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.
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, but the bacteria stop growing. If you have latent TB and later—even years later—become weak, ill, or undernourished, the TB bacteria may become active. The bacteria can then grow again and 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.
The symptoms of TB can begin anytime from 2 months to several years after you are exposed. Possible symptoms are:
Sometimes there are no symptoms.
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:
It is very important to follow your provider’s instructions regarding follow-up after your TB test. In most cases you will be asked to check back 48 to 72 hours after you had the test so it can be checked. If your test created a lump on the skin, the lump will be measured to see if it is large enough to be seen as a positive result.
A 2-step test method is used for older people because they may have a poorer immune response. If the first test is negative, the test is repeated in 7 to 10 days.
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:
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.
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.
Ask your healthcare provider the following questions:
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:
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.