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Tuberculosis
BP takes a look at
TB and offers a general guide to understanding this re-emerging disease...
Over the last couple
of decades, there has been a disturbing increase in the number of people
worldwide becoming infected with Tuberculosis and it has re-emerged with
a vengeance in the UK. Provisional data now shows that for the year 2000,
reported cases have risen by over 10% since 1999, with the greatest proportion
occurring in London particularly amongst immigrant/transient populations
and the homeless. These are the highest levels since 1983 - an increase
of 71% since 1988. In London, at least 50 people a week develop TB and
mortality rates are high. It is clear from these figures that TB is again
a concern in Britain, however, TB is curable and preventable.
What
is TB?
Tuberculosis is an infectious, communicable disease caused by the bacterium
Mycobacterium Tuberculosis but there is an important distinction between
TB infection and TB disease. TB mycrobacteria can live in your body without
making you ill. This is known as TB infection or latent infection and
is non-infectious. Sometimes you can become ill after the first exposure
to TB (thus called primary TB) but normally, if you are reasonably healthy,
your immune system will simply trap the bacteria and stop them from making
you ill. However, even years later, the organisms can break away from
this trap and spread to other parts of your body and when this happens,
the actual disease can develop (this is called reactivation TB).
In around 90% of
people with primary TB infection, the body's immune system will suppress
the infection without killing the bacteria which remain alive but dormant,
sometimes causing this reactivated form of TB. Another form, re-infection
TB, occurs when someone with the dormant, primary form is re-infected.
This type of TB is clinically identical to the reactivated form..
It is possible to transmit some strains of TB by air ( by an infected
person coughing or sneezing the germs
(bacilli) into the air which are then breathed in by another,
or by swallowing contaminated food. However, it is generally close contact
over an extended period with an infectious person that is needed in order
to become infected by another person so it is unlikely you will catch
TB from someone coughing on the bus.
"Tuberculosis is usually known as being linked to the lungs but in
reality can occur in almost any part of the body".(quote box)
While TB is usually
thought of as only being linked to the lungs, in reality it can affect
almost any part of the body's organs or tissues. The lining of the heart
can become infected (pericardium), as can the lining of the abdominal
cavity, the brain, bones and joints, the larynx, bronchus and lymph nodes.
The male and female reproductive organs can also be affected. It is when
TB affects a part of the body other than the lungs or throat that it is
known as extra-pulmonary TB and the person will not be infectious. However,
even years later, the bacterium can travel to the lungs from somewhere
else in the body which then causes the person to become infectious to
others.
New and varied strains
of TB have also emerged over the years and most recently, a strain known
as MDR TB (multi-drug-resistant TB). This very virulent strain has developed
immunity to the two most powerful and often used anti-TB drugs. These
strains have developed through the incorrect usage of antibiotics by both
doctors andpatients alike. Because the drug treatment used for TB is needed
for many months (6 months to a year), sometimes people stop taking their
medication because they begin to feel better. This is a mistake. Seeing
your course of TB tablets through to the very end is crucial - when it
says complete the course on your antibiotics it's not a suggestion but
part of the remedy.
SYMPTOMS
A person with TB infection will have no symptoms. A person with TB disease
may have any, some or none of the following symptoms. If you develop these
symptoms it is important that you see a doctor, particularly if you have
had TB before or are known to be latently infected. If you are already
on medication and these symptoms develop you should tell your TB specialist.
The medication you are taking may not be working properly, and they may
need to change the drugs.
- Tightness or pain
in the chest, a cough with phlegm (which may be bloodstained) -
- Shortness of breath when doing tasks that are not particularly strenuous.
- Loss of appetite (some people experience spectacular weight loss)
- A fever that gradually rises throughout the day and/or nightsweats
- Lumps in the neck may appear or swelling of the joints
- Weakness or a general feeling of unease.
"Seeing a course
of TB tablets through to the end is crucial - when it says complete the
course on your antibiotics, it's not a suggestion but a critical part
of curing TB" (quote box).
TREATMENT
So, what is possible when it comes to treating a disease such as TB? The
aim of treatment is to cure the disease. The tests for discovering whether
a person has TB usually involve physical examinations, chest x-rays, sputum
tests and sometimes examining the lung via a fibre-optic bronchoscope.
In other parts of the body, TB can be found by testing samples of, for
example, lymph node or liver tissue. Anti-tubercular drugs are widely
available in the UK and one will have to use several medications together
for the duration of treatment, which tends to be around 6 months or longer.
It may be hard to stick to such a long-term regime if your living situation
is difficult or chaotic (TB drugs can sometimes have difficult side-effects),
but it is essential to complete the treatment if you want to get better.
If you miss a few doses, you must inform your doctor immediately. Sometimes
short periods of quarantine will be required to protect other people from
contracting the infection. After 2 weeks of drug treatment, the patient
is usually sent home as they are no longer infectious. This can pose a
problem for drug users but it is vital you arrange a 'script to last the
duration of your hospital stay if it's needed. Invariably, health care
workers will be more worried about the TB than giving you a prescription
for a few weeks.
The treatment for MDR TB is more complex. Whilst this is also treatable
it can require extensive chemotherapy for up to 2 years which is extremely
toxic for the patient as well as undergoing periods in isolation in hospital.
MDR-TB can usually be treated successfully after identifying the drugs
to which the organisms are still susceptible. For people with HIV and
on combination therapy, protease inhibitors can interact with some TB
treatment drugs, so alternative TB drugs may have to be used, or the protease
inhibitor may have to be stopped until the TB treatment is completed.
As mentioned earlier, TB, especially when left untreated, can spread to
other parts of the body causing a lot of damage and even death.
PREVENTION
Pulmonary
TB may exhibit no symptoms in its early stages which is why regular chest
x-rays are important in areas where TB is prevalent. Anyone living with
a patient should be examined for infection as soon as possible. Usually
healthy adults who have had a BCG vaccination (most British people will
have had this injection in their youth) will not become infected with
TB. If you have not had an injection, make sure you see your doctor to
discuss whether to have the vaccination. Overcrowding and damp, unsanitary
living conditions can encourage the transmission of TB so avoid these
situations as much as possible or ensure there is always a good source
of natural ventilation in the room. If you think a friend may have TB
(they may have a bad cough that lasts longer than 2 weeks and a low grade
fever), encourage them to get checked out by a doctor. There are TB Clinics
attached to many hospitals, which can treat you immediately. Stephen Brennen
PIC scroll down to
pic below
Sites of TB infection (under pic)
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