Tuberculosis and human immunodeficiency virus infection

Because of the abnormalities of host defenses caused by the human immunodeficiency virus (HIV), persons with HIV infection are vulnerable to tuberculosis. Inferential data from several parts of the country indicate increases in tuberculosis case rates, probably occurring in patients with HIV infection. In a person infected with both HIV and Mycobacterium tuberculosis, attack rates of tuberculosis seem to be very high. In general, the disease tends to occur earlier in the course of HIV infection than other opportunistic processes that serve to define the acquired immunodeficiency syndrome (AIDS), presumably because M tuberculosis is more pathogenic than Pneumocystis carinii or Mycobacterium avium complex, for example. The clinical features of tuberculosis in this patient population seem to vary depending on the stage of the HIV infection. Late in the process, tuberculosis usually has atypical features with chest films showing diffuse infiltration, no cavities, and intrathoracic adenopathy. Tuberculin skin tests commonly are negative. At earlier stages of HIV infection, the clinical findings are similar to those in HIV-seronegative persons. Response to treatment is generally good; however, it is recommended that the standard duration be at least 9 months, using isoniazid and rifampin usually supplemented by pyrazinamide in the first 2 months. The use of isoniazid for preventive therapy is recommended for all HIV-seropositive persons who have tuberculin skin test reactions greater than or equal to 5 minutes. Those implementing infection-control measures for HIV-infected patients who have pulmonary findings should take tuberculosis into account until the disease is excluded. Medical personnel providing care for patients with tuberculosis should use universal blood and body substance precautions because of the possibility of undetected HIV infection in patients with tuberculosis.