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Tuberculosis or
TB
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- Tuberculosis is an infection caused by an organism called Mycobacterium Tuberculosis. This is
an organism capable of causing infections throughout the
body, but the most common location is the lungs.
- M. Tuberculosis is a
bacterium found throughout the world. It is often very
difficult to treat. Often, when the organism invades the
body it triggers an immune response, killing off most of the
organisms in the course of the initial infection. This is
called a primary infection and often does not cause
significant symptoms.
- However, a few organisms will remain dormant, only to become active years later. This is called a reactivation. Various factors that weaken the immune system, such as multiple medical problems, chemotherapy, HIV Infection, or any
other immuno-affective conditions may trigger or contribute
to reactivation of the infection.
- Symptoms depend on which organ or part of the body is infected. Treatment also depends on the part of the body infected and the extent of the disease. Anti-Tuberculosis
medications are the main treatment. Treatment is a long
process and requires months to years of therapy, often with
multiple medications.
- Also, an increasing number of patients fail to respond to the usually effective medications. They have drug-resistant Tuberculosis. If
their infection fails to respond to antibiotics, it is
almost always fatal.
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- As stated, symptoms can vary
depending on which part of the body is infected.
- Tuberculosis can
infect almost any part of the body including, but not
limited to, the lungs, heart, brain, bone, spine, stomach,
kidneys, and fallopian tubes.
- The specific symptoms depend on the
area of the body infected.
- Some general symptoms include
weight loss, loss of appetite, low-grade fever, night
sweats, and fatigue.
- Pulmonary Tuberculosis occurs
when the organism infects the lungs. Symptoms include a
cough, which may be dry or productive of phlegm. Often,
there is coughing up of blood. An examination may not reveal
any significant abnormalities. Occasionally, the doctor may
detect the presence of fluid collection in the lungs.
- Tuberculosis Meningitis -- is a Tuberculosis infection of the brain or spinal cord. Symptoms may start with irritability and restlessness. Eventually, the patient develops stiff neck, headache, vomiting, Seizures, changes in
mental condition or behavior, or coma.
- Intestinal Tuberculosis --
is an infection of the intestinal tract. It was not very common in the United States until AIDS. Some of the symptoms include stomach pain, Diarrhea, Intestinal Obstruction, granuloma formation, intestinal
ulcerations with bleeding, or narrowing of the intestines.
- Tuberculosis
lymphadenitis -- involves M Tuberculosis
infecting the lymph nodes, causing enlargement of the nodes
and forming masses in the neck. This is known as scrofula,
and may sometimes drain to the skin.
- Tuberculosis Pericarditis --
occurs when the organism invades and infects the lining of the heart. This can cause fluid build-up around the heart, leading to more significant problems, including shortness of breath, fluid build-up in the lungs, Low Blood Pressure,
and even death.
- Tuberculosis
peritonitis -- involves an infection and fluid build-up in the abdomen. This is often very difficult to diagnose and is often missed. In addition to build-up of fluid in the abdomen, symptoms may include fever, weight loss, and weakness. Even with testing of the fluid, it is difficult to diagnose and may necessitate Laparoscopy to make
confirm diagnosis.
- Tuberculosis
salpingitis -- is an infection of the uterine fallopian
tubes that causes pelvic pain. Examination may reveal the
presence of masses in the pelvis, and the patient may report
irregular periods. It is not sexually transmitted.
- It is important to understand that many of these symptoms may also be present with numerous other medical conditions. Quite often, Tuberculosis is not
even suspected until other more common conditions are
treated without success.
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- As above, Tuberculosis is caused by Mycobacterium Tuberculosis, an
organism found throughout the world.
- Respiratory droplets most often
spread it person-to-person when people cough.
- Initially, the infection is acquired from another person. Once the organism enters the body, it spreads via the bloodstream and lymph system throughout the body. This is called primary Tuberculosis, and
often there are no symptoms. The immune system fights off
the infection, destroying the majority of organisms. Some
become dormant and survive within the body for years or even
decades. These organisms usually do not cause any problems.
- However, in a few cases,
reactivation of the disease occurs. This does not require
any new infection. The organism, dormant and inactive for
years, has become active again.
- The risk of reactivation increases
if the immune system is weakened for any reason.
- On average, a normal person who has been infected with Tuberculosis has
about a 10% chance of developing a reactivation of the
disease over the course of their lifetime. In people with
HIV, however, they have a risk of about 7% per year.
- In the past, it was thought that almost all adult cases of Tuberculosis were due to reactivation. However, newer testing methods have revealed that a sizeable number of adult cases may actually be due to newly acquired infections, especially in areas where there are a large number of people with Tuberculosis.
- People from certain parts of the world, such as the Philippines, China, Southeast Asia, Haiti, and India have a much higher risk of having resistant Tuberculosis. Resistant Tuberculosis occurs when the organism is not sensitive to the usual anti-Tuberculosis
medicines.
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- Diagnosis in almost all cases should be approached with suspicion. TB is notorious for progressing very slowly, and exhibiting only the vaguest of symptoms. It is often missed or misdiagnosed for a long period of time. Often, when patients are treated unsuccessfully for numerous other diseases, only then is the diagnosis of Tuberculosis actually considered. The doctor needs to be informed of any risk factors that may increase the chance of Tuberculosis in
order to consider it sooner.
- Even when the diagnosis is
considered early, confirming it can take a long time. In
some cases, tests are performed and the diagnosis made
within a few days. In other cases, the organism will have
to be cultured, which may take 4-8 weeks. At times, tests
may appear normal at first, and then come back abnormal,
i.e., positive for TB.
- In making the diagnosis, two main
tests are used.
- The first is called an AFB
stain or smear, in which a sample of suspect tissue is
stained with special dye, then examined under
microscope. This test is usually done within a day or
two.
- In the second test, a culture is used in an attempt to grow the organism in the lab. M Tuberculosis is
very slow growing and this test can take up to 6-8 weeks
for results. In some cases, the AFB stain may not show
anything, but the cultures may come back weeks later
with positive results. The culture results are extremely
important because they determine which drugs will work
against the organism.
- There are other tests used,
such as PCR, Bactec, and RFLP, but the two above are the
main diagnostic tools.
- Tests for diagnosing Tuberculosis depend
upon where the infection is located. The guiding principal
is that some of the suspect tissue or fluid has to be
removed and studied. If necessary, a biopsy is performed.
- For pulmonary Tuberculosis --
- The principal method of
diagnosis involves finding the organism in sputum
samples. Specimens are obtained immediately after waking
up (best results) on 3 consecutive days. The sputum is
then tested to see if the organism is present.
- When it is difficult to secure a sputum sample, a Bronchoscopy may
be required, using a camera to look into the lungs and
obtain specimens from the lungs and breathing tubes.
- The last option is to try to
culture the organism from early morning stomach fluid.
- Whenever Tuberculosis is suspected, Blood cultures
are used to discover if the organism is in the
bloodstream.
- A chest X-Ray is used to
discover infection of the lung.
- CT scans can also help identify
Lung Infection.
- In order to diagnose Tuberculosis in other parts of the body, tests are done of the suspect areas, including CT scan, Ultrasound, MRI scan, Echocardiogram,
endoscopy, etc.
- These tests are only suggestive. Final diagnosis can only be made by obtaining a specimen for establishing the presence of the Tuberculosis
organism, i.e., from sample of fluid or biopsy of the
suspected site of infection.
- In cases of suspected tuberculous Meningitis, a
spinal tap may be done.
- Another test, called a PPD, is usually administered to anyone suspected of having TB. See the section below labeled "Prevention" for more details. In most patients with Tuberculosis, it
will give a positive reaction. However, sometimes, the
test can be negative even in someone with the disease.
Similarly, a positive test does not absolutely confirm TB.
The test is helpful as part of the work-up, but it does
not make the
diagnosis.
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- Being around someone with active Tuberculosis
- Having a chronic illness such as
diabetes
- Having a weakened immune system,
either from HIV, chemotherapy, prolonged steroid use, etc.
- Working in the health care field
- Living in a long-term care
facility, such as a nursing home, mental institution, or
prison.
- Also, older people are at an increased risk of developing Tuberculosis.
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- Treatment for Tuberculosis should
be started on all individuals in whom the doctor suspects
the disease. If there is any risk that the patient may not
take the medications, or may expose others, then initial
treatment needs to be done in the hospital. Most of the
time, other household members have already been exposed, and
isolation from them is not needed. However, if there is a
possibility of new exposures, then isolation is in order. In
the hospital, patients are placed in a special room (called
a negative pressure room), to prevent spread of the disease
to staff and others. All hospital staff and family members
in contact with the patient will have to wear protective
masks.
- Treatment -- there are many options
and treatment needs to be tailored to the individual and his
lifestyle, as well as to the location and type of the
infection
- There are two main conditions of
treatment. In the first case, the patient is treated at
home, coming in for periodic check-ups. In the second,
called DOT (directly observed therapy), the patient comes
into the health department or other agency 2-3 times a
week for medication, to ensure that he is actually taking
his medicines.
- The four main drugs used to treat Tuberculosis are Isoniazid, Rifampin, Pyrazinamide, and either Ethambutol or Streptomycin. Usually four (4) of these drugs are given in combination to treat almost all Tuberculosis
infections.
- Treatment is with four medications until the tests identify which anti-Tuberculosis medicines will be most effective. Medications are adjusted accordingly. Usually, all four are continued for about 4-6 weeks. If the organism proves to be sensitive to Isoniazid and Rifampin, they are continued, and Ethambutol or Streptomycin is stopped. Pyrazinamide is
continued for 8 weeks then stopped. Therapy is continued
for at least 6 months, or for at least 3 months after the
cultures are negative -- whichever is longer.
- There are various combinations of
treatment and the best option will have to be tailored to
the patient's needs by the doctor and the health care
department.
- In patients with HIV, they need
to continue treatment for a minimum of 9 months, or for 6
months after the cultures are negative.
- If cultures are not available to
guide the doctor, options will need to be discussed with a
specialist because the type, length, and method of
treatment all vary.
- Directly observed therapy (DOT) is more expensive to administer, but it ensures that the patient takes his medicines, especially in those with drug-resistant Tuberculosis, and
in those who refuse to take their medication or have
difficulty following directions.
- Treatment for Tuberculosis outside the lungs is usually the same as pulmonary Tuberculosis, but
it is usually continued for at least 9 months.
- Steroids can be used for people with Tuberculosis Meningitis and Tuberculosis Pericarditis to
help reduce inflammation.
- Streptomycin should not be used by pregnant women. Pyrazinamide use
during pregnancy is not advised either.
- All treatment starts with
multiple medications because of the risk of resistance if
only 1 or 2 medications are used. Treatment should start
with all four, and then altered according to results.
- Patients should take all of their
medicines until the doctor tells then to stop. If the
doctor's orders are not followed, there is a high risk of
not adequately treating the infection. The organism may
become resistant, making repeat infection difficult to
treat.
- Tuberculosis
lymphadenitis is treated with surgery to remove all infected
lymph nodes, after which the patient is placed on anti-TB
medications.
- Tuberculosis Meningitis --
using the four anti-TB medications described above,
treatment has to be started even before all of the test
results are back. Occasionally, steroids may also be used in
the case of nerve deficits.
- Tuberculosis Pericarditis --
requires drainage of the fluid and anti-TB medications. In
some cases, the sac surrounding the heart may have to be
removed.
- Tuberculosis
peritonitis -- is treated with the usual combination of
anti-TB medications.
- Tuberculosis
salpingitis -- this is treated with the usual anti-TB
medications. If there is a large mass, or if the TB does not
respond to medication, surgery may be necessary.
- The risk of contracting
drug-resistant TB increases in regions known to have a high
incidence of drug-resistant TB. Other high risk factors for
drug resistant TB include close contact with someone with
drug-resistant TB, previous unsuccessful treatment for TB,
and previous failure to take all medicines and complete
treatment. The risk of drug-resistant TB is especially high
in the United State in large urban centers, such as New
York, Dallas, and Los Angeles. In those with drug-resistant
TB, the infection is almost always fatal, unless an
alternative drug regimen is found and followed. This
requires the input of trained specialists to help structure
treatment options.
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- There are many potential complications of varying severity that may occur with Tuberculosis,
depending on the location and kind of infection.
- In Lung Infections, there can be
fluid build-up around the lungs, resulting in shortness of
breath and/or fluid collection within the lung. In such
cases, removal of part of the lung may be necessary.
- In cases of intestinal tuberculosis
infections, patients may develop obstruction, perforation,
malabsorption, or bleeding from the intestine.
- In those with brain infections, patients may develop chronic brain syndrome, Seizures, neurological deficits, Stroke, or hydrocephalus.
- People with heart infections can develop constrictive Pericarditis.
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- Seek medical attention as soon as
possible.
- It is important to inform the doctor or health care workers immediately if you think that you have Tuberculosis.
Precautions can be taken to prevent spread of the infection.
- Until the diagnosis is made, it is
best to try to avoid contact with others to prevent
spreading.
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- Prevention is the key to
controlling this disease.
- The first line of prevention is to
try to keep the infection from spreading by isolating anyone
with an active virus until the infection is brought under
control. In modern hospitals, negative pressure rooms
prevent the infection from spreading within the hospital.
- Also, facemasks may be used to trap
the organism and prevent its spread. All those in contact
with the patient should wear them. They may also be worn by
the patient, allowing him mobility so long as the mask is
secure.
- Anyone even suspected of having the
infection should be isolated immediately, or given a mask to
wear to prevent the infection from spreading. Discontinue
such precautions only when it safe to do so -- when it has
been proven that the patient no longer has the infection, or
was falsely diagnosed and never had it.
- People with active Tuberculosis are very
infectious, and may easily spread the disease to others
around them by coughing or sneezing. As stated above, they
must be kept in isolation until they no longer pose a risk
-- when at least 3 separate AFB tests prove normal and they
evidence no other indications of the presence of the
organism.
- The PPD skin test -- is a screening
test commonly done in the United States, and is often used
as part of a strategy to prevent the disease.
- The PPD skin test is done by injecting a small amount of protein (derived from Tuberculosis
bacteria) under the skin of the forearm -- swelling and
redness indicate a positive result.
- The test result is determined 48
hours after injection.
- It reveals only previous exposure to Tuberculosis. It
does not determine whether the test subject has an active
infection, or merely past exposure to the organism. The
PPD test result has to be interpreted based on a number of
factors. Alone it is not conclusive.
- In a patient with HIV who has had close contact with someone infected with active TB, and in patients with X-Ray evidence of prior healed Tuberculosis, a PPD
test is considered to be positive if the swelling is more
than 5 millimeters in width.
- Subjects from countries with a
high rate of TB, HIV-positive IV-drug users, those in
correctional facilities or nursing homes, people from
medically- underserved areas, and people with certain
medical conditions are considered to have a positive PPD
if the swelling is more than 10 millimeters in diameter.
- The rest of those tested are
considered to have a positive PPD if the swelling is more
than 15 millimeters in diameter.
- In some cases, test subjects may
initially have a negative skin test but on repeat testing,
their skin test may turn positive. This may be a "booster
phenomenon," in which the first test triggered an immune
response, rather than a true conversion to a positive
test.
- The PPD test is not 100% accurate. Some who do not have the infection will have a positive test result. These false positives occur occasionally in those with an infection closely related to Tuberculosis.
- Also, there are those who have a negative test but do have the infection. These false negatives occur more often in the malnourished, older people, those with AIDS, those on steroids, those with severe Tuberculosis, those
with certain types of cancers, people with kidney failure,
people who are very ill from other causes, or those in
whom the test was not administered properly.
- People who have been given the
BCG vaccine may have a positive skin test for a year after
the vaccination. After a year, their skin test response
should be interpreted the same as anyone else.
- Also, some people do not react to
the PPD skin test at all. They are said to be anergic, and
they do not have any response to skin tests. Their test
results are of no value. To determine anergic test
subjects, give other injections to see if they have any
response.
- Most patients given preventive therapy for Tuberculosis usually receive six (6) months of Isoniazid.
- All subjects with a positive PPD
should be given preventive therapy if they fall into one of
the following categories:
- All people with HIV. Also, if the person is HIV positive and has a high risk of Tuberculosis, then
they need to be given preventive therapy even if their
skin test is negative.
- All people who are close contacts of someone with Tuberculosis and
have a positive skin test. Children must be treated with
preventive therapy even if their skin test is initially
negative. Children should be re-tested 3 months later, and
if they test positive, they will need to continue therapy
for a total of nine (9) months.
- Anyone who has recently developed
a positive skin test (within the past 2 years). That is,
they previously had a negative skin test and then became
positive.
- People with medical conditions that increase their chances of developing Tuberculosis should
be treated with preventive medications. This includes
patients with diabetes, people on chronic steroid therapy,
those with blood cancers, intravenous drug users, people
with kidney failure, and people who are undernourished.
- In the following cases, only those
who are under 35 years old and have a positive PPD need
preventive therapy:
- People born in countries with a high rate of Tuberculosis, such
as African, Asian, and South American countries.
- People from the U.S. who are
medically underserved or have very low incomes.
- People who live in or work in
long-term care facilities, such as mental institutions and
nursing homes.
- All other people who do not have risk factors for Tuberculosis but have
a positive skin test with more than 15 millimeters of
swelling should be given preventive therapy if they are
under 35 years of age.
- In most cases, preventive therapy is with Isoniazid for 6
months. In children, therapy is continued for 9 months.
- People who are on Isoniazid are usually given Vitamin B6 to help reduce side effects of Isoniazid.
- Also, people on Isoniazid need to
have liver tests done prior to starting therapy. They will
need to be monitored with questioning to see if they develop
symptoms of hepatitis. If they do, blood tests will be
needed, and the medicine stopped if they have elevated liver
tests. If they are under 35 and have no symptoms, routine
testing is not needed. If over 35, routine blood tests to
check the liver may be warranted.
- BCG vaccine (BCG stands for bacille
Calmette-Gu?in) --
- In some countries, this vaccine
is routinely used.
- In the United States, it is not common. It is used mainly in people who have a positive PPD but cannot take Isoniazid
prophylaxis.
- Also, it can be given to PPD negative children who are exposed to people with inadequately treated Tuberculosis but
cannot receive the usual preventive treatments.
- This vaccine can also be used in
areas where there is a high rate of new infections,
despite appropriate measures to prevent new infections.
- BCG has been shown to reduce the risk of developing Tuberculosis.
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