Tuberculosis

Question 1

What bacteria causes tuberculosis?

Answer 1

Mycobacterium tuberculosis

Question 2

Give two reasons why it is very difficult to culture M. tuberculosis:

Answer 2

1) they are very slow at dividing
2) they have high oxygen requirements

Question 3

What does acid-fast mean?

Answer 3

physical property of certain microorganisms with unique cell wall composition that makes them resistant to acid decolorization such that Gram staining is not effective

Question 4

What staining method is used for M. tuberculosis?

Answer 4

Ziehl Neelson

Question 5

How does M. tuberculosis appear on Ziehl Neelson staining?

Answer 5

bright red on a blue background

Question 6

How is tuberculosis transmitted?

Answer 6

Droplets

Question 7

What is primary active tuberculosis?

Answer 7

active infection following exposure

Question 8

What is latent tuberculosis?

Answer 8

Presence of M. tuberculosis without being symptomatic or infectious

Question 9

What is secondary tuberculosis?

Answer 9

reactivation of latent tuberculosis into an active infection

Question 10

What is miliary tuberculosis?

Answer 10

disseminated and severe disease where the immune system cannot control the infection

Question 11

What is the most common site of TB infection?

Answer 11

Lungs

Question 12

Give 8 potential extrapulmonary sites of TB infection:

Answer 12

1) lymph nodes
2) GI system
3) pleura
4) bones and joints
5) skin
6) pericardium
7) genitourinary system
8) CNS

Question 13

What does BCG vaccine stand for?

Answer 13

Bacille Calmette-Guerin

Question 14

What is the name of the tuberculosis vaccination?

Answer 14

BCG vaccine

Question 15

What does the BCG vaccine contain?

Answer 15

live attenuated Mycobacterium bovis, a close relative of M. tuberculosis

Question 16

True or false: the BCG is a routinely offered vaccine

Answer 16

false (it is only offered to high risk patients)

Question 17

Give 4 risk factors for TB infection:

Answer 17

1) close contact with active TB
2) immigration and travel from areas with high TB prevalence
3) immunocompromised
4) malnutrition, homelessness, smokers, alcoholics and drug users

Question 18

What test should be completed before every BCG vaccine?

Answer 18

Matnoux test (must be negative before giving the vaccine)

Question 19

Give 9 presentations associated with tuberculosis:

Answer 19

1) haemoptysis
2) cough
3) lethargy
4) fever or night sweats
5) weight loss
6) lymphadenopathy
7) spinal pain
8) erythema nodosum
9) cold abscesses (in the neck)

Question 20

Describe erythema nodosum:

Answer 20

tender, red nodules on the skins caused by inflammation of subcutaneous fat

Question 21

What are the two immune tests used to diagnose TB infection?

Answer 21

1) Mantoux test
2) Interferon gamma release assay

Question 22

What substance is injected into the skin during the Mantoux test?

Answer 22

tuberculin

Question 23

Describe a positive result of the Mantoux test:

Answer 23

after 72 hours, the bleb in the skin will from a thickened, indurated patch spanning 5mm or more

Question 23

What is tuberculin?

Answer 23

a collection of tuberculosis proteins

Question 24

Describe the interferon-gamma release assay:

Answer 24

mixing a blood sample with antigens from M. tuberculosis so that if the patient has been exposed to the bacteria before, WBCs will become sensitised and release interferon gamma

Question 25

Give 3 CXR findings in line with primary tuberculosis:

Answer 25

1) patchy consolidation
2) pleural effusion
3) hilar lymphadenopathy

Question 26

Give 2 CXR findings in line with reactivated tuberculosis:

Answer 26

1) patchy/ nodular consolidation
2) cavitation (gas filled spaces)

Question 27

What CXR finding supports a diagnosis of disseminated tuberculosis?

Answer 27

millet seed appearance spread uniformly across the lungs (small 1-3mm nodules)

Question 28

True or false: TB cultures can take several months

Answer 28

True

Question 29

How many sputum samples should be taken when investigating TB?

Answer 29

3

Question 30

What are the three types of culture that should be completed for TB investigation?

Answer 30

1) sputum cultures (x3)
2) Mycobacterium blood cultures (requires special blood culture bottle)
3) lymph node aspiration or biopsy

Question 31

What does NAATs stand for?

Answer 31

Nucleic acid amplification tests

Question 32

Describe how NAATs can be used to investigate TB:

Answer 32

a sputum can be taken and genetically analysed, providing info much faster than cultures

Question 33

Give 3 instances where NAAT would be used to investigate TB:

Answer 33

1) in those with HIV
2) in those under 16
3) where there are risk factors for multi drug resistance

Question 34

What two medications are used to treat latent TB?

Answer 34

1) isoniazid
2) rifampicin

Question 35

What 4 medications are used to treat active TB?

Answer 35

1) Rifampicin
2) Isoniazid
3) Pyrazinamide
4) Ethabutol

Question 36

What medication is prescribed alongside isoniazid?

Answer 36

Vitamin B6 (as isoniazid causes peripheral neuropathy)

Question 37

True or false: every TB case needs to be made known to the UK Health Security Agency

Answer 37

True

Question 38

Give 2 side effects of rifampicin:

Answer 38

1) makes secretions orange/ red (red-i’m-pissin)
2) induces cytochrome p450 enzymes meaning other drugs are metabolised rapidly and are thus less effective

Question 39

Give a side effect of isoniazid:

Answer 39

peripheral neuropathy (i’m-so-numb-azid)

Question 40

Give a side effect of pyrazinamide:

Answer 40

hyperuricaemia (gout and kidney stones)

Question 41

Give a side effect of ethambutol:

Answer 41

colour blindness and reduced visual acuity (eye-thambutol)