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- What is tuberculosis?
TB, or tuberculosis, is a disease caused by bacteria caused
Mycobacterium tuberculosis. It is spread from person to
person through the air. TB usually affects the lungs. TB
can also affect other parts of the body, such as the brain,
kidneys or the spine.
TB bacteria become active if the immune system can't
stop them from growing. The active bacteria begin to
multiply in the body and cause TB disease. Some people
develop TB disease soon after becoming infected, before
their immune system can fight the TB bacteria. Other
people may get sick later, when their immune system
becomes weak for some reason.
Babies and young children often have weak immune
systems. People infected with HIV, the virus that
causes AIDS, have very weak immune systems. Other
people can have weak immune systems, too, especially
people with any of these conditions:
- substance abuse, diabetes mellitus, silicosis, cancer
of the head or neck, leukemia or Hodgkin's disease, severe kidney disease, low body weight, certain
medical treatments (such as corticosteroid treatment or
- What are the symptoms of tuberculosis?
Symptoms of TB depend on where in the body the TB bacteria
are growing. TB bacteria usually grow in the lungs. TB in
the lungs may cause:
Other symptoms of TB disease are:
- a bad cough that lasts longer than 2 weeks
- pain in
- coughing up blood or sputum (phlegm from
deep inside the lungs)
- weakness or fatigue
- weight loss
- no appetite
- sweating at night
- How is TB spread?
TB is spread through the air from one person to another. The
bacteria are put into the air when a person with TB disease
of the lungs or throat coughs or sneezes. People nearby may
breathe in these bacteria and become infected.
When a person breathes in TB bacteria, the bacteria can
settle in the lungs and begin to grow. From there, they
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 TB disease are most likely to spread it to
people they spend time with every day. This includes
family members, friends, and coworkers.
- How Is TB disease treated?
People with TB disease, need to take several different drugs
for at least six months, even if they start feeling well
after only a few weeks of treatment. . This is because there
are many bacteria to be killed. Taking several drugs as
prescribed will do a better job of killing all of the
bacteria and preventing them from becoming resistant to the
drugs. TB disease can almost always be cured with medicine.
People with TB of the lungs or throat, are probably
infectious. They need to stay home from work or school
so that they don't spread TB bacteria to other people.
After taking their medicine for a few weeks, they will
feel better and may no longer be infectious to others.
Their doctor or nurse will tell them when they can
return to work or school.
Having TB should not stop a person from leading a
normal life. When they are no longer infectious or
feeling sick, they can do the same things they did
before they had TB. The medicine that they are taking
should not affect their strength, sexual function, or
ability to work. If they take their medicine as their
doctor or nurse tells them, the medicine will kill all
the TB bacteria. This will keep them from becoming sick
- What is Directly Observed Therapy (DOT)?
Directly observed therapy (DOT) is a way that patients are
administered their medication. Patients on DOT will meet
with a health care worker every day or several times a week.
They will meet at a mutually agreeable place. This can be
the TB clinic, at home or work, or any other convenient
DOT helps in several ways. The health care worker can
help persons remember to take their medicine and
complete their treatment. This means they will get
well as soon as possible. With DOT, they may need to
take medicine only 2 or 3 times each week instead of
every day. The health care worker will make sure that
the medicine is working as it should. This person will
also watch for side effects and answer questions you
have about TB.
Even if a person is not getting DOT, they must be
checked at different times to make sure everything is
going well. They should see their doctor or nurse
regularly while they are medicine. This will continue
until they are cured.
- What Is Multidrug-Resistant TB (MDR TB)?
When TB patients do not take their medicine as prescribed,
the TB bacteria may become resistant to a certain drug. This
means that the drug can no longer kill the bacteria.
Drug resistance is more common in people who:
- have spent time with someone with drug-resistant TB
- do not take their medicine regularly
- do not
take all of their prescribed medicine
- develop TB
disease again, after having taken TB medicine in the
- come from areas where drug-resistant TB is common
(Southeast Asia, Latin America, Haiti, and the
Sometimes the bacteria become resistant to more than
one drug. This is called multidrug-resistant TB, or MDR
TB. This is a very serious problem. People with MDR TB
disease must be treated with special drugs. These drugs
are not as good as the usual drugs for TB and they may
cause more side effects. Also, some people with MDR TB
disease must see a TB expert who can closely observe
their treatment to make sure it is working.
People who have spent time with someone sick with MDR
TB disease can become infected with TB bacteria that
are resistant to several drugs. If they have a positive
skin test reaction, they may be given preventive
therapy. This is very important for people who are at
high risk of developing MDR TB disease, such as
children and HIV-infected people.
- What is TB infection?
TB infection is detected by the administration of a
tuberculin skin test on the arm. A single needle is used
to put some testing material, called tuberculin, under the
skin. In two or three days, a nurse or a doctor will check
to see if there is a reaction to the test. The test is
"positive" if a bump about the size of a pencil eraser or
bigger appears on the arm. This bump means a person probably
has TB infection. A chest X-ray is done to see if someone
with a positive skin tests (TB infection) also has TB
People who are infected with TB do not feel sick, do
not have any symptoms and have a normal chest X-ray
cannot spread TB. However, they may develop TB disease
at some time in the future. People with TB infection
but are not yet sick can take medicine so that they
will never develop TB disease.
- How can a person get tested for TB?
A TB skin test is the only way to detect TB infection.
People can get a skin tested at the health department or at
their doctor's office. Not everybody is at the same risk for
TB infection and, therefore, do not to be tested. However,
persons should get tuberculin skin tested if they:
- have spent time with a person with infectious TB
- they have HIV infection or another condition that puts
them at high risk for TB disease
- think they might
have TB disease
- are from a country where TB disease
is very common (most countries in Latin America and the
Caribbean, Africa, and Asia, except for Japan)
- live somewhere in the U.S. where TB disease is
common (most homeless shelters, migrant farm camps,
prisons and jails, and some nursing homes).
If a person has a positive reaction to the skin test, a
doctor or nurse may do other tests to see if TB disease
is present. These tests usually include a chest x-ray
and a test of the phlegm people cough up. Because the
TB bacteria may be found somewhere besides the lungs, a
doctor or nurse may check the blood or urine, or do
other tests. Persons with TB disease need to take
medicine to cure the disease.
If a person has recently spent time with someone with
infectious TB, the skin test reaction may not be
positive yet. The person may need a second skin test 10
to 12 weeks after the last time they spent time with
the infectious person. This is because it can take
several weeks after infection for one's immune system
to be able to react to the TB skin test. If the
reaction to the second test is negative, the person
probably does not have TB infection.
Many people who have TB infection never develop TB
disease. In these people, the TB bacteria remain
inactive for a lifetime without causing disease. But in
other people, especially people who have weak immune
systems, the bacteria become active and cause TB
- What if a person has been vaccinated with BCG?
BCG is a vaccine for TB. This vaccine is not widely used in
the United States, but it is often given to infants and
small children in other countries where TB is common. BCG
vaccine does not always protect people from TB.
Persons who were vaccinated with BCG, may have a
positive reaction to a TB skin test. This reaction may
be due to the BCG vaccine itself or to a real TB
infection. But one's positive reaction probably means
that they have TB infection if:
- The skin test reaction is large
- the BCG vaccination
was administered many years ago (because the BCG
reaction gets smaller over time)
- the person has ever
spent time with a person with infectious TB
- someone in
the person's your family has had TB
- the person is
from a country where TB disease is very common (most
countries in Latin America and the Caribbean, Africa,
and Asia, except for Japan)
- What people with TB infection and are at risk of developing TB
Many people who have TB infection never develop TB disease.
But some people who have TB infection are more likely to
develop TB disease than others. These people are at high
risk for TB disease. They include:
- people with HIV infection
- people in close contact
with a person who has infectious TB
- people who became
infected with TB bacteria in the last 2 years
and young children
- people who inject drugs
- people who
are sick with other diseases that weaken the immune
- elderly people
- How is TB infection treated?
If a person has TB infection (a positive skin test reaction,
without the presence of TB disease ) and they are in one of
these high-risk groups, they need to take medicine to keep
from developing TB disease. This kind of treatment is called
preventive therapy. Also, if they are younger than 35 and
have TB infection without disease, they may benefit from
preventive therapy even if they are not in a high-risk
People who have TB infection but do not receive
preventive therapy need to know the symptoms of TB. If
they develop symptoms of TB disease later on, they
should see a doctor right away.
A single medication is usually used for preventive
therapy. It kills the TB bacteria that are inactive in
the body. If a person takes their medicine as
prescribed, preventive therapy will keep them from
ever developing TB disease.
Most people must take preventive therapy for at least 6
months. Children and people with HIV infection need to
take preventive therapy for a longer time.
Sometimes people are given preventive therapy even if
their skin test reaction is not positive. This is often
done with infants, children, and HIV-infected people
who have recently spent time with someone with
infectious TB disease. This is because they are at very
high risk of developing serious TB disease soon after
they become infected with TB bacteria.
It is important that people take all the pills
prescribed for them so that their preventive therapy
is effective. Persons starting on preventive therapy
need to see their doctor or nurse on a regular
schedule. He or she will check on how they are doing.
Very few people have serious side effects to INH.
However, patients should report side effects to their
doctor or nurse right away.
- What if a person has HIV infection?
A person can have TB infection for years without any signs
of disease. But if that person's immune system gets weak,
the infection can quickly turn into TB disease. Also, if a
person who has a weak immune system spends time with someone
with infectious TB, he or she may become infected with TB
bacteria and quickly develop TB disease.
Because HIV infection weakens the immune system, people
with TB infection and HIV infection are at very high
risk of developing TB disease. All HIV-infected people
should be given a TB skin test to find out if they have
TB infection. If they have TB infection, they need
preventive therapy as soon as possible to prevent them
from developing TB disease. If they have TB disease,
they must take medicine to cure the disease. TB disease
can be prevented or cured in people with HIV
- What is the history of TB?