Tuberculosis

Transmission, Scope, and Disease States

  • TB is a disease caused by germs that are spread from person to person through the air.

  • TB usually affects the lungs, but it can also affect other parts of the body, such as the brain, the kidneys, or the spine.

  • Not everyone infected with TB germs becomes sick. As a result, two TB-related conditions exist: latent TB infection (or inactive TB) and TB disease.

  • If not treated properly, TB disease can be fatal.

Inactive TB vs Active TB Disease (Differences)

A Person With Inactive TB

  • Has a small amount of TB germs in their body that are alive but inactive.

  • Has no symptoms and does not feel sick.

  • Cannot spread TB germs to others.

  • Usually has a positive TB blood test or TB skin test indicating TB infection.

  • Has a normal chest x-ray and a negative sputum smear.

  • Needs treatment for inactive TB to prevent active TB disease.

A Person With Active TB Disease

  • Has a large amount of active TB germs in their body.

  • Has symptoms and feels sick.

  • May spread TB germs to others.

  • Usually has a positive TB blood test or TB skin test indicating TB infection.

  • May have an abnormal chest x-ray, or positive sputum smear or culture.

  • Needs treatment for active TB disease.

If your body cannot stop TB germs from growing, you develop active TB disease.

Symptoms of Active TB Disease

  • A cough that lasts 3 weeks or longer

  • Coughing up blood or sputum

  • Weakness or fatigue

  • Chest pain

  • Fever

  • Chills

  • Night sweats

  • Loss of appetite

  • Weight loss

Testing for TB

  • TB Can Be Treated

  • Getting tested and treated for TB can protect yourself, your family and friends, and your community.

  • There are two types of tests for TB infection: the TB blood test and the TB skin test.

Positive vs Negative TB Infection Tests

  • A Positive Test For TB Infection: You have TB germs in your body. Your doctor will do other tests to determine if you have inactive TB or active TB disease. These tests may include a chest x-ray, and a test of the sputum you cough up.

  • A Negative Test For TB Infection: A negative test means you likely do not have inactive TB or active TB disease. Your doctor may do more tests if:

    • You have symptoms of active TB disease, like coughing, chest pain, fever, weight loss, or tiredness.

    • You have HIV infection.

    • Your exposure to TB germs was recent.

Medications - 6 to 9 month treatment

  • R: Rifampin - can turn bodily fluid orange/red

  • I: Isoniazid - monitor liver function and watch for signs of hepatitis, give vitamin B6

  • P: Pyrazinamide - more likely to get hepatoxicity and gout

  • E: Ethambutol - can cause optic neuritis

Tell Your Doctor if You Received a TB Vaccine

  • TB blood tests are the preferred test for people who have received the bacille Calmette-Guérin (BCG) TB vaccine. Unlike the TB skin test, TB blood tests are not affected by BCG vaccination.

  • Many people born outside of the United States have received the BCG TB vaccine.

  • BCG vaccination does not completely prevent people from getting TB.

  • A positive reaction to a TB skin test may be due to the BCG vaccine itself or due to infection with TB germs.

TB Germs, Latent TB, and Treatment Philosophy

  • TB germs can live in your body for years without causing symptoms.

  • If you have inactive TB, treating it is the best way to protect you from getting sick with active TB disease.

  • If you have been diagnosed with active TB disease, you can be treated with medicine. You will need to take and finish all of your TB medicine as directed by your doctor or nurse. This is to help you feel better and prevent other people from getting sick.

Directly Observed Therapy (DOT)

  • The best way to remember to take your medicines for active TB disease is by receiving directly observed therapy (DOT).

  • Through DOT, you will meet with a health care worker every day or several times a week, either in-person or virtually.

  • The health care worker will make sure that the TB medicines are working as they should.

BCG Vaccination Notes

  • BCG vaccination does not completely prevent TB.

  • TB tests may be affected by prior BCG vaccination (skin test more likely to be influenced than blood test).

Practical, Public Health, and Ethical Considerations

  • TB testing and treatment protect you, your family, and your community by reducing transmission.

  • Adherence to TB medication (including completing the full course) is crucial to prevent relapse and resistance.

  • DOT is used to support adherence and reduce the spread of TB.

  • Vaccination (BCG) has limitations; it does not guarantee immunity, and tests can be influenced by vaccination history.

  • Public health strategies balance individual care with community protection, aiming to minimize transmission while respecting patient dignity and privacy.

Closer Look: Key Concepts and Connections

  • Latent TB infection vs TB disease: latent infection means germs are present but inactive; disease means active replication and symptoms.

  • Transmission risk is tied to the bacillary load (inactive vs active). Active TB with coughing or sputum production is more likely to spread germs.

  • Diagnostic pathway often starts with a TB test (blood or skin), followed by imaging (chest X-ray) and microbiology (sputum smear/culture) to distinguish inactive from active disease.

  • Treatment aims: relieve symptoms, prevent progression to active disease, and prevent transmission.

  • DOT as a practical adherence strategy links clinical care to public health objectives.