Tuberculosis (TB) is caused by a bacterium called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain. Not everyone infected with TB bacteria becomes sick. As a result, two TB-related conditions exist: latent TB infection (LTBI) and TB disease. If not treated properly, TB disease can be fatal.
TB bacteria spread through the air from one person to another. When a person with TB disease of the lungs or throat coughs, speaks, or sings, TB bacteria can get into the air. People nearby may breathe in these bacteria and become infected.
TB is NOT spread by
When a person breathes in TB bacteria, the bacteria can settle in the lungs and begin to grow. From there, they can move through the blood to other parts of the body, such as the kidney, spine, and brain.
TB disease in the lungs or throat can be infectious. This means that the bacteria can spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious.
People with TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, and coworkers or schoolmates.
Symptoms of TB disease depend on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs (pulmonary TB). TB disease in the lungs may cause symptoms such as
Other symptoms of TB disease are
Symptoms of TB disease in other parts of the body depend on the area affected.
People who have latent TB infection
Some people develop TB disease soon after becoming infected (within weeks) before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason.
Overall, about 5 to 10% of infected persons who do not receive treatment for latent TB infection will develop TB disease at some time in their lives. For persons whose immune systems are weak, especially those with HIV infection, the risk of developing TB disease is much higher than for persons with normal immune systems.
Generally, persons at high risk for developing TB disease fall into two categories:
This includes:
Symptoms of TB disease in other parts of the body depend on the area affected.
People who have latent TB infection
Babies and young children often have weak immune systems. Other people can have weak immune systems, too, especially people with any of these conditions:
You may have been exposed to TB bacteria if you spent time near someone with TB disease. The TB bacteria are put into the air when a person with active TB disease of the lungs or throat coughs, sneezes, speaks, or sings. You cannot get TB from
If you think you have been exposed to someone with TB disease, you should contact your doctor or local health department about getting a TB skin test or a special TB blood test. Be sure to tell the doctor or nurse when you spent time with the person who has TB disease.
It is important to know that a person who is exposed to TB bacteria is not able to spread the bacteria to other people right away. Only persons with active TB disease can spread TB bacteria to others. Before you would be able to spread TB to others, you would have to breathe in TB bacteria and become infected. Then the active bacteria would have to multiply in your body and cause active TB disease. At this point, you could possibly spread TB bacteria to others. People with TB disease are most likely to spread the bacteria to people they spend time with every day, such as family members, friends, coworkers, or schoolmates.
Some people develop TB disease soon (within weeks) after becoming infected, before their immune system can fight the TB bacteria. Other people may get sick years later, when their immune system becomes weak for another reason. Many people with TB infection never develop TB disease.
There are two types of tests for TB infection: the TB skin test and the TB blood test. A person’s health care provider should choose which TB test to use. Factors in selecting which test to use include the reason for testing, test availability, and cost. Generally, it is not recommended to test a person with both a TB skin test and a TB blood test.
Administering the TB skin test
The TB skin test is also called the Mantoux tuberculin skin test (TST). A TB skin test requires two visits with a health care provider.
On the first visit the test is placed; on the second visit the health care provider reads the test.
Reading the result of a TB skin test
Positive skin test: This means the person’s body was infected with TB bacteria. Additional tests are needed to determine if the person has latent TB infection or TB disease.
Negative skin test: This means the person’s body did not react to the test, and that latent TB infection or TB disease is not likely.
There is no problem in repeating a TB skin test. If repeated, the additional test should be placed in a different location on the body (e.g., other arm).
The TB skin test is the preferred TB test for children under the age of five.
TB blood tests are also called interferon-gamma release assays or IGRAs. Two TB blood tests are approved by the U.S. Food and Drug Administration (FDA) and are available in the United States: the QuantiFERON®-TB Gold Plus (QFT-Plus) and the T-SPOT®.TB test (T-Spot).
A health care provider will draw a patient’s blood and send it to a laboratory for analysis and results.
Positive TB blood test: This means that the person has been infected with TB bacteria. Additional tests are needed to determine if the person has latent TB infection or TB disease.
Negative TB blood test: This means that the person’s blood did not react to the test and that latent TB infection or TB disease is not likely.
TB blood tests are the preferred TB test for:
Many people who have latent TB infection never develop TB disease. But some people who have latent TB infection are more likely to develop TB disease than others. Those at high risk for developing TB disease include:
If you have latent TB infection and you are in one of these high-risk groups, you should take medicine to keep from developing TB disease. There are several treatment options for latent TB infection. You and your health care provider must decide which treatment is best for you. If you take your medicine as instructed, it can keep you from developing TB disease. Because there are less bacteria, treatment for latent TB infection is much easier than treatment for TB disease. A person with TB disease has a large amount of TB bacteria in the body. Several drugs are needed to treat TB disease.
Bacille Calmette-Guérin (BCG) is a vaccine for tuberculosis (TB) disease. This vaccine is widely used in Pakistan. It is often given to infants and small children.
Tuberculosis is a serious health threat, especially for people living with HIV. People living with HIV are more likely than others to become sick with TB. Worldwide, TB is one of the leading causes of death among people living with HIV.
Without treatment, as with other opportunistic infections, HIV and TB can work together to shorten lifespan.
People infected with HIV who also have either latent TB infection or TB disease can be effectively treated. The first step is to ensure that people living with HIV are tested for TB infection. If found to have TB infection, further tests are needed to rule out TB disease. The next step is to start treatment for latent TB infection or TB disease based on test results.
Untreated latent TB infection can quickly progress to TB disease in people living with HIV since the immune system is already weakened. And without treatment, TB disease can progress from sickness to death.
Fortunately, there are a number of treatment options for people living with HIV who also have either latent TB infection or TB disease.
Diabetes is a chronic (long-lasting) disease that affects how the body turns food into energy.
Tuberculosis (TB) is a serious health threat, especially for people living with diabetes. Two TB-related conditions exist: latent TB infection and TB disease. People with latent TB infection are not sick because the body is able to fight the bacteria to stop them from growing. People with TB disease are sick and have active TB because the body cannot stop the bacteria from growing. People living with diabetes who are also infected with TB are more likely to develop TB disease and become sick with TB.
Someone with untreated latent TB infection and diabetes is more likely to develop TB disease than someone without diabetes. Without proper treatment, diabetes and TB can increase health complications.
Untreated latent TB infection can progress to TB disease. TB disease, without treatment, can progress from sickness to death.
Fortunately, treatment options are available for people with diabetes who also have either latent TB infection or TB disease. If a person is diagnosed with TB infection, further testing is required to rule out TB disease. People with either latent TB infection or TB disease can be effectively treated.
Before beginning treatment for TB disease or for latent TB infection, TB patients should talk to their doctor about any other medication they are taking, including medicine for diabetes. Some medications used to treat TB might interact with medicine used treat diabetes.
Tuberculosis (TB) is a disease caused by bacteria 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. In most cases, TB is treatable and curable; however, people with TB can die if they do not get proper treatment. Sometimes drug-resistant TB occurs when bacteria become resistant to the drugs used to treat TB. This means that the drug can no longer kill the TB bacteria.
Drug-resistant TB (DR TB) is spread the same way that drug-susceptible TB is spread. TB is spread through the air from one person to another. The TB bacteria are put into the air when a person with TB disease of the lungs or throat coughs, sneezes, speaks, or sings. People nearby may breathe in these bacteria and become infected.
Drug-resistant TB can occur when the drugs used to treat TB are misused or mismanaged. Examples of misuse or mismanagement include
Drug-resistant TB is more common in people who
Multidrug-resistant TB (MDR TB) is caused by TB bacteria that are resistant to at least isoniazid and rifampin, the two most potent TB drugs. These drugs are used to treat all persons with TB disease.
TB experts should be consulted in the treatment of MDR TB.
Pre-Extensively Drug-resistant TB (pre-XDR TB) is a type of MDR TB caused by TB bacteria that are resistant to isoniazid, rifampin, and a fluroquinolone OR by TB bacteria that are resistant to isoniazid, rifampin, and a second-line injectable (amikacin, capreomycin, and kanamycin).
Extensively drug-resistant TB (XDR TB) is a rare type of MDR TB caused by TB bacteria that are resistant to isoniazid and rifampin, a fluroquinolone, and a second-line injectable (amikacin, capreomycin, and kanamycin) OR by TB bacteria that are resistant to isoniazid, rifampin, a fluroquinolone, and bedaquiline or linezolid.
Because XDR TB is resistant to the most potent TB drugs, patients are left with treatment options that are much less effective.
XDR TB is of special concern for people with HIV infection or other conditions that can weaken the immune system. These people are more likely to develop TB disease once they are infected, and also have a higher risk of death once they develop TB.
The most important way to prevent the spread of drug-resistant TB is to take all TB drugs exactly as prescribed by the health care provider. No doses should be missed and treatment should not be stopped early. People receiving treatment for TB disease should tell their health care provider if they are having trouble taking the drugs.
Health care providers can help prevent drug-resistant TB by quickly diagnosing cases, following recommended treatment guidelines, monitoring patients’ response to treatment, and making sure therapy is completed.
Another way to prevent getting drug-resistant TB is to avoid exposure to known drug-resistant TB patients in closed or crowded places such as hospitals, prisons, or homeless shelters. People who work in hospitals or health-care settings where TB patients are likely to be seen should consult infection control or occupational health experts.
Drug-resistant TB is caused by TB bacteria that are resistant to at least one first-line anti-TB drug. Multidrug-resistant TB (MDR TB) is resistant to more than one anti-TB drug and at least isoniazid (INH) and rifampin (RIF).
Extensively drug-resistant TB (XDR TB) is a rare type of MDR TB that is resistant to isoniazid and rifampin, plus any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin).
Treating and curing drug-resistant TB is complicated. Inappropriate management can have life-threatening results. Drug-resistant TB should be managed by or in close consultation with an expert in the disease.