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Tuberculosis
WHAT IS
TB?
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
TB.
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 TB.
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. 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.
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.
WHO GETS IT?
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
WHAT ARE THE SYMPTOMS OF
TB?
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.
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 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.
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.
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).
Q:
Should you get a skin test each year to check on
TB?
A: Only if you are at high risk for getting
or transmitting TB or your jobs request it.
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 active TB disease. (Some people
get skin tests because of their jobs, in a school or
hospital, for example, to make sure they have not
contracted TB and will not infect others if they have
TB).
If you fall into one or more of the
high-risk categories for TB noted earlier- for example,
if you are HIV-positive, never had a skin test before,
or there is no record of the last result- you should be
tested.
Some doctors and clinics may now use
newly developed blood tests instead of the PPD skin
test. 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 active TB disease or only TB
infection.
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.
What
if the person has active 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. 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.
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.
WHAT
IS ENTENSIVELY-DRUG RESISTANT TB?
Extensively-drug resistant tuberculosis
(XDR TB) is a strain of TB with extensive resistance to
second-line drugs. XDR TB has emerged worldwide as a
threat to public health and TB control, raising concerns
of a future epidemic of virtually untreatable TB.
Presently, XDR TB is rare in the U.S. and uncommon in
the rest of the world. During 1993-2002, patients with
XDR TB were 64% more likely to die or have treatment
failure.
CAN A TB PATIENT INFECT
OTHERS?
Yes, if they have TB disease and it is
not being treated. 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.
TB: WHAT YOU SHOULD
DO
Find
out if you're infected.

Certain people such as those infected
with HIV or health care workers should be tested
regularly. You should be tested if there's any chance
you have been infected, recently or many years
ago.
If
the test is negative:
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.
If
the test is positive:
A
significant reaction usually means that you have been
infected with the TB germ. It does not necessarily mean
that you have TB disease. Cooperate with the doctor when
he or she recommends a chest X ray and possibly other
tests.
If
the doctor recommends treatment to prevent sickness,
follow the recommendations. If medicine is prescribed,
be sure to take it as directed.
If
you don't need treatment, do what the doctor tells you
to do about follow-up. The doctor may simply say
to return for another checkup if you get into a special
risk situation for TB sickness or develop
symptoms.
If
you are sick with TB disease, follow the doctor's
recommendations for treatment.
If
you're a health worker:
Your
local American Lung Association can provide you with
more comprehensive information developed for health
professionals on the diagnosis, treatment and control of
TB. |