Outline











Transmission
Mycobacteria
Pathogenesis
LTBI
LTBI vs TB Disease
Symptoms of TB Disease
Factors which increase the Risk of Developing TB Disease
Sites of TB Disease
Treatment of TB Disease
Medications
Drug Resistant TB
A.
Brief History of TB
 Afflicted mankind since ancient times.
 Evidence of TB found in Egyptian and Peruvian
mummies.
 In the 19th century, the disease was often referred to
as “consumption”. Other names – “wasting disease”,
“White Plague”.
2
Tuberculosis remains a Global Concern
 Among infectious diseases, TB remains the second leading killer
of adults in the world, with more than two (2) million TB related
deaths per year. It is estimated that 1 in 3 people on earth are
infected with the TB bacillus.
 Developing countries have the highest rates of TB. The incidence
rate of tuberculosis in Canada is considered low (5.1 per 100,000),
especially in the global context.
 The highest incidence rates of TB in Canada are reported among
Canadian-born Aboriginal peoples. There are wide fluctuations
even among this group. In Ontario, rates are much lower among
First Nations reserves than in Manitoba, Saskatchewan and the
far north.
3
History of TB in First Nations
 The history of TB in First Nations is a very painful and sad one. For many
people a diagnosis of TB was a death sentence. Deaths resulting from TB in
the early 20th century were at an estimated 42.6 per 1000 in the Indian
population in western Canada.
 Some First Nations people with TB were sent to sanatoria far from their
communities. Many did not return for years and some felt like strangers in
their community and family. Some patients died in the sanatorium and
families never saw them again.
 It is understandable that First Nations people who remember this have
very negative feelings about TB.
Fort William Sanatorium
4
Elders and TB Stories
…Elders tell their stories…
TB is spread from person to person through the air.
The dots in the air represent droplet nuclei containing
tubercle bacilli.
What is Tuberculosis?
TB is a disease caused by an organism called
Mycobacterium tuberculosis, a member of the
bacteria family.
8
Pathogenesis ( the mechanism that
causes the disease) of Tuberculosis
How does TB enter the body?
Droplet nuclei containing tubercle bacilli are
inhaled, enter the lungs, and travel to the alveoli.
10
Infection begins when droplet nuclei reach the
alveoli.
11
A small number of tubercle bacilli enter the bloodstream
and spread throughout the body. The tubercle bacilli
may reach any part of the body, including areas where
TB disease is more likely to develop (such as the lungs,
kidney, brain, or bone).
12
Within 2 to 8 weeks the immune system produces
immune cells called macrophanges that surround the
tubercle bacilli. The cells form a barrier shell that
keeps the bacilli contained and under control. This is
known as Latent TB Infection (LTBI).
13
Latent TB Infection ( LTBI)
 Latent TB infection (LTBI) means that tubercle bacilli
are in the body, but the body’s immune system is
keeping the bacilli under control and inactive. The
immune system does this by producing special
immune cells that surround the tubercle bacilli. The
cells form a shell that acts as a fence and keep the
bacilli contained and inactive.
If the immune system cannot keep the tubercle bacilli
under control, the bacilli begin to multiply.
This is TB disease. This process can occur in different
places in the body such as the lungs, kidneys, brain,
or bone.
15
LTBI
TB Disease
 Latent TB Infection ( LTBI)
 Tuberculin skin test results
 TB disease in the lungs
 Active tubercle bacilli in the






usually positive
Chest xray usually normal
Sputum smears and cultures
negative
No symptoms
Not infectious
Not a case of TB





body
Tuberculin skin text results
usually positive
Chest x-ray usually abnormal
Sputum smears and cultures
may be positive
Symptoms such as cough,
fever, weight loss
Often infectious before
treatment
A case of TB
Symptoms of TB disease
 Cough for more than 3 weeks.
 Extreme tiredness
 Fever
 No appetite
 Weight loss
 Sweating at night
TB is not easy to catch!
 You generally have to spend a lot of time with a person
coughing or sneezing germs at home, work, or school
in order for you to catch TB germs.
 The disease spreads most easily in closed dwellings
with little sunlight and poor air circulation.
These four factors influence the probability
that TB will be transmitted.
Conditions that increase the risk of
developing TB disease.












Infection with HIV
Chest x-ray findings suggestive of previous TB
Substance abuse ( especially illegal injection drug use)
Recent TB infection ( within the past 2 years)
Prolonged therapy with corticosteroids and other
immunosuppressive therapy such as prednisone
Organ transplant
Silicosis
Diabetes Mellitus
Severe kidney disease
Certain types of cancer
Certain intestinal conditions
Low body weight ( 10% or more below ideal)
Risk of Developing TB Disease
Sites of TB Disease
 Pulmonary TB – TB that occurs in the lungs. Most cases of
TB are pulmonary. Patients usually have a cough and an
abnormal chest x-ray
 Extrapulmonary TB- occurs in places other than the lungs
such as the larynx, the lymph nodes, the pleura ( the
membrance surrounding each lung), the brain, the
kidneys, or the bones and joints.
 Miliary TB- occurs when tubercle bacilli enter the
bloodstream and are carried to all parts of the body where
they grow and cause disease in multiple sites. Chest xray
has the appearance of millet seeds scattered throughout
the lung
Remember:
 Only pulmonary/laryngeal TB is contagious and can
be spread to others.
QUIZ
 1) A person with TB infection can spread TB germs to others.
T F
 2) People with TB disease lose weight.
T F
 3) TB Infection is when the TB germs are sleeping in your body and not making
you sick.
T F
 4) Once a person catches TB germs, they will have them all their lives.
T F
 5)You will feel weak and tired all the time if you have TB Disease.
T F
 6) TB is only found in the lungs.
T F
 7)TB can be cured.
T F
 8)TB disease is when the TB germs start growing and making the person sick.
T F
 9) TB germs can be spread through the air from one person to another. T F
The good news now is… there is a cure for TB!!
25
Treatment of TB Disease
 TB disease must be treated for at least 6 months
 Most of the tubercle bacilli are killed during the first 8
weeks of treatment ( the initial phase)
 Treatment with at least two drugs must be continued
for several more months to kill the remaining bacilli
(the continuation phase)
Medications
 The initial regimen for treating active TB disease





should include the following four drugs:
Isoniazid
Rifampin
Pyrazinamide
Ethambutol
TB disease must be treated with at least two drugs to
which the bacilli are susceptible
Drug- resistant TB
Drug-resistant TB
Can be caused in two different ways:
Primary – caused by person-to-person transmission of
drug-resistant organisms
Secondary – develops during TB treatment, either
because the patient was not treated with the
appropriate treatment regimen or because the patient
did not follow the treatment regimen as prescribed
How does drug resistant TB
develop?
 Patient does not take their medicine regularly.
 Patient does not take all of their medicine, as told by
their health care provider
 Patient develops active TB disease again, after having
taken TB medicine in the past
 Patient comes from area of the world where drugresistant TB is common
DOT- Directly Observed Therapy
 Directly observed therapy means that a health care
provider administers the medication to the client
 Assists the client to consistently take their medication
until completion.
E.
Treatment of TB Disease
 Untreated TB carries a high mortality rate
 More than one drug is required for cure
 Usual regimen for uncomplicated TB:
4 drugs x 2 months
2 drugs x 4 months
 In consultation with a TB specialist, drug therapy may continue
for 9, 12, or more months.
 Poor compliance leads to relapse and drug resistance. Directly
Observed Therapy (DOT) is the ‘gold standard’ world-wide.
 Even with perfect compliance a small % will relapse.
32
Review Questions
 What organism causes TB?
 How is TB spread?
 The probability that TB will be transmitted depends
on what four factors?
 What is drug-resistant TB?
 What is the difference between primary and secondary
drug-resistant TB?
REMEMBER:
 If you need more information about TB, contact the
Tuberculosis (TB) Control Program
 (807) 737-4797
 Toll Free: 1-855-885-8824