Tuberculosis in HIV Infection

Abstract

Persons with AIDS (PWAs) are 100 times more likely to develop tuberculosis (TB) than the general population. The TB incidence rates in PWAs in the US range from 4-21%, especially among intravenous drug users and Haitians. In Florida, 60% of Haitian AIDS patients also had TB compared to 2.7% of non-Haitian AIDS patients. At a hospital in London, England, 25% of PWAs also had TB and 42% of all AIDS patients at this hospital were members of racial groups with a high prevalence of TB. In developed countries, reactivation of a latent TB infection is generally what occurs in AIDS patients. The absolute number of AIDS patients with TB in these countries is low and unlikely that it will spread to non-HIV seropositive patients. On the other hand, 30-60% of adults have been infected with Mycobacterium tuberculosis in central Africa and HIV seroprevalence is also high. So many AIDS patients here can develop TB through reactivation or exogenous primary infection. This situation significantly increases the risk of TB for HIV seronegative persons. In fact, TB is 1 of the most frequent opportunistic infections in PWAs in developing countries, such as central Africa. In patients at an early stage of HIV infection, TB manifests itself classically. The clinical presentation in patients in the late stages includes fever, weight loss, malaise, productive cough accompanied with labored breathing, an atypical chest radiograph, and extrapulmonary TB. This atypical pattern often results in delays of diagnosis and treatment. Many sputum samples do not test positive for M. tuberculosis therefore if a physician suspects TB, treatment should begin immediately. Some studies demonstrate that isoniazid prophylaxis substantially decreases the incidence of TB in HIV seropositive patients in Zambia. There is no conclusive evidence of the harm or effectiveness of the BCG vaccine in HIV children and adults.