Overview
Central nervous system tuberculosis (CNS-TB) is a serious extrapulmonary manifestation of tuberculosis, accounting for a significant proportion of TB cases and carrying high morbidity and mortality 1. It encompasses tuberculous meningitis (TBM), intra-cerebral tuberculoma, and spinal cord tuberculosis 2.Diagnosis
TBM is suspected with CSF findings of leucocytosis (predominantly lymphocytes), elevated protein, and a CSF:plasma glucose ratio <50% 2.
Lumbar puncture and CSF examination are the primary diagnostic methods for TBM 2.
The diagnostic yield of CSF microscopy and culture for Mycobacterium tuberculosis* improves with larger CSF volumes; repeat lumbar puncture may be necessary if diagnosis remains uncertain 2.
Imaging is essential for diagnosing cerebral tuberculoma and spinal cord tuberculosis, though radiological findings are not confirmatory 2.
A tissue diagnosis via histopathology and mycobacterial culture should be attempted when possible, either from the lesion or extra-neural sites 2.
The global prevalence of CNS-TB is estimated at 2 per 100,000 inhabitants 1.Management
TBM is a medical emergency, and prompt empirical anti-tuberculosis therapy is recommended in all suspected cases, without waiting for microbiological confirmation 2.Key Recommendations
Tuberculous meningitis (TBM) is a medical emergency. Empirical anti-tuberculosis therapy should be started promptly in all patients in whom the diagnosis of TBM is suspected, without waiting for microbiological or molecular diagnostic confirmation. (Evidence: Expert opinion)
The diagnosis of TBM is best made with lumbar puncture and examination of the cerebrospinal fluid (CSF). Suspect TBM if there is a CSF leucocytosis (predominantly lymphocytes), the CSF protein is raised, and the CSF:plasma glucose is <50%. (Evidence: Expert opinion)
Imaging is essential for the diagnosis of cerebral tuberculoma and tuberculosis involving the spinal cord, although the radiological appearances do not confirm the diagnosis. A tissue diagnosis (by histopathology and mycobacterial culture) should be attempted whenever possible, either by biopsy of the lesion itself, or through diagnostic sampling from extra-neural sites of disease. (Evidence: Expert opinion)References
1 Navarro-Flores A, Fernandez-Chinguel JE, Pacheco-Barrios N, Soriano-Moreno DR, Pacheco-Barrios K. Global morbidity and mortality of central nervous system tuberculosis: a systematic review and meta-analysis. Journal of neurology 2022. link
2 Thwaites G, Fisher M, Hemingway C, Scott G, Solomon T, Innes J. British Infection Society guidelines for the diagnosis and treatment of tuberculosis of the central nervous system in adults and children. The Journal of infection 2009. link