Despite the availability of curative therapy and a widely used vaccine, tuberculosis is one of the greatest threats to human health and continues to cause enormous suffering, disability and death. Infections with Mycobacterium tuberculosis cause a wide array of clinical manifestations, ranging from asymptomatic latent infection to disseminated and fulminant disease. Tuberculosis is generally regarded as a respiratory infection, but early in M. tuberculosis infection the organism is hematogenously disseminated and takes up residence in a number of organs, including the central nervous system. Tuberculosis affects the central nervous system in three principal ways: tuberculous meningitis, tuberculomas of the brain and spinal cord, and vertebral tuberculosis, or Pott's disease, an infection of vertebrae and paraspinous areas that can lead to destabilization of the spinal cord with potentially devastating neurological consequences. The purpose of this chapter is to describe the neurologic manifestations of tuberculosis and discuss its diagnosis and management.

Epidemiology

Tuberculosis remains a global problem with 8 million new cases per year and approximately 2 million deaths. Twentytwo countries account for 80% of all tuberculosis cases, and the case rate in developing countries is approximately sevenfold higher than in industrialized nations. Globally, increasing rates of HIV-related tuberculosis have been noted in areas where tuberculosis infection is endemic and HIV is epidemic. Tuberculosis is the most common opportunistic infection in people with HIV, and more HIVinfected individuals die from tuberculosis than any other cause. In many countries where HIV is not prevalent, tuberculosis remains a common cause of disability and death, primarily affecting young adults.

M. tuberculosis epidemiology can be divided into two components based on the natural history of the organism in humans: latent infection with M. tuberculosis, which is acquired from infectious cases of tuberculosis, and tuberculosis disease, which results from either primary or remote progression of a latent infection to clinical illness. Risk factors for acquiring tuberculosis infection include close contact with an infectious case, often in the same household or workplace, or exposure to air shared by infectious tuberculosis patients, such as in health care facilities or in public places in high prevalence communities. Socioeconomic factors associated with tuberculosis infection generally reflect an increased likelihood of exposure to others with active disease. Risk factors for developing active tuberculosis disease include recent infection, large inoculum, and impaired cellular immunity, such as with HIV infection or pharmacological immunosuppression.