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Understanding tuberculosis
Audience: patients-public, students-learners ยท Review state: published
What it is
Tuberculosis, or TB, is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It mainly attacks the lungs but can affect almost any part of the body, including the lymph nodes, bones, brain, and kidneys.
TB spreads through the air when a person with active lung TB coughs, speaks, or sneezes. Despite being preventable and curable, it remains one of the world's deadliest infectious diseases.
Latent and active TB
Most infected people never become ill: the immune system contains the bacteria, a state called latent TB, with no symptoms and no spread to others. About 5 to 10 percent of people with latent TB develop active disease over their lifetime.
The risk of activation is much higher when immunity is weakened, as with HIV, diabetes, malnutrition, or medicines that suppress the immune system.
Symptoms and diagnosis
Active lung TB typically causes a cough lasting more than three weeks, sometimes with blood, plus chest pain, fever, night sweats, weight loss, and fatigue. These symptoms deserve medical attention, especially with known exposure or in regions where TB is common.
Diagnosis uses a combination of symptom review, chest X-ray, and laboratory tests on sputum. Skin or blood tests can show whether someone has been infected, which matters for treating latent TB before it activates.
Treatment and prevention
Active TB is curable with a combination of antibiotics taken for usually six months. Completing the full course is essential: stopping early lets the bacteria survive and can produce drug-resistant TB, which is far harder to treat. Latent TB is treated with a shorter antibiotic course to prevent activation.
The BCG vaccine protects young children against severe forms of TB and is part of immunization schedules in many countries. Good ventilation, early diagnosis, and completing treatment are the pillars of control.
Limitations
General educational overview, not medical advice and not a diagnosis. TB testing and treatment belong with clinicians and public health programs; treatment must be completed as prescribed.