Tuberculosis

Question 1

What causes an infection?

Answer 1

Mycobacterium tuberculosis.

Question 2

What is latent TB?

Answer 2

Infection without disease due to persistent immune system containment

Question 3

What is acute TB?

Answer 3

TB which occurs when containment by the immune system (T-cells/mac- rophages) is inadequate.

Question 4

What are the systemic features of TB?

Answer 4

Low-grade fever, anorexia, weight loss, malaise, night sweats, clubbing (bronchiectasis), erythema nodosum.

Question 5

What are the features of pulmonary TB?

Answer 5

cough, pleurisy, haemoptysis (uncommon), pleural effusion

Question 6

What is military TB?

Answer 6

Haematogenous dissemination leads to the formation of discrete foci (~2mm) of granulomatous tissue throughout the lung (‘millet’ seed appearance).

Question 7

How is latent TB diagnosed? (2)

Answer 7

Tuberculin skin testing (TST) = Mantoux test, Interferon-gamma release assays (IGRAS)

Question 8

How is active TB diagnosed? (4)

Answer 8

CXR, Sputum smear and acid-fast staining, sputum culture, Nucleic acid amplification test (NAAT)