Mycobacterial disease : TB

Question 1

name 2 mycobacterium in; Mycobacterium Tuberculosis Complex

Answer 1

○ Mycobacterium tuberculosis

○ Mycobacterium bovis (BCG)

Question 2

how are non-tuberculous mb different from tuberculous ones?

Answer 2

also known as environmental mycobacteria

do not cause tuberculosis or leprosy

Question 3

M. abseccuss is a mycobacterium that has which growth speed?

Answer 3

fast

Question 4

why can’t TB be gram stained?

Answer 4

large amounts of lipid substances within their cell walls called mycolic acids.

These acids resist staining by ordinary methods such as a Gram stain.

Question 5

2 ways to detect tb in sample?

caveats?

Answer 5

Auramine - greater false positives

Zhiel-Neelson stain - less sensitive

Question 6

auramine and ZN stain are examples of which tests?

Answer 6

acid alcohol test

Question 7

Non-tuberculous mycobacteria are found where?

Answer 7

water and soil

Question 8

route of transmission of NTM?

Answer 8

NO person to person

rare animal to people

Question 9

who are high risk of NTM?

Answer 9

Immunocompromised:
HIV
transplant
Malignancy

lung disease - i.e. a1 antritypsin
post menopausal + Underlying lung disease

Question 10

which NTM causes:

Skin lesions e.g. Bairnsdale ulcer, Buruli ulcer
Chronic progressive painless ulcer

Answer 10

M. ulcerans

Question 11

which NTM causes:

Swimming pool granuloma

what is this?

Answer 11

M. Marinum

remember Marine

localized nodular skin inflammation (small reddish raised areas of skin)

Question 12

how does mycobacterium avium present in

a. immunocompetent
b. immunosuppressed

Answer 12

immunocompetent;
lung disease ; pre-existing cavities or bronchiectasis

immunosuppressed:
disseminated disease

Question 13

list 3 examples of slow growing tb

Answer 13

M Tuberculosis
M Bovis

M Avium

Question 14

M. abscessus, M. chelonae, M. fortuitum are rapid growing NTM.

they are usually found where?

Answer 14

Tattoos

In hospital settings;
Vascular catheters & other devices

Question 15

name the 3 microbiological diagnostic criteria for TB?

Answer 15

Positive culture >1 sputum samples

OR +ve BAL - bronchoaveolar lavage
OR +ve biopsy with granulomata

Question 16

Name some risk factors for NTM?

Answer 16

○ Age

○ Underlying lung disease

Question 17

how to treat rapid growing NTM?

Answer 17

Based on susceptibility testing, usually macrolide-based

Question 18

name 2 forms of Mycobacterium leprae?

difference?

Answer 18

○ Paucibacillary tuberculoid
§ Few skin lesions
§ Robust T cell response

○ Multibacillary lepromatous
§ Abundance of bacilli
§ Multiple lesions - v. deforming
§ Poor T cell response

Question 19

which is the 2nd most common cause of death by infectious agent ?

which is first?

Answer 19

1st - HIV

2nd - TB

Question 20

TB is the Most common opportunistic infection in which disease?

Answer 20

HIV

Question 21

3 possibilities post contact with TB infected person?

Answer 21

After contact with a person with TB, you could become
infected,

become latently infected or

not become infected at all

Question 22

which is 2nd most common Mycobacterial infection after MTB?

Answer 22

After m tb, m bovis most common infection in humans, others are rare

Question 23

MTB complex consists of how many closely related species?

Answer 23

7

Question 24

what is the Infectious dose of mtb?

Answer 24

1-10 bacilli

Question 25

who receives bcg vaccine? why?

Answer 25

babies protects from severe infection - but protection wanes little use in adults

Question 26

3 Stages of TB?

Answer 26

Primary Latent Reactivation

Question 27

Describe presentation of primary TB?

Answer 27

``` Usually asymptomatic Ghon focus/complex - granuloma Limited by CMI - cell mediated immunity Rare allergic reactions include Erythema nodosum Occasionally disseminated/miliary ```

Question 28

post-primary tb occur in which 2 forms?

Answer 28

reactivation reinfection

Question 29

Risk factors for reactivation of tb?

Answer 29

Immunosuppression Chronic alcohol excess Malnutrition Ageing

Question 30

which will have a better immune response; localised pulmonary tb OR lymph node tb?

Answer 30

LN TB

Question 31

how does Bone TB present?

Answer 31

Potts disease: - affects spine - caseous necrosis leads to disc damage and collapse causing spinal damage: Kyphosis possible paraplegia

Question 32

most affected nodes in LN tb?

Answer 32

cervial nodes; scrofula - leaks pus aka Lymphadenitis

Question 33

presentation of TB?

Answer 33

``` ○ Fever ○ Weight loss - "wasting disease" ○ Night sweats ○ Pulmonary (cough, haemoptysis) ○ Malaise Anorexia ```

Question 34

gold standrad in tb diagnosis?

Answer 34

culture takes weeks to return - slow growing

Question 35

ivx for latent tb?

Answer 35

Tuberculin skin test | IGRAs : interferon gamma release tests

Question 36

how many sputum samples needed in tb?

Answer 36

3

Question 37

maximum sensitivity of sputum samples for tb?

Answer 37

72%

Question 38

Role of NAAT for primary mtb samples?

Answer 38

Rapid diagnosis of smear +ve | Drug resistance mutations

Question 39

what does a tuberculin skin test tell you?

Answer 39

Previous exposure to Mycobacteria

Question 40

what should you look out for on histology of tb?

Answer 40

caseating granuloma

Question 41

what does induration size tell you in tuberculin test?

Answer 41

The reaction is read by measuring the diameter of induration . a low-risk patient must have a larger induration for a positive result than a high-risk patient. example: no risk factors: induration >15mm HIV + : induration >5mm

Question 42

issues with IGRAs?

Answer 42

Cannot distinguish latent & active TB

Question 43

treatment for NTM?

Answer 43

RA/CE instead of RIPE Rifampicin Azithromycin/Clarithromycin Ethambutol

Question 44

what is used (2nd line med) in isoniazid resistance?

Answer 44

Moxifloxacin

Question 45

side effects of Rifampicin?

Answer 45

Hepatotoxicity - raised transaminases Induces cytochrome P450 - interaction with COCPs and anti-epileptics Orange secretions - tell patients to watch out for this

Question 46

side effects of Isoniazid?

Answer 46

Peripheral neuropathy !! Hepatotoxicity SLE Psychosis

Question 47

Why monitor LFTs closely in patient treated for TB?

Answer 47

RIP - causes hepatotoxicity

Question 48

Side effects of Pyrizinamide?

Answer 48

P for Painful joints - gout Hepatotoxicity

Question 49

Side effects of Ethambutol?

Answer 49

E for Eyes: Optic neuritis - Visual disturbance

Question 50

List FULL wholistic treatment components for tb

Answer 50

Multidrug therapy Vitamin D - important in host defence Nutrition Surgery

Question 51

how does one take RIPE

Answer 51

Normal TB RIPE for 2, RI for 4 CNS TB RIPE for 2, RI for 8 (10 months total)

Question 52

which type of tb is resistant to fluoroquinolones (moxifloxacin) & at least 1 injectable

Answer 52

Extremely drug-resistant TB (XDR)

Question 53

how does Multidrug resistant TB present?

Answer 53

Resistance to rifampicin & isoniazid both equally common

Question 54

reasons for multi drug resistant tb?

Answer 54

Previous TB Rx HIV+ Known contact of MDR TB Failure to respond to conventional Rx

Question 55

what is the WHO recommendation on MDR TB treatment?

Answer 55

Use 7 drugs | for 9-12 months

Question 56

challenges of a tb and hiv co-infection?

Answer 56

Clinical history Less likely to be classical often absent in low CD4 count More likely extrapulmonary disease Smear CMS less sensitive

Question 57

what is the drug regimen for MDR TB?

Answer 57

QAPCE ○ Quinolones + aminoglycosides + para-aminosalicylic acid (PAS) + cycloserine + ethionamide 4/5 drug regimen with a longer duration qap- key

Question 58

also check out GUM/HIV placement notes

Answer 58

black notebook v useful

Question 59

name 3 slow growing NTM?

Answer 59

M. avium complex or avium Intracellulare M. marinum M. ulcerans

Question 60

name 3 fast growing NTM?

Answer 60

M. abscessus, M. chelonae, M. fortuitum

Question 61

name the first and second most common cause of death by infectious agent

Answer 61

1. HIV | 2. TB

Question 62

What percentage if world has tb

Answer 62

1/3rd

Question 63

how do we prevent peripheral neuropathy iwith isoniazid rx?

Answer 63

vitamin b6 - Pyridoxine

Question 64

out of RIP, which causes the most serious cases of hepatotoxicity?

Answer 64

isoniazid