A 5-year-old child presents with low-grade fever, irritability, and neck stiffness of two weeks' duration. CSF examination shows 80 cells/μL predominantly lymphocytes, protein 250 mg/dL, glucose 25 mg/dL, and a fine cobweb-like coagulum on standing. The most likely etiological agent is:

• A Streptococcus pneumoniae
• B Mycobacterium tuberculosis ✓
• C Enterovirus
• D Cryptococcus neoformans

Explanation

Tuberculous meningitis produces a chronic lymphocytic meningitis with markedly elevated protein, low glucose, and the characteristic cobweb clot formed by fibrin on standing; AFB may be demonstrated in this clot. Bacterial pyogenic meningitis shows neutrophilic pleocytosis with very low glucose and very high protein over days, not weeks. Viral meningitis has near-normal glucose and protein. Cryptococcal meningitis resembles TB biochemically but the cobweb coagulum and the paediatric age with subacute course favour tuberculosis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.