TB

Question 1

what is TB bact

Answer 1

mycobacterium

• special cell envelope
• leads to it being acid fast - doesn’t show up on gram stain
• grows slowly - slow cultures

Question 2

how is TB transmitted

Answer 2

ppl with pulmonary or laryngeal aerosolize

- local defences can destroy if it doesn’t get too deep

Question 3

what happens if gets into alveoli

Answer 3

• cell mediated immunity creates a granuloma

- person now has latent TB

Question 4

what is chance of going active

Answer 4

10% will go active
50% of those in 2 year
- most TB in world is reactivated

Question 5

what is TB in toronto

Answer 5

from immigrants

Question 6

2 ways to test latent

Answer 6

1. skin test - TST

2. interfereon gamma release assay - IGRAS

Question 7

3 ways to diagnose active

Answer 7

1. acid fast bacilli and cultures
2. path consisitent with necrotizing granulomas
3. clinical presentations

Question 8

what is TST

Answer 8

• glyscerol extract of TB is put in skin

- read 48-72 hours later

Question 9

what is IGRA

Answer 9

• tests to see if WBCs from infected patient will release IFN-g when mixed with antigens from TB

Question 10

how does TST and IGRA compare

Answer 10

• IGRA are more specific than TST if previus BCG given
• neither can separate latent from active
• IGRA more specific for TB versus other non TB bacterium

Question 11

3 parts of interpreting TST

Answer 11

1. size of induration
2. PPV
3. risk of disease if truly infected

Question 12

3 levels and situations that would be considered pos.

Answer 12

0-4

- normal, but for children

Question 13

2 things that PPV is confounded by on TST

Answer 13

1. previous BCG - after 1yo
2. previous NTM
   - found in soil and such stuff

Question 14

7 things that make a person high risk

Answer 14

1. AIDS
2. HIV
3. tranplant
4. silcosis
5. chronic renal failure
6. carcinoma of head
7. recent TB

Question 15

7 things that make increased risk

Answer 15

1. steroid tx
2. TNF-a is
3. diabetes
4. underweight
5. young when infected
6. smoker
7. granuloma

Question 16

what to do if find pos. TST

Answer 16

rule out active TB

• Hx and Phx
• CXR
• sputum

Question 17

4 groups to offer Tx to

Answer 17

1. ALL CONVERTERS
2. new immigreants
3. HIV and immunosupressed
4. those with increased risk

Question 18

what is LTB Tx

Answer 18

1. INH 9 mo

2. rifampin 4 mo

Question 19

what are SE of isoniazide

Answer 19

• hepatotoxicity
• rash
• GI upset
• peripheral neuropathy

Question 20

how to test after pot. TST

Answer 20

will always test pos. again, and can get bigger

Question 21

Sx of active TB

Answer 21

• cough
• fever, chills, night sweats
• weight loss
• hemoptysis

Question 22

4 other risk factors

Answer 22

• aborig
• previous TB or contact
• marginalized pop
• immunosupressed

Question 23

3 steps if active suspected

Answer 23

1. isolation precautions
2. CXR
3. resp secretion analysis

Question 24

what are extrapulm manifestations

Answer 24

• nodal
• pleural
• CNS
• percardial
• MSK
• peritoneal
• genitourinary
• miliary (disseminated)

Question 25

what is MGMT of active

Answer 25

always start 4 drugs until cultured 1. INH 2. rifampin 3. pyrazinamide 4. ethambutol

Question 26

why different drugs

Answer 26

hits different types

Question 27

3 different types

Answer 27

1. extracellular with high O2 2. areas of low O2: inside cells, areas of fibrosis or caseum 3. areas of fibrosis or solid caseum