How is pathophysiology of TB?

Spread through inhalation of infected aerosols, genetics and immunity play a role in defense, although TB comes with virulence factors to alveolar macrophages. Primary TB is first contact with M.tb, usually in middle portion of lungs known as Ghon focus (usually goes latent) Then when pt is immunocompromised, latent infection maybe reactivated (only small portion of people get activated without latency - primary progressive TB seen in children, malnutrition...) Secondary TB is activation of latent TB, causes lesions in lung apices Secondary TB sometimes may be caused by reinfection of M.tb