A 35-year-old man presents with 10 days of fever, headache, vomiting, and progressive confusion. He has a history of pulmonary tuberculosis. Neck stiffness is present. CSF shows glucose 1.8 mmol/L (serum 5.2), protein 3.2 g/L, and lymphocytes 450 cells/mm³. Which investigation is most likely to confirm the diagnosis?

• A CSF GeneXpert MTB/RIF ✓
• B CSF Gram stain and culture
• C CSF India ink staining
• D CSF viral PCR panel

Explanation

The subacute presentation with very low CSF glucose, markedly elevated protein, and lymphocytic pleocytosis in a patient with TB exposure is classic for tuberculous meningitis. GeneXpert MTB/RIF on CSF is the best rapid diagnostic test. Gram stain targets bacterial meningitis. India ink is for cryptococcosis, which causes moderate hypoglycorrhachia, not this severe.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.