Patient with fever had a lumbar puncture done as part of workup for fever. The CSF revealed high proteins with normal sugar and marked increase in lymphocytes. The diagnosis is likely to be –
**Core Concept**
The patient's cerebrospinal fluid (CSF) profile, characterized by high protein levels, normal glucose levels, and a marked lymphocytic pleocytosis, is indicative of a chronic or subacute inflammatory process within the central nervous system (CNS). This profile is often seen in conditions such as viral encephalitis, chronic meningitis, or CNS infections caused by viruses or certain bacteria.
**Why the Correct Answer is Right**
The presence of high protein levels in the CSF is due to the disruption of the blood-brain barrier, allowing proteins to leak into the CSF. Normal glucose levels in the CSF suggest that the glucose is being utilized by the cells within the CNS, which is a characteristic feature of chronic infections. The marked lymphocytic pleocytosis (increased lymphocytes) indicates an immune response within the CNS, with lymphocytes being the primary cells involved in fighting off infections. This profile is consistent with viral encephalitis, such as herpes simplex encephalitis.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not match the CSF profile described. Tuberculous meningitis typically presents with low glucose levels in the CSF and a lymphocytic pleocytosis, but the protein levels are usually not as high as described.
* **Option B:** This option is incorrect as it does not match the CSF profile described. Bacterial meningitis typically presents with high glucose levels in the CSF and a neutrophilic pleocytosis, rather than lymphocytes.
* **Option C:** This option is incorrect as it does not match the CSF profile described. Fungal meningitis typically presents with low glucose levels in the CSF and a lymphocytic pleocytosis, but the protein levels are usually not as high as described.
**Clinical Pearl / High-Yield Fact**
In cases of chronic meningitis or CNS infections, the CSF profile may evolve over time, making it essential to repeat CSF analysis and consider the clinical context when interpreting the results. A repeat analysis may reveal changes in the CSF profile that can help guide treatment.
**Correct Answer: A.**