Transcript Orientation

TB Presentation for
Healthcare Students
ARPHS TB Control Programme
July 2008
Overview
• What is TB/latent TB infection
(LTBI)/active TB disease?
• How does TB spread, who progresses
from LTBI to TB disease, symptoms of TB
disease
• TB in Auckland
• Why must you be screened?
• Tests (Mantoux skin test, IGRA blood test,
chest x-ray, other tests)
What is TB?
• Tuberculosis (TB) is a bacterial infection
• Caused by Mycobacterium tuberculosis (or
rarely, Mycobacterium bovis)
• TB can affect any part of the body
• TB can be in the lungs (pulmonary TB),
and/or in other parts of the body e.g.
lymph nodes, brain, kidneys, bowel, etc
(extrapulmonary TB)
What is latent TB infection
(LTBI)?
• LTBI is the initial infection with TB bacteria
• A person with LTBI has TB bacteria in their
body which are dormant – inactive or
‘asleep’
• If you have LTBI you are not infectious to
others
• If you have LTBI you are well and have no
symptoms of TB disease
What is TB disease?
• Only about 10% of people with LTBI go on
to develop active TB disease at some
stage during their lives – 90% do not
• TB disease can develop from within
several months or years of becoming
infected, up to 40+ years later
• The TB bacteria become active (‘wake up’)
• If you have TB disease you are sick
• TB disease in lungs or throat may infect
others
How does TB spread?
• Not all TB is infectious – only TB in the
lungs (pulmonary TB) or throat (laryngeal
TB) can infect other people
• TB spreads through the air
• People catch it by inhaling droplets
(aerosols) containing TB bacteria
• Droplets are produced by someone with
TB in their lungs or throat – by coughing,
sneezing, talking, singing
• TB is not easy to catch – usually takes
many hours of exposure to be infected
Who is more likely to progress
from LTBI to TB disease?
• Recent infection – a higher risk of
developing TB disease within 2 years of
becoming infected with the bacteria
• People whose immune systems are weak
– including people with HIV/AIDS, cancer,
kidney disease, diabetes, taking cancer
chemotherapy drugs, or on long term oral
steroid treatment (not asthma inhalers)
Symptoms of TB disease
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Unexplained weight loss
Unexplained fever
Loss of appetite
Sweating (especially at night)
Feeling tired or weak all the time
Cough lasting 3 weeks or more, and not getting
better
Coughing up blood or bloody sputum (spit)
Chest pain
Shortness of breath
Symptoms related to part of body affected e.g.
enlarged lymph nodes (glands)
TB disease in Auckland
• 155 notified cases of TB disease in 2006
(average 186 cases annually between
1995-2006)
• TB rates increase as people get older –
but there is also a peak in young adults
• Every year there are several TB cases in
healthcare workers, including students
• Some of the healthcare workers/students
with TB are infectious to others
TB in Auckland (1995 – 2006)
Proportion of cases by ethnicity
TB in Auckland (1995 – 2006)
Age and ethnic specific incidence rates
TB in Auckland (1995 – 2006)
Incidence by ethnicity and birthplace
TB in Auckland (1995 – 2006)
Proportion of cases by disease site
Why must you be screened?
• To protect you, the students – to establish
your baseline TB infection status, before
exposure to potentially infectious patients
• To identify any students with latent TB
infection (LTBI) – to give advice to all with
LTBI, & offer treatment to highest risk
• To protect patients – from any students
with undiagnosed infectious TB
Tests – Mantoux test
• A skin sensitivity test to detect past
exposure to, and infection with, M.
tuberculosis and related bacteria
• Mantoux test solution is made from part of
the TB bacillus
• It is a safe test - 0.1ml of test solution is
injected under the skin, and is read and
measured 3 days later to decide if the test
is positive or negative
• A negative test is repeated 1 week later
Mantoux Test (continued)
• No test if there has been a previous
Mantoux >15mm or a past history of TB (to
prevent large skin reactions)
• It is safe for pregnant women
• Strongly positive results may be painful
and itchy for a few days
• Students with a positive test will be
required to have a chest x-ray
Tests – IGRA blood test
• This is a newer type of blood test for LTBI
• It can be done if your Mantoux test is
positive, or instead of a Mantoux test
• The test results are less affected by BCG
vaccination, and the test is more specific
for infection with Mycobacterium
tuberculosis, when compared with the
Mantoux test
Tests – chest x-ray & other
• If you have LTBI (positive Mantoux and/or
IGRA), you must have a chest x-ray to
check that you do not have active TB
disease in your lungs
Important: You will not be able to go
on clinical placement unless you
complete the TB screening procedure