Central nervous system tuberculosis: pathogenesis and clinical aspects

Abstract

Tuberculosis of the central nervous system (CNS) is a highly devastating form of tuberculosis, which, even in the setting of appropriate antitubercular therapy, leads to unacceptable levels of morbidity and mortality. Despite the development of promising molecular diagnostic techniques, diagnosis of CNS tuberculosis relies largely on microbiological methods that are insensitive, and as such, CNS tuberculosis remains a formidable diagnostic challenge. Insights into the basic neuropathogenesis of Mycobacterium tuberculosis and the development of an appropriate animal model are desperately needed. The optimal regimen and length of treatment are largely unknown, and with the rising incidence of multidrug-resistant strains of M. tuberculosis, the development of well-tolerated and effective antibiotics remains a continued need. While the most widely used vaccine in the world largely targets this manifestation of tuberculosis, the BCG vaccine has not fulfilled the promise of eliminating CNS tuberculosis. We put forth this review to highlight the current understanding of the neuropathogenesis of M. tuberculosis, to discuss certain epidemiological, clinical, diagnostic, and therapeutic aspects of CNS tuberculosis, and also to underscore the many unmet needs in this important field.

FIG. 1.

Murine model of CNS tuberculosis. (A) Coronary section at the level of the caudal diencephalon, with multifocal nonsuppurative encephalitis. Hematoxylin and eosin (HE) staining was used. Bar, 500 μm. (B) Cornu ammonis showing mild perivascular lymphocytic and histiocytic infiltration, with microgliosis and reactive astroglia. HE staining was used. Bar, 100 μm. The inset shows M. tuberculosis bacillus in a perivascular macrophage. Acid-fast staining was used. Magnification, ×600. (C) Dorsal third ventricle, choroid plexus, and subependymal areas expanded by lymphocytic, plasmacytic, and histiocytic infiltration, with subependymal microgliosis and reactive astroglia. HE stain. Bar, 50 μm. (Courtesy of Anibal Armien.)

FIG. 2.

MRI of CNS tuberculoma. Contrast-enhanced scans show CNS tuberculoma.