A 4-year-old with 3 weeks of low-grade fever and weight loss now has vomiting and neck stiffness. CSF: 180 cells/uL with 80% lymphocytes, protein 350 mg/dL, glucose 22 mg/dL (blood glucose 110 mg/dL). The fluid forms a fine cobweb-like coagulum on standing overnight. Which additional CSF parameter would support the most likely diagnosis?

• A Elevated CSF chloride above 130 mEq/L
• B Elevated adenosine deaminase activity ✓
• C Positive India ink preparation
• D Neutrophil predominance exceeding 90%

Explanation

The chronic lymphocytic meningitis with markedly raised protein, very low glucose relative to blood, and the characteristic cobweb coagulum (from fibrin) indicates tuberculous meningitis. Elevated CSF adenosine deaminase supports the diagnosis and is used as an adjunct marker. Cryptococcal meningitis also gives low glucose with lymphocytes, but India ink positivity would itself define cryptococcus, and CSF chloride falls, not rises, in pyogranulomatous meningitis.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.