Tuberculosis (TB)

| What is tuberculosis? | Is tuberculosis an infectious and contagious disease that can be treated? | How does a person get TB? | What happens to the body when a person gets TB? | How common is TB and who gets it? | How can I get tested for TB? | How do patients with tuberculosis feel? | How does a doctor diagnose tuberculosis? | How is tuberculosis treated? | What are the side effects of medicines for TB? | Why do I need to take TB medicine regularly? | How can I keep from spreading TB?
 | What is drug-resistant tuberculosis? Can people with drug-resistant tuberculosis be treated? | Can people be vaccinated against tuberculosis? | What is the difference between tuberculosis disease and latent tuberculosis infection? | If I have latent TB infection, how can I keep from developing active TB disease? | What if I have HIV infection? | What's in the future for TB? | What is directly observed therapy? | Tuberculosis At A Glance |

What is tuberculosis?

Tuberculosis (also known as “TB”) is an infectious disease caused by germs that are spread from person to person through the air.

The bacteria are put into the air when a person with active TB disease of the lungs or throat coughs or sneezes.  People nearby may breathe in these bacteria and become infected.   A person with tuberculosis can die if they do not get treatment.

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 in the lungs or throat can be infectious. This means that the bacteria can be spread to other people. TB in other parts of the body, such as the kidney or spine, is usually not infectious.

People with active TB disease are most likely to spread it to people they spend time with every day. This includes family members, friends, and coworkers.

However, not everyone infected with TB bacteria becomes sick. People who are not sick have what is called latent TB infection. People who have latent TB infection do not feel sick, do not have any symptoms, and cannot spread TB to others. But, some people with latent TB infection go on to get TB disease.

People with active TB disease can be treated and cured if they seek medical help. Even better, people with latent TB infection can take medicine so that they will not develop active TB disease.

Many years ago, this disease used to be called "Consumption" because without effective treatment, these patients often would waste away. Today, of course, tuberculosis usually can be treated successfully with antibiotics.

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Is tuberculosis an infectious and contagious disease that can be treated?

Tuberculosis is an infectious disease caused by germs that are spread from person to person through the air.

Tuberculosis disease can be cured by taking several drugs for 6 to 12 months. It is very important that people who have tuberculosis disease finish the medicine, and take the drugs exactly as prescribed. If they stop taking the drugs too soon, they can become sick again; if they do not take the drugs correctly, the germs that are still alive may become resistant to those drugs.

Tuberculosis that is resistant to drugs is harder and more expensive to treat.

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How does a person get TB?

A person can become infected with tuberculosis bacteria when he or she inhales minute particles of infected sputum from the air.

The bacteria get into the air when someone who has a tuberculosis lung infection coughs, sneezes, shouts, or spits (which is common in some cultures). People who are nearby can then possibly breathe the bacteria into their lungs.

You don't get TB by just touching the clothes or shaking the hands of someone who is infected. Tuberculosis is spread (transmitted) primarily from person to person during close contact by breathing infected air.

There is a form of tuberculosis, however, that is transmitted by drinking unpasteurized milk.  Related bacteria, called Mycobacterium bovis, cause this form of TB. It previously was a major cause of TB in children, but rarely causes TB now since most milk is pasteurized (a heating process that kills the bacteria).

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What happens to the body when a person gets TB?

When the inhaled tuberculosis bacteria enter the lungs, they can multiply, causing a local lung infection (pneumonia). The local lymph nodes associated with the lungs may also become involved. In addition, TB can spread to other parts of the body. The body's immune (defense) system, however, can fight off the infection and stop the bacteria from spreading. The immune system does so ultimately by forming scar tissue around the TB bacteria and isolating it from the rest of the body.

If the body is able to form scar tissue (fibrosis) around the TB bacteria, then the infection is contained in an inactive state. Such an individual typically has no symptoms and cannot spread TB to other people. The scar tissue and lymph nodes may eventually harden, like stone. (That is, these scars and nodes can calcify.)

Sometimes, however, the body's immune system becomes weakened and the TB bacteria break through the scar tissue.

For example, the immune system can be weakened by old age, the development of another infection or a cancer, or certain medications such as cortisone or anti-cancer drugs. The break through of bacteria can result in a recurrence of the pneumonia and a spread of TB to elsewhere in the body. The kidneys, bone, and lining of the brain and spinal cord are the most common sites affected by the spread of TB beyond the lungs.

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How common is TB and who gets it?

Over 8 million new cases of TB occur each year worldwide. In the United States, it is estimated that 10-15 million people are infected with the TB bacteria and 22,000 new cases of TB occur each year.

Anyone can get TB, but certain people are at higher risk including:

• Those who live with individuals who have active TB infection

• Poor or homeless people

• Foreign-born persons from countries that have a high occurrence of TB

• Nursing home residents and prison inmates

• Alcoholics and intravenous drug users

• Those with diabetes, certain cancers, and HIV infection (the AIDS virus)

• Health care workers

• There is no strong evidence for a genetically determined (inherited) susceptibility for TB.

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How can I get tested for TB?

You should get tested for TB if

• You have spent time with a person known to have active TB disease or suspected to have active TB disease; or

• You have HIV infection or another condition that puts you at high risk for active TB disease; or

• You think you might have active TB disease; or

• You being to a country where active TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia); or

• You inject illegal drugs.

The TB skin test may be used to find out if you have TB infection.   A small amount of testing fluid (called tuberculin or PPD) is injected just under the skin on the under side of the forearm. After 2 or 3 days, you may have a swelling where the tuberculin was injected. This swelling will be measured for a positive or negative reaction . A positive reaction usually means that you have been infected by someone with active TB disease.

If you have recently spent time with and been exposed to someone with active TB disease, your TB skin test reaction may not be positive yet. You may need a second skin test 10 to 12 weeks after the last time you spent time with the person. This is because it can take several weeks after infection for your immune system to react to the TB skin test. If your reaction to the second test is negative, you probably do not have latent TB infection.

QuantiFERON®-TB Gold (QFT) is a blood test used to find out if you are infected with TB bacteria. The QFT measures the response to TB proteins when they are mixed with a small amount of blood.  Currently, not many hospital offer the QFT.  If QFT is offered, only one visit is required, at which time your blood is drawn for the test.

If you have a positive reaction to the TB skin test or the QFT, your doctor or may do other tests to see if you have active TB disease. These tests usually include a chest x-ray and a test of the phlegm you cough up. Because the TB bacteria may be found somewhere other than your lungs, your doctor may check your blood or urine, or do other tests. If you have active TB disease, you will need to take medicine to cure the disease.

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How do patients with tuberculosis feel?

As previously mentioned, TB infection usually occurs initially in the upper part (lobe) of the lungs. The body's immune system, however, can stop the bacteria from continuing to reproduce.

Thus, the immune system can make the lung infection inactive (dormant). On the other hand, if the body's immune system cannot contain the TB bacteria, the bacteria will reproduce (become active or reactivate) in the lungs and spread elsewhere in the body.

It may take many months from the time the infection initially gets into the lungs until symptoms develop. The usual symptoms that occur with an active TB infection are a generalized tiredness or weakness, weight loss, fever, and night sweats. If the infection in the lung worsens, then further symptoms can include coughing, chest pain, coughing up of sputum (material from the lungs) and/or blood, and shortness of breath. If the infection spreads beyond the lungs, the symptoms will depend upon the organs involved.

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How does a doctor diagnose tuberculosis?     <more.....>

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