L3 - Tuberculosis

Question 1

Where are most TB cases found globally?

Answer 1

80% of TB cases occur in low- and middle-income countries.

Question 2

What increases the risk of developing TB in vulnerable populations?

Answer 2

Malnourishment weakens the immune system, increasing susceptibility to TB.

Question 3

How does access to healthcare impact TB outcomes?

Answer 3

Poor access to healthcare, especially in rural populations and among refugees, leads to worse TB outcomes.
50% of refugees are infected with TB but have limited or no treatment options.

Question 4

What historical event contributed to the resurgence of TB?

Answer 4

The collapse of the Soviet Union led to a collapse of healthcare systems, causing a rise in TB cases.

Question 5

What role does HIV/AIDS play in the spread of TB?

Answer 5

HIV/AIDS compromises the immune system, significantly increasing the risk of active TB in infected individuals.

Question 6

How does HIV affect the immune system, increasing TB risk?

Answer 6

HIV infects CD4+ T cells, which are crucial for immune defense.
M. tuberculosis primarily infects macrophages, which need CD4+ T cells for effective intracellular clearance of pathogens.

Question 7

What is the consequence of HIV depleting CD4+ T cells?

Answer 7

Depletion of CD4+ T cells by HIV significantly increases the risk of TB infection and progression to active disease.

Question 8

How does TB treatment impact the life expectancy of an HIV-positive person?

Answer 8

Treating TB can prolong the life of an HIV-infected person by approximately 2 years.

Question 9

What supportive measures improve outcomes before chemotherapy?

Answer 9

Best available treatment
Adequate nutrition
Education on cough etiquette to reduce spread.

Question 10

What is the Tuberculin/Mantoux test?

Answer 10

nvolves injecting dead bacteria and checking for an immune response after 48 hours.

Question 11

What are the limitations of the Mantoux test?

Answer 11

Doesn’t work in HIV patients.
Doesn’t indicate antibiotic resistance.
False positives can occur due to other Mycobacterium species or the BCG vaccine.

Question 12

Why is it difficult to culture M. tuberculosis?

Answer 12

Takes around 2 weeks to grow.
Difficult to identify via Gram staining.

Question 13

What is the name of the PCR assay used for TB testing?

Answer 13

Xpert MTB/RIF

Question 14

What does the Xpert MTB/RIF assay detect?

Answer 14

M. tuberculosis with high specificity.
Rifampicin resistance by identifying mutations in the rpoB gene.

Question 15

How long does the Xpert MTB/RIF test take to provide results?

Answer 15

2 hours

Question 16

Why is Mycobacterium tuberculosis difficult to target for treatment?

Answer 16

Waxy coat: Makes it impermeable to many drugs.
No cell wall: Resistance to cell wall-targeting antibiotics.
Intracellular in macrophages: Requires drugs that penetrate host cells.

Question 17

Why does TB treatment require prolonged duration?

Answer 17

Slow growth rate: Treatment must last 6 months to 2 years.

Question 18

What challenge arises from prolonged TB treatment?

Answer 18

Non-compliance: Patients may stop treatment prematurely, leading to resistance development.

Question 19

How does TB survive in difficult conditions?

Answer 19

Survives in necrotic tissue with poor vascularization, making drug delivery less effective.

Question 20

What is the purpose of Direct Observed Treatment (DOTs)?

Answer 20

To address compliance issues with TB treatment, which lasts 6 months.

Question 21

How is DOTs implemented?

Answer 21

Initial observation: Patient takes medication under supervision at a clinic.
Ongoing observation: A family member or designated person observes daily medication intake.

Question 22

What are the benefits of DOTs?

Answer 22

Cure rate: Up to 95%, even in poor regions.
Prevention of new infections: By curing infectious patients.
Prevention of drug resistance: Reduces cases of MDR-TB (multi-drug-resistant TB) and XDR-TB (extensively drug-resistant TB).

Question 23

Key feature of Isoniazid treatment?

Answer 23

Effective against actively replicating mycobacteria, requiring prolonged treatment.

Question 24

What does Rifampicin target?

Answer 24

Inhibits RNA polymerase, blocking transcription.

Question 25

Is Rifampicin bactericidal or bacteriostatic?

Answer 25

Bactericidal against mycobacteria, Gram-positive, and some Gram-negative bacteria.