L70 – Tuberculosis: a re-emerging public menace Flashcards Preview

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Flashcards in L70 – Tuberculosis: a re-emerging public menace Deck (66):
1

What is the estimated human population infected with MTB?

Estimated 2-3 billion people (~1/3 human population) has been infected with
Mycobacterium tuberculosis

2

How does TB rank as a cause of death?

5th leading cause

3

What is the disease ratio of TB (ratio of new infection to
development of overt disease) ?

Recall Tb has primary (dormant, host immune not activated) and post-primary infections:

5% > primary infection within 5 years

Further 5% > post-primary disease

4

What is the main diagnosis for TB?

Clinical

other include rapid molecular tests, sputum smear, culture, sensitivity testing ...etc

5

What are the methods to estimate TB incidence?

Registration system

National notification/ prevalence survey

Surveillance system

6

What does the huge difference between estimated incidence and number of TB notifications mean?

That many TB patients have not been diagnosed/ treated in healthcare systems

7

How does estimate TB mortality rate differ in HIV patients?

HIV = more susceptible to TB

8

What is the trend of TB mortality in HIV-ve and +ve patients?

Both decline:

HIV -ve declines at a much higher rate than HIV +ve

9

What is the decline in TB mortality rate between 2000 and 2015?

34%

10

What is the target for TB incidence rate decline by 2020

4-5%

11

Which global regions have the fastest and slowest decline in TB mortality?

Fastest = Eastern mediterranean and Europe

Slowest = Africa

12

What is the difference between the countries at the top of Incidence: absolute numbers chart and Incidence: Rate chart?

Incidence: absolute numbers chart >> occupied by developing/ developed countries with huge populations (e.g. China, India) but situation is IMPROVING

Incidence: Rate chart>> occupied by undeveloped countries where situation is NOT IMPROVING

13

The top 6 countries with the largest number of incident cases account for __ % of global total ?

60

14

What are some predisposing factors to TB?

Age (adult predominant)
Sex (male predominant)
HIV, diabetes
Prior mycobacterial infection
Immunocompromise host


Confounded by socio-economic and environmental conditions

15

What are the stats on TB propagation in a community? (how many people can infection pass onto...)

Each infection on average produces ≥ 1 secondary infection

Each untreated infects 20-28 persons

6-10% develop active disease

16

How many cases of infectious TB is considered an endemic?

1 case

17

How does the supply of susceptible individuals compare to the rate of being infected by TB?

Supply of susceptible ≥ Rate of being infected

Supply can be from birth, immigration..etc to increase population size

18

What is the reproductive ratio (r0)?

Estimation of the rate of infection spread

19

Given TB declined before medication or vaccines, what causes the most impact in reducing TB incidence?

Improve hygiene and public health

20

What are the 5 risk factors of POVERTY that affects rate of community acquired TB?

E H PSP
Ed Has a PSP

Economic
Human
Political
Socio-cultural
Protective

21

How does poverty lead to increased risk of getting TB?

Poverty itself cannot cause TB,

but poor living conditions in many complex interacting pathways could affect the risk of getting TB

22

What are the 3 components of living condition?

-Community (e.g. housing density, planning, access, pollution...)

-Household (e.g. crowded, ventilation, security...)

-Individual (e.g. economic status, smkoing, cancer, abus...)

23

How many TB cases are due to smoking?

20% attributable to TB

24

How many times greater is the risk of TB given HIV=ve?

20-30x greater than HIV
negative persons

25

Why doe TB have atypical presentation in HIV patients?

Late presentation

Poorer outcomes (HIV progresses very fast)

Less infectious (smear negative) but still transmissible

26

What does HRZES refer to in TB drugs?
Presi > Zresh

isoniazid (H), rifampicin (R), pyrazinamide (Z), ethambutol (E), streptomycin (S)

27

What are the combos for First line TB drugs?

 2HRZE(S) [2 months]; or
 4HR [4 months]


* isoniazid (H), rifampicin (R), pyrazinamide (Z), ethambutol (E), streptomycin (S)

28

What is XDR-TB resistant to?

At least H, R + an injectiable drug + a fluoroquinolone

29

2nd line TB drugs?

FEC

Fluoroquinolone
Ethionamide
Cycloserine

30

Which cases of TB should be treated with second line MDR-TB treatment?

Rifampcin resistant TB and MDR-TB

31

What are the main causes of drug-resistance TB?

Unregulated OTC drug sale

Poor supervision of therapy

Wrong prescription

32

What are some supply/ production issues of TB drugs that lead to resistance

Intermittent drug supplies
Combo preparation is poorly done or unavailable
Usage of expired drugs

33

What is the DOTS stratgey and when is it used?

Directly observed therapy, short course

>> core component of End TB Strategy for controlling TB

34

What is the purpose of DOTS? (think funding and drugs)

Ensure uninterrupted access to high quality anti-TB drugs and adequate money for complete course of antibiotics

35

What are the new MDR/RR-TB drugs ?

Bedaquiline
Delamanid

36

Why is treatment of MDR/RR-TB not that successful?

Shortage of trained staff

Limited market > all options very expensive

Not enough number of facilities for treatment and monitoring

37

What is the Vision and Goal of the End TB strategy?

Vision: zero deaths and suffering due to TB

Goal: End the Global TB epidemic

38

3 pillars of End TB Startegy?

1. Integrated, patient-centred
care and prevention

2. Bold policies and supportive systems

3. Intensified research and innovation

39

2 criteria for the TB high-burden country list?

Top 20 in terms of absolute number of TB cases

Meet threshold of incidence rate per capita

40

Compare rate of incidence of TB in hong kong vs western countries?

Western = less than 10/100,000

HK = 58/100,000

41

Give 3 reasons for the drop in TB notification rate in HK over the last 40 years?

1) Ageing population **
2) Improved surveillance and reporting
3) Long latency of reactivation > increasing proportion of TB cases

42

Why did rate of TB drop during WWII when the conditions should increase incidence?

Breakdown of infrasturcture for surveillance and reporting = under-report rates

43

Compare the age groups affected by Progressive primary infection and non-primary infections of TB?

Primary = younger

Non-primary = reactivation = older

44

What age group most affected by MDR and MDR-TB?

40-49 most

age group = middle aged

45

Is TB notification compulsory in HK?

Yes, Notified by law, send to Department of Health

46

What is the use of notification of TB?

Initiation of contract tracing

Provide info about epidemiology of TB

47

What are centers for TB services?

Directly approach DoH CHEST CLINIC

or

Referral from private practice, GOPD

48

Number of TB Chest clinics? Managed by?

17 HK TB and Chest Service centers

Managed by DoH

49

What are the 3 ways DoH chest clinics improve service to help treat TB?

- Free treatment

- Ant-TB meds and treatment are given under FULL supervision (avoid incomplete course of meds...etc)

- Extended opening time > accessibility

50

What is the lab supporting DoH chest clinics?

TB Reference Lab of DoH

51

Give the reasons for HA to admit a TB patient for inpatient, given most TB cases are outpatient?

- Social reasons/ problems with adherence (e.g. retarded)

Management of:
- disease complication
- treatment complication
- other medical conditions
- Investigations (e.g. bronchoscopy)

52

What are the most important stretgies for controlling TB in HK?

- Case finding
- Effective chemotherapy
- Treat latent TB infection
- BCG vaccine

(+ health education)

53

What are the low and high cost effectiveness screening strategies for TB?

Low: Mass CXR (no longer done in HA)

High: Screening contacts/ contact-tracing

54

What is the approach of contact tracing?

' concentric circle apporach' > people in very close contact examined first

55

Difference in the screen tests done for active TB and latent TB infection?

Active = CXR, clinical symptoms, sputum microscopy

Latent: Tuberculin skin test (Purified Protein Derivative...etc )

56

Is CXR effective for screening TB in HIV patients?

No, low yield

57

What processes follow smear +ve and smear +ve results from TB contact investigations?

Smear +ve = start clinical treatment immediately

Smear -ve = CXR (sometimes +Tuberculin skin test)

58

What is passive case finding?

Walk-in, self-reported cases with symptomatic patients

Cost effective, accounts for over 90% TB cases in HK

59

What is important to achieving effective chemotherapy?

Effective regimes are prescribed

High Patient adherence to treatment and duration

60

Why is ineffective chemotherapy TB worse than no therapy?

Increase resistance of TB
Increased risk of repeated relapses

>> chronic infections

61

2 benefits to improve diagnosis and treatment of latent TB infection?

Reduce pool of infected in populaiton

Rapid control over disease

62

What are some problems of treatment of Latent TB infections?

Imperfect diagnostic tools (e.g. hard to interpret positive tuberculin skin test given high BCG coverage)

Difficult to achieve patient adherence (hard to motivate, commit)

Prologned course have side effects

63

What are the high risk groups in latent TB infections?

Infants with close contact with smear +ve patients

Similar aged contacts under 35 (with at least 15m tuberculin response/ conversion from -ve to +ve result)

Tuberculin +ve, HIV-infected or silicosis

64

Which age group is protected by BCG?

Children

BCG is given to all newborn and children under 15 without vaccination

65

Why is health education important to combat TB?

Raise awareness
Reduce stigma
Promote passive case finding
Improve patient adherence to treatment

>> not to set rules, but to reach mutual understanding/ partnership

66

Are all TB patients adherent or not to anti-TB treatments?

All TB patients are NATURALYY NON-ADHERENT to Anti-TB meds

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