TB

Question 1

What are the stages of TB infection?

Answer 1

Immediate clearance

Primary disease - active disease with symptoms, usually in immunocompromised

Latent- Ceasating granuloma formed with necrotic centre

Reactivation (10% lifetime risk)

Question 2

What are the screening tests for latent TB?

Answer 2

Mannox skin test (induration of more than 5mm is positive)

IGRA blood test (less likely to get false positive)

Question 3

What is the treatment for Latent TB?

Answer 3

Three months of isoniazid (and pyridoxine) and rifampicin
or
Six months of isoniazid (with pyridoxine).

Question 4

What are the suggested tests for TB?

Answer 4

CXR
Culture (gold standard)
acid-fast bacilli stain
NAAT (Rapid testing)

Question 5

What are the chest xray signs?

Answer 5

Primary: Hilary lymphadenopathy, pleural effusions + infiltrates, calcification

Reactivation: Upper love caveatting lesion

Question 6

What is the treatment for active TB?

Answer 6

6 months of isoniazid (with pyridoxine) and rifampicin, supplemented in the first 2 months with pyrazinamide and ethambutol