Indexed on: 02 Apr '11Published on: 02 Apr '11Published in: Mayo Clinic Proceedings
Tuberculosis (TB) poses a serious threat to public health throughout the world but disproportionately afflicts low-income nations. Persons in close contact with a patient with active pulmonary TB and those from endemic regions of the world are at highest risk of primary infection, whereas patients with compromised immune systems are at highest risk of reactivation of latent TB infection (LTBI). Tuberculosis can affect any organ system. Clinical manifestations vary accordingly but often include fever, night sweats, and weight loss. Positive results on either a tuberculin skin test or an interferon-γ release assay in the absence of active TB establish a diagnosis of LTBI. A combination of epidemiological, clinical, radiographic, microbiological, and histopathologic features is used to establish the diagnosis of active TB. Patients with suspected active pulmonary TB should submit 3 sputum specimens for acid-fast bacilli smears and culture, with nucleic acid amplification testing performed on at least 1 specimen. For patients with LTBI, treatment with isoniazid for 9 months is preferred. Patients with active TB should be treated with multiple agents to achieve bacterial clearance, to reduce the risk of transmission, and to prevent the emergence of drug resistance. Directly observed therapy is recommended for the treatment of active TB. Health care professionals should collaborate, when possible, with local and state public health departments to care for patients with TB. Patients with drug-resistant TB or coinfection with human immunodeficiency virus should be treated in collaboration with TB specialists. Public health measures to prevent the spread of TB include appropriate respiratory isolation of patients with active pulmonary TB, contact investigation, and reduction of the LTBI burden.