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Tuberculosis (TB)

Tuberculosis (TB)

Condition 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 lungs. 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 to be treated for up to 2 years.

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. A blood test also can be done to look for TB.

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 active TB after 6 months, then treatment continues for another 2 or 3 months. If the TB bacteria are resistant to several antibiotics (multidrug-resistant TB), then treatment may be needed for a year or longer.

Most of the time, one antibiotic is used to treat latent TB infection. This type of infection cannot be spread to others but can develop into active TB disease. The antibiotic usually is taken for 4 to 9 months. Or more than one antibiotic may be taken once a week for 3 months.

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 active TB.


Tuberculosis (TB) is caused by Mycobacterium tuberculosis, slow-growing bacteria that thrive in areas of the body that are rich in blood and oxygen, such as the lungs.


If you have latent tuberculosis (TB), you do not have symptoms and cannot spread the disease to others. If you have active TB, you do have symptoms and can spread the disease to others. Which specific symptoms you have will depend on whether the bacteria are in your lungs (the most common site) or in another part of your body (extrapulmonary TB).

There are other conditions with symptoms similar to TB, such as pneumonia and lung cancer.

Symptoms of active TB in the lungs

Symptoms of active TB in the lungs begin gradually and develop over a period of weeks or months. You may have one or two mild symptoms and not even know that you have the disease.

Common symptoms include:

  • A cough with thick, cloudy, and sometimes bloody mucus from the lungs (sputum) for more than 2 weeks.
  • Fever, chills, and night sweats.
  • Fatigue and weakness.
  • Loss of appetite and unexplained weight loss.
  • Shortness of breath and chest pain.

Symptoms of an active TB infection outside the lungs

Symptoms of TB outside the lungs (extrapulmonary TB) vary widely depending on which area of the body is infected. For example, back pain can be a symptom of TB in the spine, or your neck may get swollen when lymph nodes in the neck are infected.

What Happens

Tuberculosis (TB) develops when Mycobacterium tuberculosis bacteria are inhaled into the lungs. The infection usually stays in the lungs. But the bacteria can travel through the bloodstream to other parts of the body (extrapulmonary TB).

An initial (primary) infection can be so mild that you don't even know you have an infection. In a person who has a healthy immune system, the body usually fights the infection by walling off (encapsulating) the bacteria into tiny capsules called tubercles. The bacteria remain alive but cannot spread to surrounding tissues or other people. This stage is called latent TB, and most people never go beyond it.

A reaction to a tuberculin skin test is how most people find out they have latent TB. It takes about 48 hours after the test for a reaction to develop, which is usually a red bump where the needle went into the skin. Or you could have a rapid blood test that provides results in about 24 hours.

If a person's immune system becomes unable to prevent the bacteria from growing, the TB becomes active. Of people who have latent TB, 5% to 10% (1 to 2 people out of 20) will develop active TB at some point in their lives.footnote 1

Active TB in the lungs

Active TB in the lungs (pulmonary TB) is contagious. TB spreads when a person who has active disease exhales air that contains TB-causing bacteria and another person inhales the bacteria from the air. These bacteria can remain floating in the air for several hours. Coughing, sneezing, laughing, or singing releases more bacteria than breathing.

In general, after 2 weeks of treatment with antibiotics, you cannot spread active TB in the lungs to other people.

Skipping doses of medicine can delay a cure and cause a relapse. In these cases, you may need to start treatment over. Relapses usually occur within 6 to 12 months after treatment. Not taking the full course of treatment also allows antibiotic-resistant strains of the bacteria to develop, making treatment more difficult.

Without treatment, active TB can cause serious complications, such as:

  • Pockets or cavities that form in the lungs. These damaged areas may cause bleeding in the lungs or may become infected with other bacteria and form pockets of pus (abscesses).
  • A hole that forms between nearby airways in the lungs.
  • Difficulty breathing because of blocked airways.

TB can be fatal if it is not treated.

Active TB outside the lungs

Active TB in parts of the body other than the lungs (extrapulmonary TB) is not spread easily to other people. You take the same medicines that are used to treat pulmonary TB. You may need other treatments depending on where in your body the infection is growing and how severe it is.

TB in certain groups of people

Infants and children and people with HIV or AIDS who have active TB need special care.

What Increases Your Risk

People are at increased risk of infection with tuberculosis (TB) when they:

  • Have close contact (such as living in the same house) with someone who has active TB, which can be spread to others. Active TB is very contagious.
  • Are health professionals who may care for people with untreated TB.
  • Live or work in crowded conditions where they can come into contact with people who may have untreated active TB. This includes people who live or work in prisons, nursing homes, military barracks, or homeless shelters.
  • Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
  • Travel to or from regions where untreated TB is common, such as Latin America (countries in Central America, South America, and the Caribbean), Africa, Asia, Eastern Europe, and Russia.

People who have an infection that cannot spread to others (latent TB infection) are at risk of developing active TB if they:

  • Have an impaired immune system. The immune system may be weakened in older adults, newborns, women who are pregnant or have recently given birth, and people who have HIV infection, some cancers, or poorly controlled diabetes.
  • Have poor access to health care, such as homeless people, migrant farm workers, or people who abuse alcohol or drugs.
  • Take some types of medicines, such as long-term corticosteroids, biologics (used to treat rheumatoid arthritis or Crohn's disease), or medicines to prevent rejection of a transplanted organ.
  • Have a chronic lung disease caused by breathing in tiny sand or silica particles (silicosis) or celiac disease.footnote 2
  • Have had gastric bypass surgery or a gastrectomy.
  • Are 10% or more under their healthy body weight.

When To Call

Call your doctor now if you:

  • Have symptoms (such as a cough that may produce bloody mucus along with fever, fatigue, and weight loss) that could be caused by tuberculosis (TB).
  • Were in close contact with someone who has untreated active TB, which can be spread to others, or you've had lengthy close contact with someone you think has untreated active TB.
  • Have blurred vision or changes in how you see colors and are taking ethambutol for TB.
  • Notice yellowing of your skin and the whites of your eyes (jaundice), or you have belly pain and you are taking isoniazid or other medicines for TB.

Follow up with your doctor if you:

  • Recently had a TB skin test. You need to have a skin reaction measured by a health professional within 2 to 3 days after the test. This measurement is important in deciding whether you need more tests or treatment.

Exams and Tests

Diagnosing active TB in the lungs

Doctors diagnose active tuberculosis (TB) in the lungs (pulmonary TB) by using a medical history and physical exam, and by checking your symptoms (such as an ongoing cough, fatigue, fever, or night sweats). Doctors will also look at the results of a:

  • Sputum culture . Testing mucus from the lungs (sputum culture) is the best way to diagnose active TB. But a sputum culture can take 1 to 8 weeks to provide results.
  • Sputum cytology .
  • Chest X-ray . A chest X-ray usually is done if you have:
    • A positive tuberculin skin test (also called a TB skin test, PPD test, or Mantoux test).
    • Symptoms of active TB, such as a persistent cough, fatigue, fever, or night sweats.
    • An uncertain reaction to the tuberculin skin test because of a weakened immune system, or to a previous bacille Calmette-Guerin (BCG) vaccination.
  • Rapid sputum test . This test can provide results within 24 hours.

Diagnosing latent TB in the lungs

  • A tuberculin skin test will show if you have ever had a TB infection. See a picture of a tuberculin skin test.
  • Rapid blood tests help detect latent TB.footnote 3 They can help diagnose TB when results from a tuberculin skin test are uncertain. These tests also can tell if a person who has had a BCG vaccination has a TB infection. A rapid test requires only one visit to the doctor or clinic, instead of two visits as required for the tuberculin skin test. Rapid blood tests are also called interferon-gamma release assays (IGRAs).

Diagnosing TB outside the lungs

Diagnosing TB in other parts of the body (extrapulmonary TB) requires more testing. Tests include:

  • Biopsy . A sample of the affected area is taken out and sent to a lab to look for TB-causing bacteria.
  • Urine culture . This test looks for TB infection in the kidneys (renal TB).
  • Lumbar puncture . A sample of fluid around the spine is taken to look for a TB infection in the brain (TB meningitis).
  • CT scan . This test is used to diagnose TB that has spread throughout the body (miliary TB) and to detect lung cavities caused by TB.
  • MRI . This test looks for TB in the brain or the spine.

Testing for HIV infection is often done at the time of TB diagnosis. You may also have a blood test for hepatitis.

Tests during TB treatment

During treatment, a sputum culture is done once a month—or more often—to make sure that the antibiotics are working. You may have a chest X-ray at the end of treatment to use as a comparison in the future.

You may have tests to see if TB medicines are harming other parts of your body. These tests may include:

  • Liver function tests.
  • Eye tests, especially if you are taking ethambutol for TB treatment.
  • Hearing tests, especially if you are taking streptomycin for TB treatment.

Early detection

Public health officials encourage screening for people who are at risk for getting TB.

Treatment Overview

Doctors treat tuberculosis (TB) with antibiotics to kill the TB bacteria. These medicines are given to everyone who has TB, including infants, children, pregnant women, and people who have a weakened immune system.

Treatment for active tuberculosis

Health experts recommend:footnote 5

  • Using more than one medicine to prevent multidrug-resistant TB. The standard treatment begins with four medicines given for 2 months.
  • Continuing treatment for 4 to 9 months or longer if needed. The number of medicines used during this time depends on the results of sensitivity testing.
  • Using directly observed therapy (DOT). This means visits with a health professional who watches you every time you take your medicine. A cure for TB requires you to take all doses of the antibiotics. These visits ensure that people follow medicine instructions, which is helpful because of the long treatment course for TB.
  • Trying a different combination of medicines if the treatment is not working because of drug resistance (when tests show that TB-causing bacteria are still active).
  • Using different treatment programs for people infected with HIV, people infected with TB bacteria that are resistant to one or more medicines, pregnant women, and children.

Treatment for latent tuberculosis

Experts recommend one of the following:

  • Using one medicine to kill the TB bacteria and prevent active TB.
    • The standard treatment is isoniazid taken for 9 months. For people who cannot take isoniazid for 9 months, sometimes a 6-month treatment program is done.footnote 1
    • Treatment with rifampin for 4 months is another choice. This is an acceptable alternate treatment, especially for people who have been exposed to bacteria that are resistant to isoniazid.footnote 1
  • Taking two antibiotics once a week for 3 months to kill the TB bacteria.footnote 4 For this treatment, a health professional may watch you take each dose of antibiotics. Taking every dose of antibiotic helps prevent the TB bacteria from getting resistant to the antibiotics. The antibiotic combination includes isoniazid and rifapentine.

Treatment is recommended for anyone with a skin test that shows a TB infection, and is especially important for people who:

  • Are known to or are likely to be infected with HIV.
  • Have close contact with a person who has active TB.
  • Have a chest X-ray that suggests a TB infection and have not had a complete course of treatment.
  • Inject illegal drugs.
  • Have medical conditions or take medicines that weaken the immune system.

Treatment for extrapulmonary tuberculosis

Treatment for tuberculosis in parts of the body other than the lungs (extrapulmonary TB) usually is the same as for pulmonary TB. You may need other medicines or forms of treatment depending on where the infection is in the body and whether complications develop.

You may need treatment in a hospital if you have:

  • Severe symptoms.
  • TB that is resistant to multiple-drug therapy.

What to think about

If treatment is not successful, the TB infection can flare up again (relapse). People who have relapses usually have them within 6 to 12 months after treatment. Treatment for relapse is based on the severity of the disease and which medicines were used during the first treatment.


Active tuberculosis (TB) in the lungs is very contagious. The World Health Organization (WHO) estimates that one-third of the world's population is infected with the bacteria that cause TB.

To avoid getting TB:

  • Do not spend long periods of time in stuffy, enclosed rooms with anyone who has active TB until that person has been treated for at least 2 weeks.
  • Use protective measures, such as face masks, if you work in a facility that cares for people who have untreated TB. Face masks must be certified by the CDC and National Institute for Occupational Safety and Health (NIOSH).
  • If you live with someone who has active TB, help and encourage the person to follow treatment instructions.

Can the TB vaccine help?

A TB vaccine (bacille Calmette-Guerin, or BCG) is used in many countries to prevent TB. But this vaccination is almost never used in the United States because:

  • The risk of getting TB is low in the U.S.
  • The vaccine is not very effective in adults who receive it.
  • The BCG vaccine may cause a tuberculin skin test to indicate a TB infection even if a person is not infected with TB. This complicates the use of the tuberculin skin test to check people for TB.


Home treatment for tuberculosis (TB) focuses on taking the medicines correctly to reduce the risk of developing multidrug-resistant TB.

  • Keep all your medical appointments.
  • Take your medicines as prescribed.
  • Report any side effects of the medicines, especially vision problems.
  • If you plan to move during the time that you are being treated, let your doctor know so that arrangements can be made for you to continue the treatment.

Healthy eating and exercise

During treatment for TB, eat healthy foods and get enough sleep and some exercise to help your body fight the infection.

If you are losing too much weight, eat balanced meals with enough protein and calories to help you keep weight on. If you need help, ask to talk with a registered dietitian.

  • If you do not feel like eating, eat your favorite foods. Eat smaller meals several times a day instead of a few large ones.
  • Drink high-calorie protein shakes between meals. Or try nutritious drinks, such as Ensure.
  • If you feel sick to your stomach, try drinking peppermint or ginger tea.
  • Ask your doctor when it is safe for you to exercise. When you can go outside, walking is good way to get exercise. Start slowly if you have not been active. Try one 20-minute or two 10-minute walks to start. Slowly increase your time. Try to walk as often as you can.

Emotional issues

Because TB treatment takes so long, it is normal to:

  • Be embarrassed about having TB and worried that other people will find out about it.
  • Feel bad because people have to wear a mask to keep from getting infected when they are near you.
  • Feel isolated and alone because you cannot go to work, school, or public places until you can no longer infect other people.
  • Be worried about losing income or losing your job during treatment. You may also worry about paying for your medicines and doctor visits.
  • Feel guilty about the stress this is causing to family members or friends who are worried about getting TB or already have it.
  • Feel depressed.

Your doctor or health department can help you find a counselor or social worker to help you cope with your feelings. If you cannot afford counseling or treatment, there may be places that offer free or less costly help.

Protecting others

  • Don't go to work or school while you can spread TB. Sleep in a bedroom by yourself until you can no longer infect other people.
  • Open windows in a room where you must stay for a while, if the weather allows it. This can help get rid of TB bacteria from the air in the room.
  • Cover your mouth when you sneeze or cough. Until you have been on antibiotics for about 2 weeks, you can easily spread the disease to others. After coughing, dispose of the soiled tissue in a covered container. Talk with your doctor about other precautions you can take to prevent the spread of TB.


Active tuberculosis (TB)

Several antibiotics are used at the same time to treat active tuberculosis (TB) disease. For people who have multidrug-resistant TB, treatment may continue for as long as 24 months. These antibiotics are given as pills or injections.

For active TB, there are different treatment recommendations for children, pregnant women, people who have HIV and TB, and people who have drug-resistant TB.

Extrapulmonary TB

TB disease that occurs in parts of your body other than the lungs (extrapulmonary TB) usually is treated with the same medicines and for the same length of time as active TB in the lungs (pulmonary TB). But TB throughout the body (miliary TB) or TB that affects the brain or the bones and joints in children may be treated for at least 12 months.

Corticosteroid medicines also may be given in some severe cases to reduce inflammation. They may be helpful for children at risk of central nervous system problems caused by TB and for people who have conditions such as high fever, TB throughout the body (miliary TB), pericarditis, or peritonitis.

Latent TB

One antibiotic usually is used to treat latent TB infection, which cannot be spread to others but can develop into active TB disease. The antibiotic usually is taken for 4 to 9 months. Or more than one antibiotic may be taken once a week for 3 months. For this treatment, a health professional may watch you take each dose of antibiotics. Taking every dose of antibiotic helps prevent the TB bacteria from getting resistant to the antibiotics.

Medicine choices

Multiple-drug therapy to treat TB usually involves taking four antibiotics at the same time. This is the standard treatment for active TB.

Other anti-tuberculosis medicines may be used for people with multidrug-resistant TB.

What to think about

If you miss doses of medicine or you stop treatment too soon, your treatment may go on longer or you may have to start over. This can also cause the infection to get worse, or it may lead to antibiotic-resistant infections that are much harder to treat.

Taking all of the medicines is especially important for people who have an impaired immune system. They may be at an increased risk for a relapse because the original TB infection was never cured.


Surgery is rarely used to treat tuberculosis (TB). But it may be used to treat extensively drug-resistant TB (XDR-TB) or to treat complications of an infection in the lungs or another part of the body.

Surgery is used to:

  • Repair lung damage, such as serious bleeding that cannot be stopped any other way, or repeated lung infections other than TB.
  • Remove a pocket of bacteria that cannot be killed with long-term medicine treatment.

Surgery has a high success rate, but it also has a risk of complications, which may include infections other than TB and shortness of breath after surgery.

Surgery for TB outside the lungs

Surgery sometimes may be needed to remove or repair organs damaged by TB in parts of the body other than the lungs (extrapulmonary TB) or to prevent other rare complications, such as:

  • TB infection of the brain (TB meningitis). Your doctor may surgically place a tube (shunt) that drains excess fluid from the brain to prevent a buildup of pressure that can further damage the brain.
  • TB infections of the heart (TB pericarditis). Your surgeon may partially remove or repair the infected sac around the heart.
  • TB infection of the kidneys (renal TB). Your surgeon may need to either remove your infected kidney or repair the kidney or other parts of the urinary system.
  • TB infection of the joints. You may need surgery to repair damaged areas of your spine or joints (orthopedic surgery).



  1. Pasipanodya J, et al. (2015). Tuberculosis and other mycobacterial diseases. In ET Bope et al., eds., Conn's Current Therapy 2015, pp. 411–417. Philadelphia: Saunders.
  2. Ludvigsson JF, et al. (2007). Coeliac disease and risk of tuberculosis: A population based cohort study. Thorax, 62(1): 23–28.
  3. Centers for Disease Control and Prevention (2005). Guidelines for using the QuantiFERON®-TB test for diagnosing latent Mycobacterium tuberculosis infection. MMWR, 54(RR-15): 49–55.
  4. Centers for Disease Control and Prevention (2018). Update of recommendations for use of once-weekly isoniazid-rifapentine regimen to treat latent Mycobacterium tuberculosis infection. MMWR, 67: 723–726. DOI: Accessed September 17, 2018.
  5. American Thoracic Society, Centers for Disease Control and Prevention, Infectious Diseases Society of America (2003). Treatment of tuberculosis. American Journal of Respiratory and Critical Care Medicine, 167(4): 603–662.


Current as of: February 9, 2022

Author: Healthwise Staff
Medical Review:
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
R. Steven Tharratt MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
W. David Colby IV MSc, MD, FRCPC - Infectious Disease

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