- Critical Care Associates
Shea, M.D., F.C.C.P.
What Is TB?Tuberculosis (often called TB) is an infectious disease that usually attacks the lungs, but TB can attack almost any part of the body. Tuberculosis is spread from person to person through the air. When people with TB in their lungs or throat cough, laugh, sneeze, sing, or even talk, the germs that cause TB may be spread into the air. If another person breathes in these germs there is a chance that they will become infected with tuberculosis. It is important to understand that there is a difference between being infected with TB and having TB disease. Someone who is infected with TB has the TB germs, or bacteria, in their body. The body's defenses are protecting them from the germs and they are not sick. Someone with TB disease is sick and can spread the disease to other people. A person with TB disease needs to see a doctor as soon as possible. It is not easy to become infected with tuberculosis. Usually a person has to be close to someone with TB disease for a long period of time. TB is usually spread between family members, close friends, and people who work or live together. TB is spread most easily in closed spaces over a long period of time.
Even if someone becomes infected with tuberculosis, that does not mean they will get TB disease. Most people who become infected do not develop TB disease because their body's defenses protect them.
Experts believe that about 10 million Americans are infected with TB germs. Only about 10 percent of these people will develop TB disease in their lifetime. The other 90 percent will never get sick from the TB germs or be able to spread them to other people.
Who Gets It?Anyone can get TB. People of all races and nationalities, the rich and poor, and at any age. But for many reasons, some groups of people are at higher risk to get active TB disease. The groups that are at high risk include:
What Are the Symptoms of TB?A person with a TB infection will have no symptoms. A person with TB disease may have any, all or none of the following symptoms:
How Does TB Disease Develop?There are two possible ways a person can become sick with TB disease:
The first applies to a person who may have been infected with TB for years and has been perfectly healthy. The time may come when this person suffers a change in health. The cause of this change in health may be another disease like AIDS or diabetes. Or it may be drug or alcohol abuse or a lack of health care because of homelessness. Whatever the cause, when the body's ability to protect itself is damaged, the TB infection can become TB disease. In this way, a person may become sick with TB disease months or even years after they first breathed in the TB germs. The other way TB disease develops happens much more quickly. Sometimes when a person first breathes in the TB germs the body is unable to protect itself against the disease. The germs then develop into active TB disease within weeks.
What Is the TB Skin Test?The TB skin test is a way to find out if a person has TB infection. Although there is more than one TB skin test, the preferred method of testing is to use the Mantoux test. For this test, a small amount of testing material is placed just below the top layers of skin, usually on the arm. Two to three days later a health care worker checks the arm to see if a bump has developed and measures the size of the bump. If the bump is of a certain size the test is positive and the person has TB infection. Once the doctor knows that a person has TB infection he or she may want to determine if the person has TB disease. This is done by using several other tests including a chest X-ray and a test of a person's mucus (the material that is sometimes coughed up from the lungs).
Q: Should you get a skin test each year to check on TB?
A: Only if you are at high risk for getting TB.
The advice for most people is to get a tuberculin test if you have symptoms or if you are living in close contact or have otherwise been in close contact with someone who recently came down with TB disease. (Some people get skin tests because of their jobs, in a school or hospital, for example, to make sure they will not infect others if they have TB.) However, if you fall into one or more of the high-risk categories for TB noted earlier, for example, if you are HIV-positive, or if you've never had a skin test before, or if there is no record of the last result, you should be tested. If you're not sure, ask your doctor. TB can be prevented, even if you are at risk.
What Is the Treatment for TB?Treatment for TB depends on whether a person has TB disease or only TB infection.
A person who has become infected with TB, but does not have TB disease, may be given preventive therapy. Preventive therapy aims to kill germs that are not doing any damage right now, but could break out later. If a doctor decides a person should have preventive therapy, the usual prescription is a daily doses of isoniazid (also called "INH"), an inexpensive TB medicine. The person takes INH for 9 months (up to a year for some patients), with periodic checkups to make sure the medicine is being taken as prescribed.
What if the person has TB disease? Then treatment is needed. Years ago a patient with TB disease was placed in a special hospital for months, maybe even years, and would often have surgery. Today, TB can be treated with very effective drugs. Often the patient will only have to stay a short time in the hospital and can then continue taking medication at home. Sometimes the patient will not have to stay in the hospital at all. For the first 2 weeks on adequate treatment, the person is considered contagious, and should be quarantined. After a few weeks a person can probably even return to normal activities and not have to worry about infecting others. The patient usually gets a combination of several drugs (most frequently INH plus two to three others), usually for six to nine months. The patient will probably begin to feel better only a few weeks after starting to take the drugs. It is very important, however, that the patient continue to take the medicine correctly for the full length of treatment. If the medicine is taken incorrectly or stopped the patient may become sick again and will be able to infect others with TB. If the medicine is taken incorrectly and the patient becomes sick with TB a second time, the TB may be harder to treat because it has become drug resistant. This means that the TB germs in the body are unaffected by some drugs used to treat TB.
Multi-drug resistant TB is very dangerous, so patients should be sure that they take all of their medicine correctly. Regular checkups are needed to see how treatment is progressing. Sometimes the drugs used to treat TB can cause side effects. It is important both for people undergoing preventive therapy and people being treated for TB disease to immediately let a doctor know if they begin having any unusual symptoms.
Can A TB Patient Infect Others?Yes, if they have TB disease and it is not being treated. Once treatment begins, a patient ordinarily becomes quickly noninfectious; that is, they cannot spread the disease to others. There is little danger from the TB patient who is being treated, is taking his or her medication continuously, and is responding well. The drugs usually make the patient noninfectious within 2 weeks. Germs in the air spread TB, germs put there by coughing or sneezing. Handling a patients bed sheets, books, furniture, or eating utensils does not spread infection. Brief exposure to a few TB germs rarely infects a person. It's day-after-day close contact that usually does it.
What Is Multi-Drug Resistant TB?
Multi-drug resistant tuberculosis (called MDR TB for short) is a very dangerous form of tuberculosis. Some TB germs become resistant to the effects of some TB drugs. This happens when TB disease is not properly treated. These resistant germs can then cause TB disease. The TB disease they cause is much harder to treat because the drugs do not kill the germs. MDR TB can be spread to others, just like regular TB. It is important that patients with TB disease follow their doctor's instructions for taking their TB medicine so that they will not develop MDR TB.
SummaryTB: What You Should Do. Find out if you're infected. Everyone should be skin tested at least once and know whether their test result is positive or negative. You should also be tested if there's any chance you have been infected, recently or many years ago.