetes mellitus potentiates TB through (Mobasber, 1993) :
a) compromising the host defense mechanisms.
b) Producing local tissue acidosis and electrolyte imbalance, that impair
repair.
c) Favoring the growth and viability of the bacilli by increasing sugar
glycerol and nitrogenous substances in the blood
34