infectious diseases
Tuberculosis (TB)
Key Points
Tuberculosis causes a primary, often asymptomatic infection followed by latent infection and, in a few patients, an active disease phase. About one fourth of the world's population is infected with tuberculosis, and about 15 million have active disease at a given time. Active disease is much more likely in patients with impaired immunity, particularly those with HIV infection. Suspect the diagnosis based on symptoms, risk factors, tuberculin skin testing, and interferon-gamma release assays; confirm by sputum testing (microscopic examination and culture) and/or nucleic acid amplification tests. Treat with multiple drugs for several months. Drug resistance is a major concern and is increased by poor adherence, use of inappropriate drug regimens, and inadequate susceptibility testing. 