Tuberculosis
Also called: TB, Pulmonary tuberculosis
A bacterial infection spread through the air, usually affecting the lungs. It is curable with a long course of antibiotics, yet remains one of the world's deadliest infectious diseases.
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About 10 million people fall ill each year; a quarter of the world's population carries latent infection.
What happens in the body
Mycobacterium tuberculosis is inhaled and walled off in granulomas (latent TB). If immunity falls, bacteria reactivate and destroy lung tissue, typically forming cavities in the upper lobes.
Causes
- Mycobacterium tuberculosis spread by airborne droplets
Risk factors
- Close contact with an infectious person
- HIV infection
- Diabetes, malnutrition, smoking
- Immunosuppressive drugs (including anti-TNF)
- Living or travelling in high-burden regions
- Homelessness and imprisonment
Symptoms
- Cough for more than 3 weeks
- Coughing blood
- Fever and night sweats
- Weight loss
- Fatigue
- Latent TB has no symptoms
Diagnosis — tests and examinations
- Chest X-ray
- Sputum smear, culture and rapid molecular test (GeneXpert) with drug-resistance testing
- Interferon-gamma release assay or tuberculin skin test for latent TB
Treatment
Medicines and medical treatment
- Drug-sensitive TB: isoniazid, rifampicin, pyrazinamide and ethambutol for 2 months, then isoniazid and rifampicin for 4 months
- Newer 4-month regimens in eligible patients
- Drug-resistant TB: bedaquiline-based regimens
- Latent TB: preventive therapy (e.g. 3 months of isoniazid–rifapentine)
Operations and procedures
- Surgery rarely, for complications
Self-care, home remedies and lifestyle
- Take every dose — directly observed therapy helps
- Cover coughs and stay home until non-infectious
- Good nutrition
- Avoid alcohol while on liver-toxic drugs
Possible complications
- Spread to lymph nodes, spine, brain (meningitis), kidneys
- Lung scarring and bronchiectasis
- Drug resistance from incomplete treatment
Prevention
- BCG vaccine in infancy in high-burden countries
- Contact tracing and preventive treatment
- Ventilation and infection control
Outlook
Over 85% cure rate with complete treatment; untreated active TB kills about half of those affected.
When to see a doctor
See a doctor for a cough lasting over 3 weeks, especially with weight loss, night sweats or blood.
Sources and further reading
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