Which of the following CSF finding is consistent with TB meningitis?
**Core Concept**
TB meningitis is a form of central nervous system (CNS) tuberculosis that involves the meninges, leading to inflammation and cerebrospinal fluid (CSF) abnormalities. The pathogenesis of TB meningitis is characterized by the spread of Mycobacterium tuberculosis from the lungs to the CNS through the bloodstream, where it causes an intense inflammatory response.
**Why the Correct Answer is Right**
The correct answer is associated with the high protein levels in the CSF, which is a hallmark of TB meningitis. This is due to the breakdown of the blood-brain barrier and the influx of white blood cells into the CSF. Additionally, TB meningitis is characterized by a low glucose level in the CSF due to the consumption of glucose by the bacteria and the inflammatory cells. The lymphocytic predominance in the CSF is also indicative of TB meningitis, as it reflects the body's immune response to the infection.
**Why Each Wrong Option is Incorrect**
**Option A:** Elevated CSF lactate levels are more commonly associated with bacterial meningitis, such as pneumococcal meningitis, rather than TB meningitis.
**Option B:** Normal CSF glucose levels are typically seen in viral meningitis, which is less likely to cause a significant decrease in glucose levels.
**Option C:** A high CSF white blood cell count with a neutrophil predominance is characteristic of bacterial meningitis, such as streptococcal meningitis, rather than TB meningitis.
**Clinical Pearl / High-Yield Fact**
In TB meningitis, the CSF findings often include a low glucose level, high protein level, and lymphocytic predominance. A high red blood cell count in the CSF may also be present due to the disruption of the blood-brain barrier.
**Correct Answer:** C.