Tuberculosis

Question 1

What percentage of TB patients and their households face catastrophic costs?

Answer 1

Around 49%.

Question 2

What is the End TB Strategy target for catastrophic costs?

Answer 2

Zero.

Question 3

What socioeconomic factors are strongly associated with TB incidence?

Answer 3

Low average income levels and undernutrition.

Question 4

What kind of organism is Mycobacterium tuberculosis?

Answer 4

An obligate intracellular bacterium.

Question 5

Where does M. tuberculosis grow?

Answer 5

Inside macrophages.

Question 6

How fast does M. tuberculosis grow in the lab?

Answer 6

6 weeks.

Question 7

How is TB transmitted?

Answer 7

Via airborne droplets <5µm that reach the alveoli.

Question 8

How many droplet nuclei can a single cough produce?

Answer 8

About 3,000.

Question 9

Is brief exposure sufficient to cause infection?

Answer 9

No – generally requires prolonged exposure (e.g., 8+ hours in enclosed space).

Question 10

After inhalation, what are the possible outcomes of M. tuberculosis infection?

Answer 10

Cleared from the body (90%)
Healed with scarring (Ghon focus)
Latent infection
Primary progressive disease (no latency)

Question 11

What kind of immunity is required to control TB?

Answer 11

Strong cell-mediated immunity.

Question 12

Which cytokines are crucial in TB immunity?

Answer 12

IFN-γ and TNF-α.

Question 13

When is the risk of reactivation highest?

Answer 13

In the first few years after infection.

Question 14

What is the biggest risk factor for TB reactivation?

Answer 14

Immunocompromise (up to 100x increased risk).

Question 15

What is the current TB vaccine?

Answer 15

BCG – a modified live strain of M. bovis.

Question 16

What is BCG best at preventing?

Answer 16

Disseminated and meningeal TB in children.

Question 17

What other disease does BCG protect against?

Answer 17

Leprosy.

Question 18

How does latitude affect BCG efficacy?

Answer 18

Efficacy decreases closer to the equator.

Question 19

What are the constitutional symptoms of TB?

Answer 19

Fever, weight loss, night sweats.

Question 20

What are the two main forms of TB?

Answer 20

Pulmonary and extra-pulmonary.

Question 21

Who is more likely to get primary progressive TB?

Answer 21

Children and immunocompromised patients.

Question 22

What are features of primary progressive TB?

Answer 22

Erythema nodosum, lymphatic obstruction, abscesses, miliary disease, TB meningitis.

Question 23

When does post-primary TB typically occur?

Answer 23

Usually within 2–5 years of initial infection.

Question 24

What lung zones are most affected in post-primary TB?

Answer 24

Upper lobes.

Question 25

What are key symptoms of post-primary pulmonary TB?

Answer 25

Chronic cough, haemoptysis, pleural effusions, constitutional symptoms.

Question 26

What is the most common site of extra-pulmonary TB?

Answer 26

Lymph nodes (especially cervical).

Question 27

What are "cold abscesses" in TB?

Answer 27

Painless abscesses often found in lymph node TB.

Question 28

Which part of the spine is most commonly affected in TB?

Answer 28

Thoracic spine.

Question 29

What is Gibbus deformity?

Answer 29

Spinal wedging caused by TB of the spine.

Question 30

What other organs can be affected by extra-pulmonary TB?

Answer 30

Brain, GI tract, kidneys, bones/joints.

Question 31

What methods are used to obtain pulmonary TB samples?

Answer 31

Spontaneous sputum, induced sputum, bronchoscopy.

Question 32

What tests are performed on TB samples?

Answer 32

Smear microscopy, culture, and PCR (molecular detection).

Question 33

What are the 4 first-line drugs for TB?

Answer 33

Isoniazid, Rifampicin, Pyrazinamide, Ethambutol.

Question 34

What is the standard TB treatment regimen?

Answer 34

2 months of RIPE 4 OR 7 months of R+I

Question 35

What is the role of Isoniazid in TB treatment?

Answer 35

Bactericidal – rapidly kills multiplying bacteria.

Question 36

What is the role of Rifampicin?

Answer 36

Bactericidal and sterilising – kills slow-growing bacteria.

Question 37

How quickly do Isoniazid and Rifampicin work?

Answer 37

90% of bacteria dead in 2 days with isoniazid 99% dead in 14 days with rifampicin added

Question 38

What drugs were used in TB treatment in the 1950s–60s?

Answer 38

PAS, Streptomycin, Isoniazid.

Question 39

What major change occurred in the 1960s–70s?

Answer 39

Rifampicin replaced PAS.

Question 40

What drug was added in the 1970s?

Answer 40

Pyrazinamide.

Question 41

When was Ethambutol added as the 4th drug?

Answer 41

In the 1980s.

Question 42

What is the aim of latent TB treatment?

Answer 42

To prevent progression to active TB.

Question 43

What are the 3 main latent TB regimens?

Answer 43

6 months isoniazid 4 months rifampicin 3 months of both

Question 44

How effective is latent TB treatment?

Answer 44

Reduces progression risk by ~90%.

Question 45

What are the key risk factors for MDR/XDR-TB?

Answer 45

Previous incomplete treatment Contact with MDR-TB Origin from high-MDR regions Former Soviet Union, South Africa Prison treatment in the Baltics

Question 46

Why is combination therapy essential in TB?

Answer 46

To prevent resistance and ensure sterilization of infection.