CSF Analysis Interpretation for Tuberculous Meningitis

The patient presents with symptoms of fever and altered sensorium. Cerebrospinal fluid (CSF) analysis provides key diagnostic clues. Analyzing the CSF results helps differentiate various types of meningitis.

Evaluating CSF Findings

• Pressure: Raised pressure indicates increased intracranial pressure, common in meningitis.
• Appearance: Opalescent fluid with "cobweb formation" upon standing is highly suggestive of Tuberculous meningitis, although it can sometimes be seen in fungal meningitis. This appearance is due to high protein and fibrin content.
• Protein: Markedly elevated at `$220 \text{ mg\%}$' (normal is typically 15-45 mg%). This signifies significant inflammation and disruption of the blood-brain barrier.
• Sugar: Significantly low at `$30 \text{ mg\%}$' (normal is ~60% of serum glucose, usually 45-80 mg%). Low glucose indicates increased consumption by microorganisms (like Mycobacterium tuberculosis) or inflammatory cells within the CSF.
• Cells: A high count of `$1250 \text{ cells per field}$' with a predominance of lymphocytes (lymphocytic pleocytosis) points towards a chronic or subacute inflammatory process, characteristic of viral, fungal, or tuberculous meningitis, rather than acute bacterial meningitis which typically shows neutrophils.
• Globulin: Positive result confirms the presence of increased protein levels.

Differential Diagnosis based on CSF Profile

Comparing the CSF profile with common meningitis types:

• Meningococcal meningitis: Typically shows neutrophilic pleocytosis, moderate protein elevation, and normal/low sugar. The lymphocytic predominance and very high protein here make it less likely.
• Subarachnoid haemorrhage: CSF would show red blood cells and xanthochromia. The findings here are not consistent with a bleed.
• Cryptococcal meningitis: Can show lymphocytic pleocytosis, low sugar, and high protein. However, the classic "cobweb formation" is more specifically associated with Tuberculous meningitis.
• Tuberculous meningitis: The combination of raised pressure, opalescent fluid with cobweb formation, very high protein, low sugar, and lymphocytic pleocytosis is classic for Tuberculous meningitis.

Therefore, based on the provided CSF analysis, Tuberculous meningitis is the most likely diagnosis.