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The first 200 words of this essay...
Types , Pathogenesis & Clinical Picture of Tuberculosis
PRIMARY INFECTION (usually in children)
It is response to first exposure to M. tuberculosis.
Usually pulmonary infection - at periphery of mid zone of lung (sub-pleura)
TB bacilli are engulfed by macrophages - those survive multiply in macrophages ? carried to hilar lymph nodes
Dissemination to other organs through blood stream can occur
Cell mediated immunity & Hypersensitivity
Develop 2-6 weeks after infection.
Macrophages containing TB bacilli present to competent
T-lymphocytes? lymphokines ? attract monocytes and transform them to activated macrophages ? surround the infected area ? slow down bacterial multiplicaiton.
° Leads to granuloma formation
Tubercle (microscopic granuloma) formation at subpleural area
Consists of :
Many epithelioid cells (activated macrophages)
Multinucleated giant cells (formed by fusion of macrophages)
Surrounded by lymphocytes
° Known as Ghon focus.
1. Occur due to reactivation of an old focus in elderly due to:
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