Tuberculosis

Question 1

what atypical bacterias cause TB?

Answer 1

M.kansasii
M.chelonae
M.A.I; mycobacterium avium intercellulare group

Question 2

what bacteria are part of the M.T.B group?

Answer 2

M.tuberculosis
M.bovis
BCG
M.africanum

Question 3

what is the vague structure of TB mycobacteria?

Answer 3

they have a thick cell wall and mycolic acid

Question 4

mycobacterium is acid fast, what stains can be used?

Answer 4

1. ziehl-neelsen

2. auramine

Question 5

how does the ziehl neelsen stain work?

Answer 5

Its added, heated and then stains the organism red

Question 6

how does the auramine stain show TB?

Answer 6

it fluoresces and is used more in practice

Question 7

how do you culture mycobacteria in a solid medium?

Answer 7

In a Lowenstein Jensen medium

slow process at 3-6 weeks and need a lot of bacteria in the sample

Question 8

what is mycobacteria culture moving towards a liquid medium?

Answer 8

It’s much faster so can be done in days instead of weeks

Question 9

what are the advantages of using PCR for TB?

Answer 9

rapid
specific
resistance information

Question 10

what is the disadvantage of using PCR for TB?

Answer 10

not as sensitive as culture

Question 11

what populations are at risk of TB?

Answer 11

immigrants
elderly
immunosuppressed; HIV, Lymphoma, long term steroids or chemo
diabetic
alcoholic
homeless

Question 12

what is the transmission of TB?

Answer 12

Droplet
direct contamination
infectivity related to sputum smear positivity.

Question 13

what is the time cut off for contact tracing?

Answer 13

spending 8 hours with the patient

Question 14

what is the course of primary infection of TB?

Answer 14

• the nuclei is inhaled into the mid lung zone
• the nuclei is ingested by alveolar macrophages
• the infected macrophages spread to the lymphatics

Question 15

what can primary infection progress to?

Answer 15

pneumonia, spread, meningitis, rupture into pleural space

Question 16

why can TB progress to active infection?

Answer 16

Stress, poor health, malnutrition, malignancy, immunosupresion, surgery

Question 17

what is seen histologically in pulmonary TB?

Answer 17

caeseous necrosis, granulomas, fibrosis, cavities in lung apex

Question 18

what is the clinical presentation of TB?

Answer 18

history of cough, weight loss, fever.

Question 19

what is tuberculous meningitis?

Answer 19

extrapulmonary TB of the CNS

rupture of the tubercle into sub arachnoid space.

Question 20

what is a common example of skeletal TB?

Answer 20

spine Potts disease

Question 21

what is the RIPE treatment for TB?

Answer 21

R rifampicin
I isoniazid
P pyrazinamide
E ethambutol

Question 22

Other than RIPE what are some other first line medications that can be given?

Answer 22

streptomycin

fluoroquinolone

Question 23

what are 2nd line treatments for TB?

Answer 23

ethionamide
Cycloserine
Capreomycin

Question 24

what are third line treatments for TB?

Answer 24

clarithromycin

Co-amoxiclav

Question 25

what is the RIPE regime?

Answer 25

RIPE given for initial 2 months rifampicin and isoniazid given for a further four months

Question 26

what is the RIPE regime for CNS TB?

Answer 26

RIPE for initial 2 months | rifampicin, isoniazid and steroids for a further 10 months

Question 27

what are some adverse reactions of rifampicin?

Answer 27

hepatitis rash GI upset drug interaction with prednisolone

Question 28

what are some adverse reactions of isoniazid?

Answer 28

rash peripheral neuropathy hepatitis

Question 29

what are some adverse effects of ethambutol?

Answer 29

dose related optic neuropathy

Question 30

what are some adverse effects of pyrazinamide?

Answer 30

``` hepatitis facial flush rash nausea high uric acid ```

Question 31

what are the expectations of treatment?

Answer 31

non infectious within 2 weeks | 1 month will gain weight and have a negative sputum smear

Question 32

if it's MDR TB what does this mean?

Answer 32

its resistant to isoniazid and rifampicin

Question 33

if it's XDR TB what does this mean?

Answer 33

resistant to isoniazid and rifampicin plus any fluroquinolone and at least one of the three infectable second line drugs (amikacin, kanamycin, capreomycin)

Question 34

what type of test is the tuberculin skin test?

Answer 34

A delayed type IV hypersensitivity reaction

Question 35

how long does the tuberculin skin test take?

Answer 35

- 12 hours you get interdigitating dendritic cells - 24-48 hours large numbers of activated macrophages in 48 hours; primed T cells

Question 36

what does the skin test measure?

Answer 36

the induration and erythema

Question 37

what does the blood test measure?

Answer 37

IFN gamma production

Question 38

explain the administration of the mantoux test?

Answer 38

0.1ml of 2TU staten serum institute PPD intra-dermally | wait 48-72 hours after it had been administered

Question 39

how do you interpret a mantoux test?

Answer 39

<5mm is negative | >15mm is likely to be TB

Question 40

what is interferon gamma release assay?

Answer 40

a new test for diagnosing TB in a test tube. lymphocytes are primed if there has been previous TB exposure so the interferon will be released faster, measuring the time period for gamma interferon to be produced

Question 41

what is special about the mycobacterium cell wall?

Answer 41

Coated in a thick mycolic acid layer causing higher resistance

Question 42

what is the gram staining on mycobacteria?

Answer 42

Due to the mycolic acid cell membrane it resists gamma staining

Question 43

how do you explain the granuloma you see in pulmonary TB?

Answer 43

a centre of macrophages which are infected (these will become necrosed), ssurrounded by lymphocytes. surrounded by T cells

Question 44

what is the caseous necrosis seen in pulmonary TB?

Answer 44

in the centre of the previous granuloma. it's previous bacteria and macrophages.

Question 45

in TB what is the ghon complex?

Answer 45

a calcified granuloma seen after primary TB.

Question 46

where is secondary TB found?

Answer 46

upper lobes

Question 47

what can be seen in a TB chest Xray?

Answer 47

Ghon complex calcification nodules