Adjunctive Corticosteroids for Tuberculous Meningitis in HIV-infected Adults (The ACT HIV Trial)

Inclusion Criteria: * Adult (18 years or older) * HIV-infected * Clinical diagnosis of TBM (≥5 days of meningitis symptoms, and CSF abnormalities) and anti-tuberculosis chemotherapy either planned or started by the attending physician Note: Published diagnostic criteria will be applied to all enrolled participants at the end of the study when all mycobacterial culture results are available. The criteria will sub-divide all cases into definite, probable and possible TBM, and those with an alternative diagnosis. Exclusion Criteria: * An additional brain infection (other than TBM) confirmed or suspected: positive CSF Gram or India Ink stain; positive blood or CSF Cryptococcal antigen test; cerebral toxoplasmosis suspected and attending physician wants to give anti-toxoplasmosis treatment with anti-tuberculosis treatment * More than 6 consecutive days of two or more drugs active against M. tuberculosis immediately before screening * More than 3 consecutive days of any type of orally or intravenously administered corticosteroid immediately before randomisation * Dexamethasone considered mandatory for any reason by the attending physician * Dexamethasone considered to be contraindicated for any reason by the attending physician * Previously been randomised into the trial for a prior episode of TBM * Lack of consent from the participant or family member (if the participant is incapacitated by the disease)