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What is tuberculosis?

Tuberculosis (TB) is an infectious disease that usually develops slowly and can lead to ill health for a long time. If it is not treated it can cause death.

How does it occur?

TB is caused by a type of bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs. They can destroy parts of the lungs, making it hard to breathe. The bacteria can spread to and damage other parts of the body, especially the brain, kidneys, bones, and joints. The lymph nodes can also become infected.

Most people who are infected with TB bacteria do not develop active TB; that is, they do not become sick and usually do not infect others. Their body defenses control the infection by building a wall around the bacteria. This is called latent TB. The walling-in process does not kill the bacteria. If you have latent TB and later--even years later--become weak, ill, or undernourished, you may start having active TB.

If you are exposed to a large amount of TB bacteria, you may become ill with active TB soon after you are first infected with the bacteria.

TB is very contagious. It is spread mainly through the air. A person who has active TB can spread the disease by spraying droplets infected with the bacteria into the air by coughing, sneezing, speaking, singing, or laughing.

What are the symptoms?

The symptoms of TB can begin anytime from 2 months to several years after you are exposed. Possible symptoms are:

  • tiredness
  • weight loss and loss of appetite
  • fever
  • sweating at night
  • joint pain
  • a cough that starts out dry but later produces sputum.

Sometimes there are no symptoms.

How is it diagnosed?

Your healthcare provider will ask about your symptoms and give you a physical exam. You will need to have a tuberculin skin test, chest X-ray, and sputum culture:

  • Tuberculin (PPD) skin test: Your healthcare provider will inject a substance called tuberculin, or PPD, beneath your skin. If you are infected with TB, a lump will form where this shot was given within 3 days. This reaction is called a positive tuberculin test. It means that TB bacteria have invaded your body. It does not necessarily mean you have active, infectious TB. In fact, most people with positive tuberculin tests do not have active TB. If your PPD test is positive, close family members should also have the test.
  • Chest X-ray: If you have breathed in TB bacteria but have fought off the infection, your lungs may not be damaged and your chest X-ray may be normal. However, if you have an active infection and bacteria have attacked your lungs, the infection will show on a chest X-ray.
  • Sputum exam and culture: Sputum is material coughed up from the lungs. It may include mucus and blood. A sample of sputum coughed up from the lungs can be viewed with a microscope to see if there are TB bacteria in the sputum. A culture test can be done to see if TB bacteria can be grown from the sputum. If TB bacteria do grow, you have TB. It may take up to 6 to 8 weeks for a sputum culture to give definite results.

How is it treated?

If you have active TB, you will be treated with medicines at home or in the hospital. You will probably be given several medicines, which you will need to take for several months. Possible medicines include:

  • isoniazid (INH)
  • rifampin
  • pyrazinamide
  • ethambutol.

You usually have to take more than one medicine because one alone may not kill all the TB bacteria.

The medicines have many side effects and can upset the stomach or cause liver problems. You will need to have blood tests while you are taking these drugs.

If your TB skin test is positive but you do not have active TB, you will probably still need some treatment with medicine to kill the TB bacteria and prevent an active infection. This is especially important if you have other medical problems, such as diabetes, that make it harder for you to fight infections.

Tuberculosis has become a more common disease. New strains of the TB bacteria sometimes cannot be killed by the drugs listed above and new treatments must be found. These new strains are called resistant TB, meaning that the TB bacteria have become resistant to the usual medicines.

Quarantine is a very old way to prevent disease and it is still used sometimes. It means that someone who is infected is kept separate from uninfected people. Sometimes people who have just been diagnosed with active TB have to be quarantined. Because TB is so contagious and because the bacteria tend to be in every cough, sneeze, and breath, you may be quarantined for a few days or a couple weeks until your healthcare providers believe you can no longer infect others. Quarantine is especially important if you have an active TB infection with one of the resistant types of bacteria.

TB bacteria are more likely to become resistant if people who have TB do not take their TB medicines on the recommended schedule. To try to prevent the development of resistant strains, take your medicines exactly as your healthcare provider has directed.

How long will the effects last?

Almost everyone who is properly treated for TB is cured. The main reason that treatments do not work sometimes is that people have not taken their medicines properly.

How can I take care of myself?

Ask your healthcare provider the following questions:

  • May I continue doing everything I am used to doing; for example, exercising and cooking for my family? May I continue to work?
  • What kind of diet is best?
  • How long after I start taking the medicines am I still contagious?
  • If I am pregnant or breast-feeding, will the TB bacteria infect my child? Will the medicines I am taking hurt my child?
  • How can I help keep my family and friends from getting infected?
  • What are the side effects of the medicines?
  • Are there any medicines I should avoid while taking the TB medicines?
  • Can I drink alcohol while I am taking the TB medicines?
  • What tests should I have before I begin the TB medicines (for example, liver function test)? How often will I need to repeat the tests while I am taking the medicines?

What can be done to help prevent tuberculosis?

TB can be prevented. To help keep the disease from spreading, people infected with TB bacteria must be diagnosed early.

If you have active TB, you can help prevent spread of the disease by following these guidelines:

  • Start treatment with antibiotics as early as possible. Take all of your TB medicine exactly as prescribed.
  • Put used tissues in a plastic bag and seal the bag before you throw it in the garbage.
  • Cover your mouth and nose when you cough, sneeze, or laugh.
  • Wash your hands after sneezing or coughing or any time your hands are around your mouth or nose.

If you have latent TB, your provider may prescribe isoniazid to prevent an active infection. If you cannot take preventive medicine, make sure you keep your follow-up appointments with your provider. Checkups will find TB that is becoming active. The active TB can then be treated at an early stage before much, if any, damage is done.

If you work in a prison, hospital, or long-term care facility, or if you work with groups of people that have a high rate of TB, you should be tested for TB regularly. Check with your provider to find out how often you should be tested. You should also ask how often you should be checked for TB if you have a medical problem that weakens your immune system, such as diabetes or HIV infection.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

HIA File infd4540.htm Release 13/2010

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