Central nervous system (CNS) tuberculosis (TB) includes three clinical categories: tuberculous meningitis, intracranial tuberculoma, and spinal tuberculous arachnoiditis. All three categories are encountered frequently in regions of the world where the incidence of TB is high and the prevalence of post-primary dissemination is common among children and young adults [1,2]. In regions where the incidence rates are low, such as North America and Western Europe, extrapulmonary manifestations of diseases are seen primarily in adults with reactivation infection, and the dominant form of CNS disease is meningitis.
The pathogenesis, clinical presentation, diagnosis, and treatment of central nervous system tuberculosis will be reviewed here. The general principles of treatment of TB are discussed separately. (See "Treatment of pulmonary tuberculosis in HIV-negative patients".)
During the bacillemia that follows primary infection or late reactivation tuberculosis (TB), scattered tuberculous foci (tubercles) are established in the brain, meninges, or adjacent bone. (See "Microbiology and pathogenesis of tuberculosis".)
The chance occurrence of a subependymal tubercle, with progression and rupture into the subarachnoid space, is the critical event in the development of tuberculous meningitis . The widespread and dense distribution of infectious foci seen in association with progressive miliary tuberculosis greatly increases the chance that juxta-ependymal tubercles will be established. (See "Epidemiology and pathology of extrapulmonary and miliary tuberculosis".)
Consequently, meningitis develops most commonly as a complication of postprimary infection in infants and young children and from chronic reactivation bacillemia in older adults with immune deficiency caused by aging, alcoholism, malnutrition, malignancy, human immunodeficiency virus (HIV) infection, or drugs (eg, tumor necrosis factor [TNF]-alpha inhibitors). Advancing age or head trauma may also lead to destabilization of an established quiescent focus resulting in meningitis in the absence of generalized infection.