TB

Question 1

population infected with TB

Answer 1

1/3 of the population

rate of new TB cases falling globally

Question 2

TB description

Answer 2

chronic, granulomatous disease caused by the bacterium mycobacterium tuberculosis

Question 3

TB caused by

Answer 3

Mycobacterium tuberculosis

Question 4

mycobacterium tuberculosis

Answer 4

phagocytksed by macrophages an dis found in membrane bound particles known as phagosomes

Question 5

infected phagosomes

Answer 5

does not mature to fuse with lysososomes/acidity

Question 6

granuloma formation

Answer 6

body contains intracellular mycobacterium tuberculosis within macrophages

Question 7

transmission of TB

Answer 7

aerosol transmission occurs from persons with infectious active TB disease
spread by droplet nulclei

Question 8

droplets of TB

Answer 8

remain suspended for long periods

expelled when a person with infectious TB coughs, sneezes, speaks or sings

Question 9

after environmental exposure

Answer 9

70% uninfected

30% infected

Question 10

after infected with TB

Answer 10

5-10% primary tuberculosis

90-95% latent TB infection

Question 11

after latent infection established

Answer 11

containment and persistence

a portion will develop reactivation disease

Question 12

risk factors for developing reactivation disease

Answer 12

10% healthy adults
20% children <5 years
30% HIV+ patients
40% children <2 years

Question 13

ghon complex

Answer 13

peripheral lesion and casiating lymph nodes
majority will heal lesion and remain asymptomatic, some will develop latent infection, some will develop progressive primary tuberculosis

Question 14

reactivation of latent TB

Answer 14

secondary tuberculosis

Question 15

secondary tuberculosis

Answer 15

localised caveating destructive lesions or progressive secondary TB

Question 16

miliary Tb

Answer 16

massive haematogenous dissemination from progressive primary or secondary TB

Question 17

TB & HIV

Answer 17

deadly synergy

- HIV infection promotes progression of TB infection to active disease

Question 18

risk for developing TB for HIV negative

Answer 18

10% lifetime risk

Question 19

risk for developing TB for HIV positive

Answer 19

10% annual risk

leading cause of death in those with HIV infection

Question 20

preventing TB in HIV positive cases

Answer 20

preventative therapy - isoniazid or combination isoniazid with rifampicin

Question 21

TB and poverty

Answer 21

increased risk of exposure
increased risk of disease after infection
less chance of being. diagnosed and of receiving effective treatment

Question 22

clinical manifestations of TB

Answer 22

• lungs
• pleura
• CNS
• lymphatic system
• genitourinary system
• bones and joints
• disseminated

Question 23

pulmonary TB symptoms

Answer 23

pulmonary TB

• productive prolonged cough
• chest pain
• haemoptysis

Question 24

systemic TB symptoms

Answer 24

• fever, chills, night sweats, loss of appetite, weight loss, fatigue

Question 25

TB diagnosis

Answer 25

- medical history and physical examination - chest x ray - tuberculin skin test or IGRA - sputum sweat microscopy - bacteriological culture - molecular diagnosis

Question 26

chest x-ray

Answer 26

early abnormalities are hard to see upper lobe cavities HIV infected patients and children less commonly have cavities

Question 27

tuberculin skin testing

Answer 27

intradermal infection of PPD (purified protein from TB) into forearm - measure diameter of induration (swelling) 48-72 hours later

Question 28

tuberculin skin test is positive if

Answer 28

>5mm in HIV infected | >10mm in HIV-free

Question 29

problems with tuberculin skin test

Answer 29

false positives - BCG, environmental mycobacteria | false negatives - immune suppression, advanced TB

Question 30

interferon gamma release assays

Answer 30

an in vitro version of the skin test Quantiferon stimulate whole blood from patients with TB antigensand measure release of IFN

Question 31

benefit of interferon gamma release assay

Answer 31

more specific/convenient | but costly

Question 32

sputum smear microscopy

Answer 32

sputum is concentrated, smeared on a slide, stained and an acid fast stain and viewed under a microscope cheap and does not require sophisticated laboratories low sensitivity

Question 33

mycobacterial culture

Answer 33

culture from sputum or other samples takes a long time and requires sophisticated labs biosafety risk to staff

Question 34

molecular diagnsosis

Answer 34

minultaneously detects presence of TB and resistance to rifampicin more sensitive than smear microscopy

Question 35

urine LAM

Answer 35

lipoarabinomannan TB found in urine of patients best in patients with HIV insensitive test

Question 36

BCG vaccination

Answer 36

can be given pre and post exposure live attenuated version of Mycobacterium Bovis reduces incidence and severity in children inconsistent results for adults

Question 37

INH preventive treatment

Answer 37

prevent from progressive from latent to active TB

Question 38

TB treatment

Answer 38

need to treat with multiple drugs - to prevent emergence of reistant strains minimum treatment duration is 6 months fro drug sensitive TB - slow growing bacertium which develops tolerance to drugs - not all bacteria are killed by drug exposure

Question 39

multidrug resistant is resistant to

Answer 39

isoniazid and rifampicin

Question 40

extensively drug resistant TB

Answer 40

resistance to injectable drugs

Question 41

TB infection prevention control

Answer 41

cohort or isolate patients