Definite (microbiologically confirmed) tuberculous meningitis: predictors and prognostic impact

Microbiological confirmation cannot be obtained in approximately two-third patients with tuberculous meningitis. In this study, we sought to identify epidemiological, clinical, cerebrospinal fluid, and imaging parameters that could indicate the possibility of microbiological confirmation among patients with suspected tuberculous meningitis.

In this prospective observational study, patients with tuberculous meningitis were evaluated for clinical, laboratory (cerebrospinal fluid microscopy, culture, and polymerase chain reaction), and neuroimaging parameters. All patients received anti-tuberculosis drugs and corticosteroids. The patients were followed for a period of 6 months.

Among 118 cases of tuberculous meningitis, there were 43 (36 %) definite (microbiologically confirmed) cases, 59 (50 %) probable and 16 (14 %) possible cases. Among 43 definite cases, tuberculosis polymerase chain reaction (PCR) was positive in 42 (35 %) patients, culture was positive in 1 case and microscopy, after Ziehl–Neelsen staining, was positive in 3 cases. Three factors, modified Barthel index score at admission ≤12 (p = 0.008), cerebrospinal fluid total cell count >100/mm³ (p = 0.016), and basal exudates on imaging (p = 0.015), were significantly associated with definite tuberculous meningitis. Among 20 patients who died within 6 months, 13 belonged to definite tuberculous meningitis group (p < 0.001). Stage III tuberculous meningitis (p = 0.004), baseline-modified Barthel index score ≤12 (p = 0.013), and positive tuberculosis PCR (p = 0.007) were independently associated with poor outcome on multivariate analysis.

Severe disability, cerebrospinal fluid cells >100 mm³, and basal exudates are significantly related to the presence of microbiologically confirmed definite tuberculous meningitis. Microbiologically confirmed tuberculous meningitis is associated with poorer outcome.