Saturday, January 15, 2011

Primary Tuberculosis.

Ghon Complex
Tuberculous Granuloma.



develops in a previously unexposed, and therefore unsensitized, person

immunosuppressed persons may lose their sensitivity to the tubercle bacillus and so may develop primary tuberculosis more than once

Morphology

lower part of the upper lobe or the upper part of the lower lobe, usually close to the pleura

Ghon focus consisting of coalescent caseating granuloma

Ghon complex: bacilli brought to the hilar LN elicit caseating granulomatous inflammation in the LNs

cell-mediated immunity controls the infection

nidus for reactivation at a later time when host defenses are compromised

Histological appearance of a tuberculous granuloma:

Rounded outlines.
Central Caseous necrosis.
Transformed macrophages called epithelioid cells.
Lymphocytes, plasma cells, and fibroblasts.
Langhans giant cells.

Primary or Ghon’s Complex

Primary tuberculosis is the pattern seen with initial infection. tuberculosis in children.

Reactivation, or secondary tuberculosis, is more typically seen in adults.

Progressive primary tuberculosis:


In Immunocompromised, malnourished children or in the elderly; the primary infection cannot be controlled resulting in continued proliferation of bacilli and destruction of the parenchyma

absence of the characteristic caseating granulomas (nonreactive tuberculosis)

c/f resembles an acute bacterial pneumonia, with lower and middle lobe consolidation, hilar adenopathy, and pleural effusion; cavitation is rare

Lymphohematogenous dissemination- tuberculous meningitis and miliary tuberculosis.

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