Fundus of patient with disseminated TB shows.
**Core Concept**
Disseminated tuberculosis (TB) is a clinical manifestation of TB that involves multiple organs, including the lungs, liver, spleen, and eyes. In the context of ocular TB, the fundus examination is crucial for diagnosing and monitoring the disease.
**Why the Correct Answer is Right**
The fundus in a patient with disseminated TB may show choroidal tubercles, which are small, yellowish lesions in the choroid layer of the eye. These tubercles are formed due to the hematogenous spread of TB bacilli from the primary site of infection. The choroid is richly supplied with blood vessels, and the TB bacilli can easily lodge and multiply within these vessels, leading to the formation of tubercles. The presence of choroidal tubercles is a characteristic finding in ocular TB.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because it is not a characteristic finding in ocular TB. While retinal vasculitis and ischemia can occur in TB, they are not specific to ocular TB and can be seen in other inflammatory conditions.
**Option B:**
This option is incorrect because it is not a typical finding in ocular TB. While vitreous inflammation can occur in TB, it is more commonly associated with posterior uveitis, which is not specific to ocular TB.
**Option C:**
This option is incorrect because it is not a characteristic finding in ocular TB. While optic neuritis can occur in TB, it is more commonly associated with direct invasion of the optic nerve by TB bacilli, which is not the primary mechanism of ocular TB.
**Clinical Pearl / High-Yield Fact**
Remember that ocular TB is a rare but serious complication of disseminated TB, and the presence of choroidal tubercles is a characteristic finding that should prompt further investigation and treatment.
**Correct Answer:** A.