A 5-year-old child is diagnosed with tuberculous meningitis and started on four-drug antitubercular therapy. At 6 weeks of treatment he develops sudden onset diplopia and inability to abduct the right eye. Fundoscopy is normal. What is the most likely mechanism of this complication?

• A Optic nerve infiltration by tubercle bacilli
• B Hydrocephalus compressing the optic chiasm
• C Raised intracranial pressure causing papilledema
• D Cranial nerve palsy due to basilar exudates and vasculitis ✓

Explanation

Cranial nerve palsies, most commonly CN VI followed by CN III, IV, and VII, occur in tuberculous meningitis due to basilar inflammatory exudates causing entrapment, vasculitis, and ischemic neuropathy of cranial nerves. This typically appears during the first weeks of treatment. Papilledema would be visible on fundoscopy. Hydrocephalus causes sunsetting and macrocephaly rather than isolated CN palsies.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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