TB Presentation for Healthcare Students

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TB Presentation for Healthcare Students

• ARPHS TB Control Programme July 2008

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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)

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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)

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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

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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

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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

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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)

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Symptoms of TB disease

• 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)

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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

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TB in Auckland (1995 2006)Proportion of cases
by ethnicity
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TB in Auckland (1995 2006)Age and ethnic
specific incidence rates
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TB in Auckland (1995 2006)Incidence by
ethnicity and birthplace
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TB in Auckland (1995 2006)Proportion of cases
by disease site
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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

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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

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Mantoux Test (continued)

• No test if there has been a previous Mantoux
  gt15mm 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

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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

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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