Pulmonary mycobacterial diseases Flashcards Preview

Year 2 Respiratory > Pulmonary mycobacterial diseases > Flashcards

Flashcards in Pulmonary mycobacterial diseases Deck (35)
1

how are atypical or non TB mycobacteria infections classified?

rapid or slow growing mycobacteria

2

what are the rapid growing mycobacteria?

M. fortuitum complex
M. chelonae
M. absessus

3

what are the slow growing mycobacteria?

M. kansasii
M. marinum
MAC (avium, intracellulare)

4

progressive lung disease in non-TB pulmonary infections typically occurs in what type of patient?

underlying bronchiestasis or COPD

5

what are the two clinical forms of MAC? what are the demographics?

fibrocavitary - older male smokers with preexisting lung disease

fibronodular - nonsmoking women over 50 without underlying lung disease

6

what is the clinical presentation of non-TB mycobacterial infections?

usually typical or TB with cavitation 85-95%

7

what is required for diagnosis of non-TB mycobacteria?

bacteriologic confirmation

sputum (2 positive cultures)
BAL sample
lung or tissue biopsy positive AFB smears
positive culture from pleural effusion fluid

8

what are the three possible consequences of TB contraction?

1. immediately cleared - no infection
2. primary TB - immediate onset of active disease
3. latent infection - possibility of reactivation

9

what % of the dormant population will develop a reactivation of TB infection?

5%

10

what % of individuals who contract TB eventually devleop infection?

30%

11

how does TB spread upon infection?

lymphatics - to regional lymph nodes

12

what is a Ghon complex on CXR?

unilateral lymphadenopathy suggestive of TB

13

what occurs if cell mediated immunity is inadequate? what is the result?

hematogenous dissemination - active disease and contagiousness

14

pulmonary symptoms occur in what % of cases of primary TB?

33% (1/3)

15

what are the radiographic findings of primary TB?

normal CXR
hilar adenopathy
perihilar infiltrates
effusion

16

what type of TB infection is most common?

latent

17

how is latent TB diagnosed?

evidence of cell mediated immune response to initial infection manifested by:

positive TB skin test (PPD Mantoux)
interferon gamma release assay (Quantiferon Gold)

18

how is the tuberculin skin test administered?

intradermal injection of 0.1 mL of purified protein derivative (PPD)

19

how are PPD tests analyzed?

mm induration of skin

NOT erythema perpendicular to long axis

20

what does a positive TB skin test mean?

documents infection but NOT active disease

21

what is associated with active TB infection / disease?

clinical and radiographic findings or disease

22

when does a skin test become positive? what does it document?

several weeks after infection

document a cellular immune response

23

what test is approved for screening for latent TB?

interferon gamma release assay

24

what is involved in the interferon gamma release assay?

T cell release of IFy following exposure to antigen specific to M. tuberculosis

25

can the interferon gamma release assay determine if infection is active or latent?

no

26

can the PPD skin test determine if infection is active or latent?

no

27

which TB test is NOT affected by BCG vaccination?

IFy release assay

28

what is the therapy for latent TB infection?

isoniazid 300 mg daily for 9 months

29

what drug is used for TB resistant to isoniazid?

rifampin

30

what are the features of the fever associated with TB?

more marked as disease progresses and is classically diurnal

31

what are the general principles of TB therapy?

1. always use at least two drugs that have documented activity against the strain of TB
2. always use appropriate drug doses
3. the drug must be taken regularly
4. duration of therapy must be long enough for the circumstances

32

the initial phase of TB treatment requires how many drugs? for how long?

4 drugs
8 weeks

33

what is recommended for schedules that do not require daily doses?

DOT

34

the continuous phase of TB treatment requires how many drugs? for how long?

INH and RIF
additional 4-7 months

35

what indicates mycobacterium TB infection diagnostically?

positive sputum culture