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Tuberculosis (TB)


Topic Overview

What is tuberculosis?

Tuberculosis (TB) is an infection caused by slow-growing bacteria that grow best in areas of the body that have lots of blood and oxygen. That's why it is most often found in the lungsClick here to see an illustration.. This is called pulmonary TB. But TB can also spread to other parts of the body, which is called extrapulmonary TB. Treatment is often a success, but it is a long process. It usually takes about 6 to 9 months to treat TB. But some TB infections need up to 2 years to treat.

Tuberculosis is either latent or active.

  • Latent TB means that you have the TB bacteria in your body, but your body's defenses (immune system) are keeping it from turning into active TB. This means that you don't have any symptoms of TB right now and can't spread the disease to others. If you have latent TB, it can become active TB.
  • Active TB means that the TB bacteria are growing and causing symptoms. If your lungs are infected with active TB, it is easy to spread the disease to others.

How is TB spread to others?

Pulmonary TB (in the lungs) is contagious. It spreads when a person who has active TB breathes out air that has the TB bacteria in it and then another person breathes in the bacteria from the air. An infected person releases even more bacteria when he or she does things like cough or laugh.

If TB is only in other parts of the body (extrapulmonary TB), it does not spread easily to others.

Who is most at risk for TB?

Some people are more likely than others to get TB. This includes people who:

  • Have HIV or another illness that weakens the immune system.
  • Have close contact with someone who has active TB, such as living in the same house as someone who is infected with TB.
  • Care for a patient who has active TB, such as doctors or nurses.
  • Live or work in crowded places, such as prisons, nursing homes, or homeless shelters, where other people may have active TB.
  • Have poor access to health care, such as homeless people and migrant farm workers.
  • Abuse drugs or alcohol.
  • Travel to or were born in places where untreated TB is common, such as Latin America, Africa, Asia, Eastern Europe, and Russia.

It is important for people who are at a high risk for getting TB to get tested once or twice every year.

What are the symptoms?

Most of the time when people are first infected with TB, the disease is so mild that they don't even know they have it. People with latent TB don't have symptoms unless the disease becomes active.

Symptoms of active TB may include:

  • A cough that brings up thick, cloudy, and sometimes bloody mucus from the lungs (called sputum) for more than 2 weeks.
  • Tiredness and weight loss.
  • Night sweats and a fever.
  • A rapid heartbeat.
  • Swelling in the neck (when lymph nodes in the neck are infected).
  • Shortness of breath and chest pain (in rare cases).

How is TB diagnosed?

Doctors usually find latent TB by doing a tuberculin skin test. During the skin test, a doctor or nurse will inject TB antigens under your skin. If you have TB bacteria in your body, within 2 days you will get a red bump where the needle went into your skin. The test can't tell when you became infected with TB or if it can be spread to others.

To find pulmonary TB, doctors test a sample of mucus from the lungs (sputum) to see if there are TB bacteria in it. Doctors sometimes do other tests on sputum and blood or take a chest X-ray to help find pulmonary TB.

To find extrapulmonary TB, doctors can take a sample of tissue (biopsy) to test. Or you might get a CT scan or an MRI so the doctor can see pictures of the inside of your body.

How is it treated?

Most of the time, doctors combine four antibiotics to treat active TB. It's important to take the medicine for active TB for at least 6 months. Almost all people are cured if they take their medicine just like their doctors say to take it. If tests still show an active TB infection after 6 months, then treatment continues for another 2 or 3 months.

People with latent TB may be treated with one antibiotic that they take daily for 9 months or with a combination of antibiotics that they take once a week for 12 weeks while being watched by a health professional. Making sure every dose is taken reduces their risk for getting active TB.

If you miss doses of your medicine, or if you stop taking your medicine too soon, your treatment may fail or have to go on longer. You may have to start your treatment over again. This can also cause the infection to get worse or may lead to an infection that is resistant to antibiotics. This is much harder to treat.

TB can only be cured if you take all the doses of your medicine. A doctor or nurse may have to watch you take it to make sure that you never miss a dose and that you take it the proper way. You may have to go to the doctor's office every day. Or a nurse may come to your home or work. This is called direct observational treatment. It helps people follow all of the instructions and keep up with their treatment, which can be complex and take a long time. Cure rates for TB have greatly improved because of this type of treatment.

If active TB is not treated, it can damage your lungs or other organs and can be deadly. You can also spread TB by not treating an active TB infection.

Frequently Asked Questions

Learning about tuberculosis (TB):

Being diagnosed:

Getting treatment:

Ongoing concerns:

Living with tuberculosis:

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