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.
History and exam
Key diagnostic factors
- weight loss
Other diagnostic factors
- night sweats
- pleuritic chest pain
- psychological symptoms
- abnormal chest auscultation
- erythema nodosum and erythema induratum
- exposure to infection
- birth in an endemic country
- HIV infection
- immunosuppressive medications
- end-stage renal disease
- apical fibrosis
- intravenous drug use
- high-risk congregate settings
- low socioeconomic status or black/Hispanic/Native-American ancestry
- tobacco smoking
1st investigations to order
- chest x-ray
- sputum acid-fast bacilli smear
- sputum culture
- CBC (complete blood count)
- nucleic acid amplification tests (NAAT)
Investigations to consider
- gastric aspirate
- bronchoscopy and bronchoalveolar lavage
- stool testing
- tuberculin skin testing
- interferon-gamma release assays
- empiric treatment
- drug susceptibility testing
- HIV test
- lateral flow urine lipoarabinomannan (LF-LAM) assay
- CT of chest
- TB antigen-based skin tests (TBSTs)
latent TB infection: nonpregnant
latent TB infection: pregnant
active TB HIV-negative nonpregnant: no hepatic dysfunction
active TB HIV-positive nonpregnant: no hepatic dysfunction
active TB pregnant
active TB non-pregnant: pre-existing or drug-induced hepatic dysfunction
- Coronavirus disease 2019 (COVID-19)
- Community-acquired pneumonia
- Lung cancer
- WHO consolidated guidelines on tuberculosis: module 4: treatment: drug-susceptible tuberculosis
- WHO consolidated guidelines on tuberculosis: module 4: treatment: drug-resistant tuberculosis treatment, 2022 update
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