Pulmonary tuberculosis

Pulmonary tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis.

Key risk factors include exposure to infection, birth in an endemic country, and HIV infection.

Symptoms may include cough, fever, and weight loss.

If pulmonary TB is suspected, the patient should be isolated, a chest x-ray obtained, and three sputum samples collected for acid-fast bacilli smear and culture; nucleic acid amplification test should be performed on at least one respiratory specimen.

Directly observed therapy is highly recommended and is particularly indicated in groups where adherence cannot be assumed.

Early recognition and implementation of effective treatment for infectious TB is crucial in interrupting TB transmission.

In many patients, Mycobacterium tuberculosis becomes dormant before it progresses to active TB. TB most commonly involves the lungs (pulmonary TB) and is communicable in this form, but may affect almost any organ system including the lymph nodes, central nervous system, liver, bones, genitourinary tract, and gastrointestinal tract. See Extrapulmonary tuberculosis.