**Core Concept**
Cerebrospinal fluid (CSF) analysis plays a crucial role in diagnosing tuberculous meningitis (TBM), a form of meningitis caused by Mycobacterium tuberculosis. The CSF findings in TBM are characterized by a chronic inflammatory response, which leads to specific alterations in the CSF composition.

**Why the Correct Answer is Right**
The CSF in TBM typically shows elevated protein levels, decreased glucose levels, and an increased white blood cell count, predominantly lymphocytes. This is due to the breakdown of the blood-brain barrier and the activation of immune cells, such as macrophages and T-lymphocytes, which attempt to combat the infection. The decreased glucose levels are a result of the impaired glucose transport across the blood-brain barrier, while the elevated protein levels reflect the increased permeability of the blood-brain barrier.

**Why Each Wrong Option is Incorrect**
**Option A:** Elevated CSF lactate levels are not a specific finding in TBM.
**Option B:** A normal CSF glucose level is not typical of TBM.
**Option C:** A decreased CSF white blood cell count is not characteristic of TBM.

**Clinical Pearl / High-Yield Fact**
In TBM, the CSF protein-to-glucose ratio is often greater than 1:100, which can help differentiate it from other forms of meningitis.

**Correct Answer: C. Elevated protein levels, decreased glucose levels, and an increased white blood cell count, predominantly lymphocytes.**