Diagnosing tuberculous meningitis - have we made any progress?

Tuberculous meningitis (TBM) comprises a significant proportion of TB cases globally and causes substantial morbidity and mortality, especially in children and HIV-infected patients. It is a challenging condition to diagnose due to its non-specific clinical presentation and the limited sensitivity of existing laboratory techniques. Smear microscopy and culture are the most widely available diagnostic tools yet are negative in a significant proportion of TBM cases. Simplified and more affordable nucleic acid amplification tests (NAATs) are increasing in use in resource-limited settings but have not been optimised for cerebrospinal fluid (CSF) samples. Novel diagnostic methods such as CSF interferon-gamma release assays and various biomarkers have been developed but require further evaluation to establish their utility as diagnostic tools. There is an urgent need for further research into optimal diagnostic strategies to decrease the morbidity and mortality as a result of delayed or missed diagnosis of TBM. In this review, we discuss current and novel diagnostic tests in TBM and areas where future research should be prioritised.