Tuberculosis

Tuberculosis (often called TB) is an infectious disease that usually attacks the lungs, but 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 spread throughout the air. If another person breathes in these germs there is a chance that they will become infected with tuberculosis. Repeated contact is usually required for infection.
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. This is referred to as latent TBI.
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. This is referred to as active TBII.
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. However, transmission in an airplane, although rare, has been documented.
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. Most active cases of TB disease result from activating old infection in people with impaired immune systems.
Someone in the world is newly infected with TB bacilli every second and one-third of the world’s population is currently infected with TB.1 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.2
TB is an increasing and major world wide problem, especially in Africa where the spread has been facilitated by AIDS. It is estimated that nearly 1 billion people will become newly infected, over 150 million will become sick, and 36 million will die worldwide between now and 2020 – if control is not strengthened further. Each year there are more than 8.8 million cases and close to 1.6 million deaths attributed to TB.3
Anyone can get TB. However, some groups are at higher risk to get active TB disease. The groups that are at high risk include:
People with HIV infection (the AIDS virus)
People in close contact with those known to be infectious with TB
People with medical conditions that make the body less able to protect itself from disease (for example: diabetes, the dust disease silicosis, or people undergoing treatment with drugs that can suppress the immune system, such as long-term use of corticosteroids)
Foreign-born people from countries with high TB rates
People who work in or are residents of long-term care facilities (nursing homes, prisons, some hospitals)
Health care workers and others such as prison guards
People who are malnourished
Alcoholics, IV drug users and people who are homeless
A person with TB infection will have no symptoms. A person with active TB disease may have any, all or none of the following symptoms:
A persistent cough
Constant fatigue
Weight loss
Loss of appetite
Fever
Coughing up blood
Night sweats
These symptoms can also occur with other diseases so it is important to see a doctor and to let the doctor determine if you have TB.
It is also important to remember that a person with TB disease may feel perfectly healthy or may only have a cough from time to time. If you think you have been exposed to TB, get a TB skin test.
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 may be due to a variety of reasons such as another disease like AIDS or diabetes, drug or alcohol abuse, lack of access to health care and homelessness.
Whatever the cause may be, when the body's ability to protect itself is compromised, TB infection can become active 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.
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.4For 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. The significance of the size of the bump is determined in conjunction with risk factors for TB.Once the doctor knows that a person has TB infection he or she will 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).
Treatment for TB depends on whether a person has active TB disease or only TB infection.5
A person who has become infected with TB, but does not have active TB disease, may be given preventive therapy. Preventive therapy aims to kill germs that are not doing any damage right now, but could so do.
If a doctor decides a person should receive preventive therapy, the usual prescription is a daily dose of isoniazid (also called "INH"); an inexpensive TB medicine. The person takes INH for nine months (up to a year for some patients), with periodic checkups to make sure the medicine is being taken as prescribed.
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. 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 including rifampin, pyrazinamide and ethambutol). 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. As a result, public health authorities recommend Directly Observed Therapy (DOT), in which a health care worker insures that the patient takes his/her medicine.
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.
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.
Once treatment begins, a patient ordinarily quickly becomes 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 weeks.
TB is spread by germs in the air, germs put there by coughing or sneezing. Handling a patient’s bed sheets, books, furniture, or eating utensils does not spread infection.
Brief exposure to a source of TB rarely infects a person. It's day-after-day close contact that usually does it.
A negative reaction usually means that you are not infected and no treatment is needed. However, if you have TB symptoms your doctor must continue to look for the cause. Sometimes, when a person has only recently been infected, or when his or her immune system isn't working properly, the test may be falsely negative.