All are the features of primary TB except
**Core Concept**
Primary tuberculosis (TB) is the initial infection with Mycobacterium tuberculosis in a person who has no prior immunity. It is characterized by the formation of a primary complex, which includes a Ghon focus in the lung and associated lymphadenopathy.
**Why the Correct Answer is Right**
The primary complex is formed due to the local immune response to the bacterium, which involves the activation of macrophages and the release of cytokines such as TNF-alpha and IFN-gamma. This leads to the formation of a granuloma, a type of organized immune response that attempts to wall off the infection. The Ghon focus is a characteristic feature of primary TB, representing the site of initial infection in the lung. The associated lymphadenopathy is also a key feature of primary TB, resulting from the spread of the infection to the regional lymph nodes.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because cavitation is more commonly associated with post-primary TB, which occurs in individuals who have some level of immunity to the bacterium. Cavitation is a result of the destruction of lung tissue by the infection.
**Option B:** This option is incorrect because hemoptysis is a feature of advanced TB, particularly in the context of pulmonary TB. It is not typically seen in primary TB.
**Option C:** This option is incorrect because miliary TB is a dissemination of TB infection to multiple parts of the body, including the lung, liver, and spleen. It is not a feature of primary TB.
**Clinical Pearl / High-Yield Fact**
One key feature of primary TB is that it often resolves spontaneously, resulting in a healed Ghon focus. However, the infection can reactivate in the future, leading to post-primary TB.
**Correct Answer:** D.