10. TB

Question 1

What are the risk factors for TB?

Answer 1

Endemic areas
History of TB or exposure
HIV/AIDS or immunosuppression
Overcrowding
Drug use, homelessness
TNF inhibitors

Question 2

How is TB spread?

Answer 2

Droplets

Question 3

What factors in a history cause a suspicion of TB?

Answer 3

Cough that has lasted weeks to months, not responding to antibiotics
Haemoptysis
Spiking fever
Night sweats and weight loss

Question 4

What signs can be seen in TB?

Answer 4

Clubbing
Monoarthropathy
Erythema nodosum
Scrufuloderma

Question 5

What is a scrufuloderma?

Answer 5

Skin lesions from underlying TB in a lymph node, bone or joint

Question 6

What other diseases are included in the differential for TB?

Answer 6

Lung cancer
Sarcoidosis
Lymphoma

Question 7

What is the spectrum of disease caused by TB?

Answer 7

Pulmonary
Pleural
Extra-pulmonary
Meningeal
Miliary

Question 8

Which form of TB produced a very strong antimicrobial response?

Answer 8

Pleural

Question 9

What are common sites of extra-pulmonary TB?

Answer 9

Bone
Kidneys
Skin

Question 10

What investigations should be done into TB?

Answer 10

Sputum for ZN stain and culture or PCR for rapid diagnosis
CXR
Mantoux test

Question 11

What does a positive smear and culture of TB mean?

Answer 11

Very infective

Question 12

What does a negative smear but positive culture mean?

Answer 12

Latent TB

Question 13

What does a positive smear and negative culture mean?

Answer 13

Treatment is working as the bacteria are dead

Question 14

Why does TB often infect the upper lobes of the lung?

Answer 14

High V/Q ratio: brought in on high airflow and not cleared due to lower blood flow

Question 15

What does a 5mm Mantoux test mean?

Answer 15

Positive in HIV and recent contacts

Question 16

What does a 10mm Mantoux test mean?

Answer 16

Positive in moderate risk (travel, IVDU)

Question 17

What does a 15mm Mantoux test mean?

Answer 17

Positive in no known risk factor

Question 18

What is measured in the Mantoux test?

Answer 18

Elevation

Question 19

What causes a false positive Mantoux test?

Answer 19

Other mycobacterial infection

BCG vaccine

Question 20

What causes a false negative Mantoux test?

Answer 20

Anergy
Recent TB infection
Very young
Live-virus vaccine
Overwhelming TB

Question 21

What is the treatment for pulmonary TB?

Answer 21

Isoniazid, rifampicin, pyrazinamide and ethambutol for 2 months
Isoniazid and rifampicin for 4 months

Question 22

What is the treatment for neuro and miliary TB and why is it given?

Answer 22

Corticosteroids: dampen the immune response to dead TB

Question 23

How long is the course of antibiotics for extra-pulmonary TB?

Answer 23

9-12 months

Question 24

What are the side effects of isoniazid?

Answer 24

Hepatotoxicity

Peripheral neuropathy

Question 25

What is given to prevent peripheral neuropathy in isoniazid treatment?

Answer 25

Pyridoxine (vit B6)

Question 26

What are the side effects of rifampicin?

Answer 26

Hepatotoxicity | Turns secretions orange

Question 27

What are the side effects of ethambutol?

Answer 27

Optic neuritis

Question 28

What are the side effects of pyrazinamide?

Answer 28

Hepatotoxicity

Question 29

What TDM is done for a patient being treated for TB?

Answer 29

Monitor pre-treatment LFTs and 2 weeks after starting Drugs should be discontinued if transaminases are >5 times normal Drugs reintroduced individually and sequentially

Question 30

Define multi-drug resistant TB

Answer 30

Resistant to isoniazid and rifampicin

Question 31

Define extremely drug resistant TB

Answer 31

Resistant to isoniazid, rifampicin and 3+ classes of second line agents

Question 32

How is latent TB diagnosed?

Answer 32

Mantoux test | IGRA

Question 33

What is the treatment for latent TB?

Answer 33

1. isoniazid for 9/12 2. rifampicin for 4/12 3. rifapentine and isoniazid for 3/12

Question 34

What is the difficultly in treating someone with TB and HIV?

Answer 34

Interactions between HAART and anti-TB drugs

Question 35

What is the BCG vaccine effective in preventing?

Answer 35

Childhood miliary TB and TB meningitis