Infiltration of nonactivated macrophages → escape of humoral immune response
Multi-drug resistance: mutation in KatG (catalase-peroxidase) → INH conversion to its active metabolite → INH resistance
Pathophysiology
Primary tuberculosis
Ghon focus: a granuloma typically located in the middle/lower lung lobes.
Ghon complex: formed by the Ghon focus, regional lymph node, and the linking lymphatic vessels
The organisms can remain dormant in a walled-off Ghon complex for many years before reactivating.
Alternatively, the lesion may heal, forming a benign, calcified Ranke complex that is not associated with reactivation tuberculosis.
Secondary tuberculosis
In < 10% of individuals with primary TB, the host immune response fails to control the infection, leading to active primary TB and progressive disease.
In > 90% of individuals, the host immune response can control the infection, resulting in latent TB infection. Weakening of host immune response can allow reactivation of disease (or, less commonly, reinfection) and further disease progression.
Clinical features
Diagnostics
Treatment
Side effects of antituberculosis agents
Isoniazid
Asymptomatic elevation of transaminases
Cytochrome P450 inhibition: leading to interactions with numerous drugs, including antiretroviral agents, cardiovascular agents, and antibiotics
