Tuberculous meningitis in HIV — DTM&H MCQ

Correct answer: B — Antituberculous therapy with adjunctive corticosteroids

The correct answer is B, antituberculous therapy with adjunctive corticosteroids. This patient has a lymphocytic, high protein, low glucose CSF picture with a positive Xpert MTB/RIF and no rifampicin resistance, which confirms tuberculous meningitis (TBM) rather than an alternative pathogen. Standard of care is a minimum four-drug antituberculous regimen (rifampicin, isoniazid, pyrazinamide, ethambutol) alongside adjunctive corticosteroids (dexamethasone or prednisolone), which reduce the intracerebral inflammatory response and improve survival. British Infection Society guidance, still the reference UK standard for CNS TB, states that adjunctive corticosteroids should be given to all patients with TBM regardless of severity, and this applies to HIV-positive patients too since no better adjunctive option exists. Xpert MTB/RIF confirming rifampicin susceptibility means a standard first-line regimen is appropriate rather than a drug-resistant protocol. Why the other options are wrong: A, ceftriaxone for 48 hours then stop: this targets bacterial meningitis, but the CSF profile (lymphocytic, low glucose, high protein) and positive Xpert are diagnostic of TB, not a pyogenic organism responsive to short-course cephalosporin. B, fluconazole monotherapy pending culture: this would treat cryptococcal meningitis, a key differential in advanced HIV, but the positive Xpert MTB/RIF result already confirms the causative organism as Mycobacterium tuberculosis, making empirical antifungal treatment inappropriate here. C, albendazole and dexamethasone: this combination treats neurocysticercosis, which typically causes focal seizures or space-occupying lesions rather than a subacute lymphocytic, low-glucose meningitis, and does not address confirmed mycobacterial infection. E, immediate ART before TB treatment: starting ART before antituberculous therapy in TBM increases the risk of CNS immune reconstitution inflammatory syndrome (IRIS), which can be fatal; ART should be deferred and introduced cautiously once TB treatment is established, per HIV-TB co-treatment guidance. Key point: A positive CSF Xpert MTB/RIF in a lymphocytic, low-glucose, high-protein meningitis picture mandates antituberculous therapy plus adjunctive corticosteroids, irrespective of HIV status.

Reference: British Infection Society Guidelines for the Diagnosis and Treatment of Tuberculosis of the Central Nervous System in Adults and Children (Thwaites et al., J Infect 2009), recommendation that adjunctive corticosteroids (dexamethasone or prednisolone) be given to all patients with tuberculous meningitis regardless of severity; PubMed https://pubmed.ncbi.nlm.nih.gov/19643501/