A 30-year-old man from a rural area presents with 2 weeks of fever, headache, and altered sensorium. CSF shows protein 280 mg/dL, glucose 1.8 mmol/L (serum 6.5 mmol/L), and 300 cells (90% lymphocytes). Contrast MRI shows basal cistern exudates and hydrocephalus. The most characteristic CSF finding distinguishing this from viral meningitis is

• A Lymphocytic pleocytosis
• B Markedly elevated CSF protein ✓
• C Low CSF glucose
• D Opening pressure greater than 25 cmH2O

Explanation

In tuberculous meningitis, CSF protein is markedly elevated, often 100-500 mg/dL, due to intense inflammatory exudates in the basal cisterns. While low glucose and lymphocytosis also occur, the very high protein is the most distinguishing feature from viral meningitis, where protein is normal or mildly elevated. Hydrocephalus and basal enhancement on imaging are characteristic of TB meningitis.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.