Tb

Introduction
1

Tuberculosis Partners in Global Health Education

w to use this module
Welcome to the tuberculosis (TB)
arning outcomes
at is TB? module.
demiology
robiology
nsmission TB is a major cause of morbidity
ction 1 quiz
ural history
and mortality all over the world but
ction 2 quiz the greatest burden is borne by
mptoms and signs
ction 3 quiz
developing countries. The
gnosis bacterium Mycobacterium
atment
vention and control tuberculosis is responsible for most
ction 4 quiz
ormation sources
TB cases.
mmative assessment

For more information about the authors and
reviewers of this module, click here
IUATLD; WHO/TBP/Falise

Introduc
tion 2

How should you study this module?
Partners in Global Health Education

• We suggest that you start with the learning objectives and try to
keep these in mind as you go through the module slide by slide,
w to use this module in order.
arning outcomes
at is TB?
• Print-out the mark sheet
demiology • As you go along, write your answers to the questions on the
robiology mark sheet as best you can before looking at the answers.
nsmission
• Award yourself marks as detailed on the mark sheet: one mark
ction 1 quiz
for each keyword (shown in red text) in the short answer
ural history
questions and for every correct answer in the True/False
ction 2 quiz
questions.
mptoms and signs
ction 3 quiz
• Repeat the module until you have achieved a mark of 28/35
gnosis
(≥80%).
atment • Finish with the formative multiple choice questionnaire to assess
vention and control how well you have covered the material as a whole.
ction 4 quiz
ormation sources
• You should research any issues that you are unsure about. Look
mmative assessment
in your textbooks, access the on-line resources indicated at the
end of the module and discuss with your peers and teachers.
• Finally, enjoy your learning! We hope that this module will be
enjoyable to study and complement your learning about TB from
other sources.

Introduc
tion 2

Learning Outcomes

w to use this module By the end of the module, you should be able to:
arning outcomes
at is TB? 1. Describe how TB can affect anyone, of any age, anywhere, but that
demiology most cases occur in specific risk groups
robiology
nsmission
2. Describe how respiratory droplets are the main transmission agent
ction 1 quiz
ural history
ction 2 quiz
3. Describe how, following inhalation, M. tuberculosis causes infection in
many people and disease in some
mptoms and signs
ction 3 quiz
gnosis
4. Enumerate the general symptoms and signs of TB and the specific
clinical features of pulmonary TB
atment
vention and control
ction 4 quiz 5. Discuss how CXR and sputum examination are used in diagnosis
ormation sources
mmative assessment 6. Describe how TB is managed using combinations of antimicrobials

7. Describe how TB is prevented at the community level by immunisation,
case finding and contact tracing

What is tuberculosis (TB)?

TB is a chronic bacterial infection. The great majority of infections in
arning outcomes
people are caused by Mycobacterium tuberculosis (M.
at is TB? tuberculosis). A closely related bacteria, M. bovis, causes TB in
demiology animals (especially cattle) and can infect people who drink
robiology unpasteurised milk from infected cows.
nsmission
ction 1 quiz Although an ancient disease, TB
ural history remains a world wide problem:
ction 2 quiz
mptoms and signs
• about 1 in 3 of the world’s
ction 3 quiz population is infected with tubercle
gnosis
bacilli and someone is newly
atment
vention and control infected every second
ction 4 quiz • although most infected people
ormation sources
mmative assessment
remain asymptomatic, there are
about 9 million new cases and
nearly 2 million TB deaths every
year.

Where does TB occur? Epidemiology 4


About 95% of the world’s cases of TB occur in South East Asia, sub-
Saharan Africa and the Western Pacific.
arning outcomes The largest number of cases and
at is TB? highest mortality occur in South East
demiology Asia and this region accounts for 33%
robiology of incident cases globally.
nsmission
The annual incidence of TB is
ction 1 quiz
increasing sub-Saharan Africa mainly
ural history
as a result of the increased
ction 2 quiz
susceptibility of people infected with
mptoms and signs
HIV.
ction 3 quiz
gnosis Other factors which encourage TB
atment
transmission are:
vention and control • the emergence of multidrug-resistant strains of M. tuberculosis
ction 4 quiz • poor national TB control programmes and worsening socio-economic
ormation sources conditions in many countries
mmative assessment
In the UK, the annual incidence rate is increasing with >8,000 new
cases/year. Most occur in the larger cities, especially London, and
about 2/3 cases occur in people who were born abroad. TB causes
or contributes to 300-400 deaths/year in the UK.

pidemiology 2

Microbiology (1) Partners in Global Health Education

M. tuberculosis is a non-motile, rod-shaped
bacterium measuring 2-4 x 0.2-0.5 μm. It is
arning outcomes
an obligate aerobe, which explains why it
tends to be found in the well-aerated, upper
at is TB?
lobes of the lungs.
demiology
robiology
nsmission
It is a slow growing organism (dividing only
ction 1 quiz
every 16-20 hours) that lives within tissue
macrophages. Humans are the only
ural history
reservoir of M. tuberculosis. Both animals
ction 2 quiz and humans serve as reservoirs for M.
mptoms and signs bovis.
ction 3 quiz The Ziehl-Nielsen stain is
gnosis used to demonstrate the
The organism does not have the presence of the bacilli in a
atment
characteristics of either Gram positive or smear. Note the bright red
vention and control negative bacteria. It has a peculiar cell wall
ction 4 quiz that consists of peptidoglycan and complex rods in this sputum smear.
ormation sources lipids. Once stained (e.g. with carbol
mmative assessment fuchsin), the organism will retain dyes when
treated by acidified organic compounds.
Therefore, it is classified as an “acid–fast”
bacterium.

demiology 3

Microbiology (2) Partners in Global Health Education

The cell wall is a major factor in the virulence of the organism.
arning outcomes
It resists destruction by many
at is TB? antibiotics, acids, alkalis, osmotic
demiology lysis and oxidation and enables
robiology the organism to survive and
nsmission multiply within macrophages.
ction 1 quiz
ural history
ction 2 quiz
M. tuberculosis grows in
mptoms and signs Lowenstein Jensen medium, an
ction 3 quiz egg-based medium, which
gnosis contains inhibitors to keep
atment contaminants from outgrowing the
vention and control organism. Because of its slow
ction 4 quiz growth, it takes 4-6 weeks before Typical small, buff coloured colonies of
M. tuberculosis on Lowenstein Jensen
ormation sources small buff-coloured colonies are medium
mmative assessment visible on the medium.

Transmission 1

How is TB transmitted? Partners in Global Health Education

w to use this module Nearly all TB infection is acquired by inhalation of respiratory
arning outcomes
droplets from people with TB in the lungs or throat.
at is TB?
demiology
robiology
Air droplets 3-5 μm
nsmission diameter are coughed,
ction 1 quiz sneezed or spat-out by an
ural history
ction 2 quiz
“open” case of TB. The
mptoms and signs droplets are inhaled by a
ction 3 quiz close contact. This is
gnosis
atment
more likely to occur in
vention and control overcrowded
ction 4 quiz environments.
ormation sources
mmative assessment

NB. Abdominal TB can also result from drinking unpasteurised
cow’s milk infected with M. bovis.

End of Section 1 Partners in Global Health Education

arning outcomes Well done!
You have come to the end of the first section.
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
mptoms and signs
ction 3 quiz
gnosis
atment
vention and control

We suggest that you answer questions 1 to assess your
ction 4 quiz
ormation sources
mmative assessment learning so far. Please remember to write your answers on
the mark sheet before looking at the correct answers!

Question 1: Risk of exposure to TB
Write “True” or “False” on the answer sheet.
When you have completed all 5 questions, click on the boxes and mark your answers.

Now that you know how TB is transmitted, are the following
arning outcomes people at increased risk of exposure?
Click for the correct
at is TB?
answer
demiology
robiology
nsmission
a) Close contacts of people with open TB (e.g. a
ction 1 quiz family members)
ural history
ction 2 quiz b) People who drink unpasteurised milk b
mptoms and signs
c) People living in poor, overcrowded
ction 3 quiz
c
gnosis
atment
environments
vention and control d) People who work or are residents in long- d
ction 4 quiz
ormation sources term facilities
mmative assessment
e) Infants and young children e

Pathogenesis 1

What happens following inhalation of M. tuberculosis?

Outcome 1: No infection Partners in Global Health Education

w to use this module Between 70-90% of individuals exposed to TB will not
arning outcomes
at is TB?
develop the infection.
demiology
robiology The reasons for this are unclear. However, in view of the
nsmission
ction 1 quiz
known risk factors for infection, people who inhale
ural history bacilli but do not develop an infection may:
ction 2 quiz
mptoms and signs
• inhale too few organisms to cause infection
ction 3 quiz
gnosis
• have sufficient immunity to prevent an infection
atment becoming established
vention and control
ction 4 quiz
ormation sources Any factor associated with impaired immunity, such as
mmative assessment extremes of age, malnutrition and HIV/AIDS will
increase the risk of developing infection.

Pathogenesis 2


Outcome 2: Infection with formation of a primary complex Partners in Global Health Education

Following inhalation, tubercle bacilli settle in the alveoli
w to use this module and result in local inflammation in the lung
arning outcomes parenchyma. This “primary focus” usually occurs in
at is TB? the upper lobes in adults but may occur in any of the
demiology lung lobes in children. More than one focus may occur
robiology in the same patient.
nsmission
ction 1 quiz
The organisms then spread via the local lymphatics to
the nearest hilar lymph nodes, which may then
ural history
enlarge.
ction 2 quiz
mptoms and signs
The primary focus and the enlarged regional lymph
ction 3 quiz
nodes form the “primary complex” or “Ghon
gnosis complex”. Primary focus successfully
atment contained by the host immune
vention and control What happens next depends on the size of the system
ction 4 quiz infecting dose and the resistance of the host. Most
ormation sources commonly, the primary focus is “walled-off” by the The person is infected but does not
immune system and lies dormant– “latent TB”. The have TB disease and cannot
mmative assessment
infection may be reactivated years later if the immune spread TB. However, an immune
system of the host becomes weakened. response to M. tuberculosis will
have developed – and can be
demonstrated by a positive
Mantoux test (see later).

athogenesis 3


Outcome 3: Pulmonary disease Partners in Global Health Education

If the primary focus is not contained, lung disease may
develop in several ways:
arning outcomes
• The primary focus enlarges and undergoes central
at is TB?
necrosis to form a cavity
demiology
• The infection can spread locally and result in
robiology
tuberculous bronchopneumonia
nsmission
• Marked swelling of the mediastinal lymph nodes may
ction 1 quiz
compress large bronchi and result in lobar collapse
ural history
ction 2 quiz
• The enlarged lymph node may act like a one-way
valve causing hyperinflation of a lung or lobe
mptoms and signs
ction 3 quiz
• The adjacent pleura can become infiltrated by M.
gnosis
tuberculosis resulting in a hypersensitivity reaction
characterised by granulomas composed mainly of
atment
lymphocytes Infection not contained by
vention and control
• Pleural infiltration may result in a pleural effusion the immune system.
ction 4 quiz
which is rich in lymphocytes – a useful pointer to the Person develops lung
ormation sources
diagnosis when pleural fluid is aspirated and disease and becomes an
mmative assessment
analysed open case - capable of
• Long term complications of the damage to lung infecting others via
tissue include emphysema and bronchiectasis respiratory droplets.

Pathogenesis 4

Outcome 4: Systemic disease Partners in Global Health Education

Haematogenous dissemination of M.
w to use this module tuberculosis leads to granuloma formation in
arning outcomes many organs. Examples include:
at is TB?
demiology
robiology • Diffuse infection of the lungs: “miliary” TB
nsmission • Brain: TB brain abscess
ction 1 quiz
• Meninges: TB meningitis
ural history
ction 2 quiz • Bones: TB osteomyelitis – commonly affects
mptoms and signs the spine and is then called “Potts’ disease”
ction 3 quiz • Pericardium: TB pericarditis and pericardial
gnosis
atment
effusion
vention and control
ction 4 quiz As with acquiring infection after inhalation,
ormation sources
disseminated disease is most likely to occur in
mmative assessment
the immunocompromised person (e.g.
HIV/AIDS, malnutrition) and at extremes of age.

Pathogenesis 5

Summary (1): natural history following TB
exposure

What are the likely outcomes following exposure to open TB?
arning outcomes
at is TB?
Exposure to TB
demiology
robiology
nsmission
ction 1 quiz
ural history
No infection Infection
ction 2 quiz
mptoms and signs
(70-90%) (10-30%)
ction 3 quiz
gnosis
atment Dormant TB (90%) Active TB (10%)
vention and control • well • ill and likely to die if
ction 4 quiz
• no TB disease untreated
ormation sources
• not infectious to • infectious
mmative assessment
others
Activation of infection
results in disease

Pathogenesis 1

Summary (2): natural history following TB exposure

arning outcomes
at is TB? There are 4 possible outcomes following inhalation of TB bacilli:
demiology
robiology
nsmission
Outcome Person Person Person develops
ction 1 quiz
unwell? transmits an immune
ural history
disease? response to TB?
ction 2 quiz
1: No infection No No No
mptoms and signs
ction 3 quiz
2. 1o lung complex No No Yes
gnosis
atment 3. Pulmonary disease Yes Yes Yes
vention and control
ction 4 quiz 4: Systemic disease Yes Yes Yes
ormation sources
mmative assessment

Note: outcomes 3 and 4 can develop many years after formation of the 1 o lung
complex


arning outcomes Well done!
You have come to the end of the second section.
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
mptoms and signs
ction 3 quiz
gnosis
atment
vention and control

Answer questions 2 through 4 to assess your learning so
ction 4 quiz
ormation sources
mmative assessment far. Challenge yourself: complete the mark sheet before
looking at the correct answers!

Question 2: Groups of people at increased risk of TB disease
and disseminated infection following exposure are:

Click for the
correct answer

arning outcomes
at is TB? a) Infants and children <5 years a
demiology
robiology
nsmission b) People with HIV/AIDS b
ction 1 quiz
ural history
c) People with diabetes mellitus, measles,
ction 2 quiz
mptoms and signs
c
ction 3 quiz
pertussis or on prolonged corticosteroid therapy
d
gnosis
atment
vention and control
d) Young adults
ction 4 quiz
ormation sources
e) Alcoholics and IV drug users e
mmative assessment

Question 3: Factors underlying the resurgence of TB in
the last 2 decades are:
Write “True” or “False” on the answer sheet. Partners in Global Health Education

Click for the
correct answer
arning outcomes
at is TB? a) HIV pandemic a
demiology
robiology
nsmission b) Poverty/worsening socioeconomic conditions b
ction 1 quiz
ural history
ction 2 quiz c) Poor hygiene c
mptoms and signs
ction 3 quiz
gnosis
d) Emergence of drug resistance strains d
atment
vention and control
ction 4 quiz
e) Poor national TB control programmes e
ormation sources
mmative assessment

Question 4: Following exposure to M. tuberculosis

Click for the
correct answer
arning outcomes
a) The usual outcome is a primary
at is TB?
infection a
demiology
robiology
nsmission b) The primary complex consists of a b
ction 1 quiz cavity in the lung parenchyma and
ural history hilar lymphadenopathy
ction 2 quiz
mptoms and signs
ction 3 quiz
c) A pleural aspirate rich in neutrophils c
gnosis
suggests TB as a cause
atment
vention and control
d) Miliary TB refers to disseminated d
ction 4 quiz
infection spread via the bloodstream
ormation sources
mmative assessment

inical features 1

What are the symptoms and signs of TB?
1. Primary infection with no spread of the disease Partners in Global Health Education

Individuals with primary infection do not
arning outcomes usually have any symptoms or signs of ill
at is TB?
health although some people develop a Erythema nodosum:
demiology
robiology minor flu-like illness. ecchymotic papules found
nsmission
along the shin or on the
ction 1 quiz Infection triggers an immune response flexural surfaces of the limbs
ural history and, in a minority of people, this may
ction 2 quiz Phlyctenular
mptoms and signs
result in clinical signs of hypersensitivity keratoconjunctivitis: raised,
yellowish nodule at the
ction 3 quiz to M. tuberculosis for example: corneoscleral junction. Small
gnosis
blood vessels may be seen
atment • erythema nodosum radiating from the nodule.
vention and control
ction 4 quiz • phlyctenular keratoconjunctivitis
ormation sources
mmative assessment They will also have a positive Mantoux
test (see below).

cal features 2

2. Active infection: symptoms Partners in Global Health Education

Symptoms of TB can be divided General symptoms
into general symptoms and those • Fever
arning outcomes
specific to the organ infected. • Loss of weight in adults or growth
at is TB?
faltering in children
demiology
TB can result in a myriad of • Night sweats
robiology
nsmission
symptoms depending on which • Malaise, tiredness and anorexia
ction 1 quiz organs are involved and how their
Organ specific - examples include:
ural history function is affected.
ction 2 quiz
The lung is the predominant Lungs
mptoms and signs
• Cough – usually chronic (lasting >6
ction 3 quiz organ affected, being involved in weeks)
gnosis over 75% of cases. • Productive of whitish or mucoid sputum
atment in adults but usually unproductive in
children
vention and control Commonly affected organs • Haemoptysis (coughing-up blood)
ction 4 quiz following haematogenous spread
ormation sources
from the lung are the abdomen, Central Nervous System
mmative assessment • TB meningitis
lymph nodes, spine, meninges,
• Tuberculoma, with the classical features
kidneys, bone and reproductive of a space-occupying lesion simulating a
organs. brain tumour

cal features 3

2. Active infection: signs Partners in Global Health Education

w to use this module General examination - look for:
arning outcomes
at is TB?
• fever
• signs of malnutrition signifying a chronic illness
demiology
• enlargement of the peripheral lymph nodes
robiology
• digital clubbing as a consequence of chronic
nsmission
infection/inflammation in the chest or abdomen
ction 1 quiz
ural history
ction 2 quiz TB lymphadenitis presents as painless
mptoms and signs enlargement of the superficial lymph nodes. The
ction 3 quiz neck is the commonest site involving the cervical,
gnosis submandibular, pre and post-auricular lymph
atment
nodes. The lymph nodes are non-tender, matted
vention and control
together and rubbery in consistency. It is
common for enlarged lymph nodes to ulcerate
ction 4 quiz
and discharge.
ormation sources
mmative assessment
Look at this picture of a 4 year old boy from West
Africa. Note that he is generally wasted and has
marked enlargement of the cervical lymph nodes
– especially on the right side.

cal features 3

3. Pulmonary and abdominal TB Partners in Global Health Education

Pulmonary TB (PTB)

w to use this module The apical region is the most
arning outcomes commonly affected in adults.
at is TB? Pulmonary lesions may involve any
demiology part of the lung in infancy and
robiology childhood.
nsmission
ction 1 quiz Abnormalities detected clinically
ural history
include consolidation, collapse,
pleural effusion and fibrosis. But
ction 2 quiz
beware: examination of the
mptoms and signs
respiratory system may be
ction 3 quiz
completely normal even in active
gnosis
disease! Upper lobe changes on CXR
atment
Source: WHO/TBP/Pierre Virot
vention and control Abdominal TB
ction 4 quiz
ormation sources Pathology affects the mesenteric and the retroperitoneal glands, the omentum and
mmative assessment the gastrointestinal tract. Patients may present with weight loss, diarrhoea or
constipation, abdominal distension (from ascites) or chronic intestinal obstruction.
Enlarged mesenteric lymph nodes may be palpable as multiple intra-abdominal
masses.

Tuberculosis of the spine – “Pott’s disease”

TB commonly affects the spine,
arning outcomes especially in young children, and
at is TB? usually presents as a swelling on the
demiology back.
robiology
nsmission
The lower thoracic and the upper
lumbar vertebrae are the usual sites,
ction 1 quiz
however any vertebra can be
ural history affected.
ction 2 quiz
mptoms and signs The patient may also present with
ction 3 quiz
kyphosis, scoliosis, kyphoscoliosis,
or features of spastic paraparesis.
gnosis
There may be a sharp angulation of
atment the spine caused by collapse of a
vention and control vertebra – referred to as a “gibbus”
ction 4 quiz
ormation sources
mmative assessment A young child from West
Africa. Note the swelling over
the lower thoracic vertebrae.


Well done!
arning outcomes
at is TB? This is the end of the second section.
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
mptoms and signs
ction 3 quiz
gnosis
atment
vention and control We suggest that you proceed to answer question 5 to
ction 4 quiz
assess your learning further. Do remember to write your
ormation sources
answers on the mark sheet before looking at the right
mmative assessment
answer!

Clinical features
Quiz 1

Question 5: What 2 features are consistent with
pulmonary TB in this man? Partners in Global Health Education

arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
Write Down Your
ction 2 quiz
Answers on your
mptoms and signs mark sheet, then
ction 3 quiz click below to reveal
gnosis
the answers
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment
Man with advanced TB in Bangladesh
source: WHO/TBP/England
Click to Reveal Answers

Investigation 1

Diagnosis Partners in Global Health Education

In developing countries, the diagnosis
w to use this module of TB is based on the combination of
arning outcomes clinical assessment and simple
at is TB?
laboratory methods:
demiology
robiology 1. History of chronic cough with the
nsmission general symptoms of fever, malaise
ction 1 quiz
and weight loss
ural history
2. Presence of general and specific
clinical signs
ction 2 quiz
3. Positive findings on relevant
mptoms and signs
investigations – usually CXR and
ction 3 quiz sputum smear stained for acid-fast
gnosis bacilli
atment
Examining a CXR in China
vention and control It is important to note that specific Source: WHO/TBP/Pierre Virot
ction 4 quiz symptoms and signs may be absent.
ormation sources
mmative assessment

TB should be suspected in any chronically ill person!

Investigation 4

Bacteriological diagnosis

• Sputum microscopy is most useful in
adults with a productive cough. A sputum
smear is stained with the Ziehl-Nielsen
arning outcomes stain to demonstrate the presence of the
at is TB? acid and alcohol fast bacilli (AFB). When
demiology
positive, the patient is “smear-positive” or
“open TB” and the risk of transmission of
robiology
infection to others is very high. However,
nsmission the test is often falsely negative in patients
ction 1 quiz with TB. The yield of the test is higher in
ural history
patients with lung cavities.
ction 2 quiz
mptoms and signs • Gastric washings examined for AFB:
ction 3 quiz
Carried out in children as they swallow
rather than cough-up sputum. The test
gnosis aims to recover the swallowed AFB from
atment the stomach using a naso-gastric tube. The
vention and control test is positive in only about one third of
ction 4 quiz
children with TB. Sputum samples collected in a
ormation sources health facility in Ethiopia
mmative assessment
• Bacterial culture: This takes about 6-8 source: WHO/TBP/Jan Van den
weeks and so is of limited use in clinical Hombergh
diagnosis. M. tuberculosis grows on a
special medium called the Lowenstein
Jensen medium.

Investigation 5

Mantoux or tuberculin skin test

This test detects a delayed hypersensitivity, cutaneous reaction to a purified
protein derivative (PPD) of M. tuberculosis – also called “tuberculoprotein”:
arning outcomes
at is TB?
1. PPD is injected intradermally
demiology
2. the injection site is inspected 48-72 hours later
robiology 3. erythema and induration at the site signify an immune response and,
nsmission
therefore, previous exposure to mycobacteria
ction 1 quiz
ural history The limitations of this test are well-known:
ction 2 quiz  False positive: a skin reaction in people who do not have TB because of
mptoms and signs
exposure to non-pathogenic mycobacteria and also due to the immune
response following BCG immunisation (see later).
ction 3 quiz
 False negative: a negative result in a person with TB in early primary
gnosis
infection or because they are immunocompromised – for example, due to
atment HIV/AIDS, malnutrition or people who develop disseminated TB.
vention and control
ction 4 quiz
In general, the greater the degree of erythema and induration, the more likely
ormation sources the patient has TB disease. Several detailed criteria are available to guide
mmative assessment the interpretation of Mantoux results, e.g. from the American Thoracic
Society and Centers for Disease Control & Prevention

nvestigation 7

Diagnosis: Other investigations Partners in Global Health Education

Other investigations are indicated depending on the organs/ systems
affected by the disease
arning outcomes
at is TB?
 Spinal radiographs in Pott’s disease
demiology  Lymph node aspirate (microscopy, culture and cytology) or biopsy
robiology (histology and culture) in TB lymphadenitis
nsmission
ction 1 quiz
 Lumbar puncture for cerebrospinal fluid analysis in TB meningitis
ural history
(microscopy, biochemical analysis and culture)
ction 2 quiz
mptoms and signs
A recent development is the detection of the growth of TB in liquid
ction 3 quiz
culture by microscopy. Diagnosis can be made within 10 days and
gnosis
addition of drugs to the cultures allows the detection of drug
atment
resistance.*
vention and control
ction 4 quiz Also, a number of new diagnostic tests have been developed based
ormation sources on molecular methods such as the amplification of nucleic-acid.
mmative assessment
However, these assays have not been fully evaluated and are
expensive.

* Moore DA et al. Microscopic-observation drug-susceptibility assay for the diagnosis of
TB. N Engl J Med 2006; 355:1539-50

Treatment Partners in Global Health Education

Resistance of M. tuberculosis to antimicrobials is a major
arning outcomes
problem in TB treatment. Because it is a slow growing
at is TB? organism, treatment courses are long - at least 6 months.
demiology
robiology
nsmission
• Treatment requires a
ction 1 quiz
combination of drugs to which
ural history
the organisms are sensitive.
ction 2 quiz
mptoms and signs • Treatment courses must be
ction 3 quiz completed for effective cure
gnosis and to prevent the emergence
atment of drug-resistant strains.
vention and control
ction 4 quiz
• Longer treatment courses are
ormation sources
mmative assessment
needed for TB meningitis or if Combination antibiotic therapy
the bacteria are resistant and in India
Source: IUTBLD WHO/TBP/Gary
additional drugs are required. Hampton

Management

Treatment: DOTS Partners in Global Health Education

DOTS is the acronym for Directly Observed Treatment Short Course.
arning outcomes
It involves the daily administration of a combination of antituberculous drugs to
at is TB?
a TB patient under the supervision of a healthcare personnel. DOTS helps to
demiology ensure compliance, reduce transmission by shortening the period of infectivity,
robiology improve the cure rate and reduce the risk of drug resistance.
nsmission
ction 1 quiz There are many regimens for treating TB. The most frequently recommended
ural history regimen that is also effective in people with HIV infection is:
ction 2 quiz
mptoms and signs Drug 0-2 months 3-6 months
ction 3 quiz
gnosis
Isoniazid + +
atment Rifampicin + +
vention and control
Pyrazinamide + -
ction 4 quiz
ormation sources Ethambutol* + -
mmative assessment

*IM streptomycin is often substituted for oral ethambutol for children < 6 years

Drug-resistant TB

There are 2 classes of drug resistant TB:
arning outcomes
at is TB?
1. Multidrug-resistant (MDR)
demiology • defined as resistance to rifampicin and isoniazid, +/- other
robiology drug resistance
nsmission • worldwide, >4% of TB patients are MDR, with the highest
ction 1 quiz prevalence in Eastern Europe
ural history • treatment requires longer drug regimens, is less effective,
ction 2 quiz more costly and poorly tolerated
mptoms and signs
ction 3 quiz
gnosis
2. Extensively drug-resistant (XDR)
atment
• defined as resistance to rifampicin and isoniazid and, in
vention and control
addition, resistance to any quinolone and at least on
ction 4 quiz
injectable second-line drug
ormation sources • XDR TB is essentially untreatable and has a very high
mmative assessment mortality

ention

Prevention and Control

TB control strategies include –
w to use this module • Case finding: aims to identify TB cases promptly, treat them
arning outcomes with an effective combination of drugs and ensure that the
at is TB? course is completed.
demiology
robiology
• Contact tracing: Close contacts of TB cases are screened for
nsmission
evidence of infection. Mantoux positive cases are treated with
ction 1 quiz
oral isoniazid for 6-12 months to prevent them from developing
ural history
the disease. This regimen is also used in HIV-positive people.
ction 2 quiz
mptoms and signs
ction 3 quiz
• Bacillus Calmette-Guérin (BCG) vaccine
gnosis • contains an attenuated strain of M. bovis
atment • is administered as a single intradermal injection
vention and control
• Has limited efficacy against pulmonary TB (and, therefore,
ction 4 quiz
TB transmission) but does appear to prevent disseminated
ormation sources disease and death – especially in children
mmative assessment
• is given routinely to infants in developing countries and to
people at increased risk of TB infection in developed
countries

TB: the future Partners in Global Health Education

WHO declared TB a global health emergency in 1993 and aims to
w to use this module eliminate TB as a public health problem by 2050.
arning outcomes
• Other organisations involved in TB
at is TB?
control include the International Union
demiology Against TB and Lung Disease, the
robiology Center for Disease Control (USA) and
nsmission the Global Plan to Stop TB.
ction 1 quiz
• TB remains a worldwide challenge.
ural history
There is a need to improve DOTS
ction 2 quiz
coverage and meet the emerging
mptoms and signs challenges of TB in people with
ction 3 quiz HIV/AIDS and multidrug resistant TB.
gnosis
• Improved techniques for diagnosis are
atment
required especially in people with
vention and control
compromised immunity where diagnosis
ction 4 quiz
is difficult such as HIV/AIDS and
ormation sources malnourished children.
mmative assessment
• A more effective vaccine and improved
treatment strategies that would decrease
the duration of treatment are also high IUATLD; WHO/TBP/Falise
priorities.


You have come a long way!
arning outcomes
at is TB? This is the last of the sections.
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
mptoms and signs
ction 3 quiz
gnosis
atment
vention and control
ction 4 quiz
For the section just ended, you should be able to answer
ormation sources Questions 6 - 8 to assess what you have learnt. It is still
mmative assessment required that you put down your answers on the mark
sheet before looking at the right answer!

Question 6: A person with latent TB

Click for the
correct answer
arning outcomes
at is TB? a) Is infectious to other people a
demiology
robiology
nsmission b) Feels well b
ction 1 quiz
ural history
ction 2 quiz c) Tuberculin skin test is positive c
mptoms and signs
ction 3 quiz
gnosis d) Can not develop TB later in life d
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Question 7: The following are recognised
manifestations of TB Partners in Global Health Education

Click for the
correct answer
arning outcomes
at is TB?
a) Pericarditis a
demiology
robiology
nsmission
b
ction 1 quiz
ural history
b) Meningitis
ction 2 quiz
mptoms and signs
c
ction 3 quiz
gnosis
c) Erythema nodosum
atment
vention and control
d
ction 4 quiz
ormation sources
d) Osteomyelitis
mmative assessment

e) Phlyctenular conjunctivitis e

Question 8: The following are indicated in the
management of miliary TB Partners in Global Health Education

Click for the
correct answer
arning outcomes
at is TB?
demiology
a) High protein diet a
robiology
nsmission
ction 1 quiz b) BCG Vaccination b
ural history
ction 2 quiz
mptoms and signs
ction 3 quiz
c) Contact tracing c
gnosis
atment
vention and control
ction 4 quiz
d) Isoniazid prophylaxis for 6-12 d
ormation sources months
mmative assessment

e
e) Lumbar puncture

Sources of information / bibliography

You can copy and paste the links below into your browser to access
w to use this module the resources:
arning outcomes
at is TB? • Maartens G, Wilkinson RJ. Tuberculosis. The Lancet 2007; 370:2030-
demiology 43
robiology
• Diagnostic atlas of intra-thoracic tuberculosis in children; A guide for
nsmission Low Income Countries. Dr. Robert Gie, International Union against
ction 1 quiz Tuberculosis and Lung Disease (IUATLD) 2003. Available at:
ural history http://www.iuatld.org
ction 2 quiz • The Division for Tuberculosis Elimination, Centre for Disease Control
mptoms and signs (CDC), Atlanta, USA http://www.cdc.gov/nchstp/tb/faqs/qa.htm
ction 3 quiz
• Stop TB Partnership; http://www.stoptb.org/
gnosis
atment
• WHO – several information resources available at
http://www.who.int/tb/en/
vention and control
ction 4 quiz • Treatment guidelines: http://www.Nice.ac.uk
ormation sources • TB in the UK: http://www.Hpa.org.uk
mmative assessment


w to use this module Summative assessment
arning outcomes
at is TB?
demiology
robiology
nsmission
• Well done! We hope that you enjoyed
ction 1 quiz completing this module.
ural history
ction 2 quiz
mptoms and signs
• Now try the summative assessment
(available from
ction 3 quiz
gnosis
atment
http://www.medicine.swansea.ac.uk/inthealth.html)
vention and control
ction 4 quiz
ormation sources • … and good luck!
mmative assessment

Authors and reviewers Partners in Global Health Education

Authors: Expert reviewers:
arning outcomes Dr. Ike Lagunju, Consultant We would like to thank the following
at is TB? Paediatrician and Lecturer, College people for reviewing this module:
demiology of Medicine, University of Ibadan,
Ibadan, Nigeria.
robiology
At the College of Medicine, University of
nsmission
Ibadan, Ibadan, Nigeria
ction 1 quiz Dr. David Lewis, Learning
Technologist, The School of • Professor Olugbemiro Sodeinde
ural history Medicine, Swansea University, • Professor Kikelomo Osinusi
ction 2 quiz Swansea, UK
mptoms and signs
• Professor Adegoke Falade
ction 3 quiz Dr. Stephen Allen, Professor of
gnosis Paediatrics and International At the School of Medicine, Swansea
atment Health; The School of Medicine, University, Swansea, UK
Swansea University, Swansea, UK
vention and control • Professor Julian Hopkin
ction 4 quiz • Dr Gwyneth Davies
ormation sources
mmative assessment

We would like to acknowledge the of the Association of Commonwealth
Universities, London for awarding the Fulton Fellowship which supported Dr.
Lagunju in developing this module

Back


arning outcomes
Answer to question 1a
at is TB?
demiology

This statement is True.
robiology


nsmission
ction 1 quiz
ural history People with open TB produce TB bacilli in
ction 2 quiz
mptoms and signs their respiratory droplets. This exposes
ction 3 quiz
gnosis their close contacts to the organism.
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
Answer to question 1b
demiology
robiology
nsmission
ction 1 quiz
ural history This statement is True.
ction 2 quiz


mptoms and signs Tubercle bacilli are not only acquired by
ction 3 quiz
gnosis respiratory droplets. M. bovis may be acquired by
atment
vention and control ingestion of infected unpasteurised cow’s milk.
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
Answer to question 1c
demiology
robiology
nsmission
ction 1 quiz
ction 2 quiz

 In overcrowded and poorly ventilated
mptoms and signs
ction 3 quiz
gnosis
environments, all diseases that are transmitted
atment
vention and control
by respiratory droplets are easily spread.
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
Answer to question 1d
demiology
robiology
nsmission
ction 1 quiz
ction 2 quiz

 Prolonged contact and exposure in
mptoms and signs
ction 3 quiz
gnosis
overcrowded, low resource institutions (e.g.
atment
vention and control
some hospitals and prisons) increases the risk
ction 4 quiz
ormation sources
of acquiring TB.
mmative assessment

Back


arning outcomes
at is TB?
Answer to question 1e
demiology
robiology
nsmission This statement is False.
ction 1 quiz
ural history
ction 2 quiz
Tuberculosis affects all age groups. Infants

 and young children not residing in overcrowded
mptoms and signs
ction 3 quiz
gnosis
environments will not have an increased risk of
atment
vention and control
exposure. You will learn about factors which
ction 4 quiz
ormation sources
favour disease progression after exposure
mmative assessment

shortly.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
Infants and young children, and also the


mptoms and signs
ction 3 quiz
elderly, are more likely than young and middle-
gnosis
atment
aged adults to develop an infection and
vention and control
ction 4 quiz
progress to disseminated disease when
ormation sources
mmative assessment
exposed to the bacillus. This is thought to be
due to an immature or weakened immune
system.
Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ction 2 quiz

 People with HIV/AIDS have depressed
mptoms and signs
ction 3 quiz
gnosis
immunity. Therefore, they are more likely to
atment
vention and control
acquire TB when exposed and also to develop
ction 4 quiz
ormation sources
disseminated infection. An annual incidence of
mmative assessment

TB as high as 30% has been reported in
clinically advanced HIV.
Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ction 2 quiz


mptoms and signs People with these conditions are likely to be
ction 3 quiz
gnosis immunocompromised putting them at increased
atment
vention and control risk. Also, those with silicosis and other
ction 4 quiz
ormation sources conditions that compromise lung function are
mmative assessment
also at increased risk if exposed.

Back


arning outcomes
at is TB?
demiology
robiology

This statement is False.
nsmission
ction 1 quiz
ural history
ction 2 quiz 70% - 90% of individuals will not develop any


mptoms and signs
ction 3 quiz infection following exposure. In healthy young adults
gnosis
atment who do develop a primary TB focus, a competent
vention and control
ction 4 quiz
immune system “walls-off” the lesion and prevents it
ormation sources
mmative assessment
from spreading. Such people do not develop disease
and do not spread TB.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz


ction 2 quiz
mptoms and signs
Many factors present in alcoholics and IV drug
ction 3 quiz
gnosis
users, such as poor nutritional status and
atment
vention and control
frequent other infections, tend to impair
ction 4 quiz
ormation sources
immunity and increase the risk of TB disease.
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
The correct answer is True: The HIV


ural history
ction 2 quiz
mptoms and signs
pandemic has caused an increase in the number of
ction 3 quiz
gnosis
people susceptible to disseminated TB. The high
atment
vention and control
number of HIV-infected people in sub-Saharan
ction 4 quiz
ormation sources
Africa is a major factor that underlies the increasing
mmative assessment
annual incidence of TB in this region.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
The correct answer is True: Poverty and


ction 2 quiz
mptoms and signs
ction 3 quiz poor socioeconomic conditions are associated with
gnosis
atment factors such as overcrowding and poor nutrition that
vention and control
ction 4 quiz increase transmission and susceptibility to TB.
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
The correct answer is False: Hygiene


ction 2 quiz
mptoms and signs
ction 3 quiz has no direct bearing on the transmission of TB.
gnosis
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
The correct answer is True: The


ction 2 quiz
mptoms and signs
emergence of strains of TB that are resistant to the
ction 3 quiz
gnosis
commonly-available drugs means that open cases
atment
vention and control
are more difficult to treat. Therefore, these people
ction 4 quiz
ormation sources
continue to spread infection through respiratory
mmative assessment
droplets. More information about drug-resistant TB
is provided later in this module.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
The correct answer is True: Factors


ction 2 quiz
mptoms and signs
such as conflict and inadequate resources and
ction 3 quiz
gnosis
political will weaken control programmes. TB
atment
vention and control
transmission increases in these circumstances.
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz
The answer is False: the majority of


mptoms and signs
ction 3 quiz
people exposed to TB do NOT develop symptoms
gnosis
atment
or show any signs of infection
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology

The correct answer is False: the
nsmission
ction 1 quiz
ural history
ction 2 quiz primary complex consists of the primary focus and


mptoms and signs
ction 3 quiz hilar lymphadenopathy. This occurs when a
gnosis
atment competent immune system contains the infection.
vention and control
ction 4 quiz A cavity results from local spread of the primary
ormation sources
mmative assessment focus with central necrosis.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
ction 2 quiz The correct answer is False: both the


mptoms and signs
ction 3 quiz pleural inflammation and the resultant effusion are
gnosis
atment characterised by lymphocyte infiltration
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
ction 1 quiz
ural history
The correct answer is True: miliary TB


ction 2 quiz
mptoms and signs
ction 3 quiz refers to the characteristic features on CXR
gnosis
atment signifying dissemination of infection.
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
Answer to question 5
demiology
robiology
nsmission
ction 1 quiz
1. He is markedly wasted suggesting a chronic
ural history
illness
ction 2 quiz
mptoms and signs 2. There is clear evidence of poverty – even from
ction 3 quiz this limited view of the health facility
gnosis
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission
The answer is False: A person with
ction 1 quiz
ural history latent TB has TB infection. However,
ction 2 quiz

 the infection is walled-off in the lung
mptoms and signs
ction 3 quiz
gnosis
atment
vention and control
and they are not producing infected
ction 4 quiz
ormation sources
mmative assessment
respiratory droplets. They are not an
“open case”.
Back


arning outcomes
at is TB?
demiology
robiology
nsmission This statement is True. People with latent
ction 1 quiz
ural history TB usually have no symptoms.
ction 2 quiz


Occasionally, they have manifestations of
mptoms and signs
ction 3 quiz
gnosis
atment an immune response to M. tuberculosis
vention and control
ction 4 quiz such as erythema nodosum or phlyctenular
ormation sources
mmative assessment
keratoconjunctivitis.

Back


arning outcomes
at is TB?
demiology
robiology
nsmission This statement is True. As in the last
ction 1 quiz
ural history question, people with latent TB will have
ction 2 quiz


developed an immune response to M.
mptoms and signs
ction 3 quiz
gnosis
atment tuberculosis. Therefore, they will develop
vention and control
ction 4 quiz redness and induration at the site of PPD
ormation sources
mmative assessment
injection.

Back


arning outcomes
at is TB?
demiology
robiology The answer is False: The dormant primary
nsmission
ction 1 quiz
ural history
complex in latent TB can become activated.
ction 2 quiz
This may occur many years after TB


mptoms and signs
ction 3 quiz
gnosis infection occurred. It occurs when the
atment
vention and control
ction 4 quiz
person’s immune system is compromised,
ormation sources
mmative assessment for example, by malnutrition or steroid
treatment.

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history Correct, this statement is True. Tuberculous
ction 2 quiz
mptoms and signs pericarditis is a recognised form of the disease.
ction 3 quiz
gnosis
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history The organisms can invade the meninges
ction 2 quiz
mptoms and signs following haematogenous dissemination, thereby
ction 3 quiz
gnosis leading to tuberculous meningitis.
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology
nsmission


ction 1 quiz
ural history Erythema nodosum is not a manifestation of
ction 2 quiz
mptoms and signs tuberculous disease. It is seen in patients with
ction 3 quiz
gnosis tuberculous infection and occurs as a result of
atment
vention and control hypersensitivity to the tuberculoprotein.
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history Tuberculous osteomyelitis is a recognised form of
ction 2 quiz
mptoms and signs the disease. The spine is the commonest site
ction 3 quiz
gnosis involved in TB osteomyelitis.
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology
nsmission


ction 1 quiz
ural history Phlyctenular conjunctivitis is not a manifestation of
ction 2 quiz
mptoms and signs TB disease. Just as it is explained in (c), it is a sign
ction 3 quiz
gnosis of TB infection and an allergic reaction to the
atment
vention and control tuberculoprotein. It does not signify the presence of
ction 4 quiz
ormation sources the disease.
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history Most patients with miliary TB are malnourished
ction 2 quiz
mptoms and signs and so nutritional rehabilitation is an essential
ction 3 quiz
gnosis aspect of their management.
atment
vention and control
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology
nsmission


ction 1 quiz
ural history There is no indication for BCG vaccination after a
ction 2 quiz
mptoms and signs patient has developed the disease! BCG is given
ction 3 quiz
gnosis as part of routine childhood immunisation in some
atment
vention and control countries and helps to prevent life-threatening
ction 4 quiz
ormation sources forms of TB.
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history This is very important. Close contacts of the
ction 2 quiz
mptoms and signs patient should be tested for evidence of
ction 3 quiz
gnosis tuberculous infection or disease and managed
atment
vention and control appropriately. This is an important public health
ction 4 quiz
ormation sources measure in the control of TB.
mmative assessment

Back


arning outcomes
at is TB?
demiology
robiology
nsmission


ction 1 quiz
This patient requires treatment with combination
ural history
ction 2 quiz chemotherapy of anti-TB drugs because he has the
mptoms and signs
ction 3 quiz disease. INH prophylaxis is only given to people who have
gnosis
atment
been infected with the tubercle bacilli but do not have the
vention and control
disease. The drug helps to prevent progression to disease.
ction 4 quiz
ormation sources
mmative assessment

Back


arning outcomes
at is TB?
demiology

robiology


nsmission
ction 1 quiz
ural history Lumbar puncture is indicated in all patients with
ction 2 quiz
mptoms and signs miliary TB, as this condition signifies
ction 3 quiz
gnosis haematogenous dissemination and meningeal
atment
vention and control involvement must be excluded.
ction 4 quiz
ormation sources
mmative assessment

Back

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