Tuberculosis

Question 1

Is TB nationally notifiable?

Answer 1

Yes - urgent (within 1 day); labs, doctors

Question 2

Which organism causes TB?

Answer 2

Mycobacterium tuberculosis complex bacteria

Also M. bovis, africanum and others but rare in Aus

Question 3

How is TB transmitted?

Answer 3

Aerosols (pulmonary / laryngeal TB)

Extrapulmonary and latent TB non-transmissible.

Question 4

What are the clinical features of TB?

Answer 4

Latent: ASx
Active
* Pulmonary - fever, weight loss, cough, haemoptysis.
* Extrapulmonary - many sites e.g. cerebral, vertebral (Pott’s disease)

Question 5

What is the incubation period of TB?

Answer 5

2-10 weeks

Progression to active in 5-10%; takes weeks to decades

Question 6

What is the infectious period for TB?

Answer 6

As long as bacteria aerosolised
Pulmonary TB - up to 3/12 prior to Sx
Risk declines within days of Rx

Extrapulmonary and latent non-infectious.

Question 7

Which groups are at high-risk of TB infection?

Answer 7

• Close contacts of infectious cases
• Migrants, refugees
• Some FNs comunities
• HCWs worked overseas
• Immunosupressed
• HIV
• Smoking
• DM
• Children < 5, elderly
• Malnutrition

Question 8

What are the case definitions for TB?

Answer 8

Confirmed - clinical OR culture OR PCR

Question 9

How is TB diagnosed?

Answer 9

• Mantoux test
• CXR
• IGRA (QFN)
• Culture (AFB smear, 21days)
• PCR

Question 10

What proportion of the global population have latent TB?

Answer 10

~ 1/3rd

Question 11

Which regions have the highest TB burden?

Answer 11

Africa, SEA, WPR

Question 12

What proportion of latent TB progresses to active?

Answer 12

~10%

Question 13

What is the incidence of TB in Australia?

Answer 13

Low - 5-6 cases per 100,000 (not decreasing)

Question 14

What is the prevalence of LTBI in Australia?

Answer 14

~ 5%

Question 15

What is the prevalence of LTBI in overseas-born people?

Answer 15

~ 17%

Question 16

What is MDR and XDR TB?

Answer 16

Multi-drug resistant (2 drugs)
Extended drug resistant (>2 drugs)

MDR 2-4% of cases; XDR rare

Question 17

What resources are available for PH management of TB?

Answer 17

SoNG
DH protocol
Management of TB risk in HCW guideline

Question 18

How is TB prevented?

Answer 18

• Vaccination (BCG)
• Pre-migration health screening (medical exam/CXR)
• Education - for travellers; cough etiquette

Question 19

How effective is the TB vaccine?

Answer 19

Children
* 25% against TB infection
* 70% against active TB
* 80% against severe disease e.g meningitis

Adults - ranges from 0-80% (average ~50%)

Question 20

Why is the BCG vaccine not on the NIP?

Answer 20

TB incidence low in Australia

Question 21

How are cases of TB managed?

Answer 21

Comprehensive case management - patient-centred, multi-disciplinary:
* Treatment - 4+ ABx (RIPE) for 6 months; DOTS for non-compliance
* Isolate - acutely unwell: NP room, aerosol precautions
* Exclude - until deemed non-infectious; 2wks Rx, 3 x negative sputum
* Education - cough etiquette, importance of compliance

Question 22

How are contacts of TB managed?

Answer 22

Individual assessment (consider case infectiousness - clinical, radiological, lab)

Stratify by risk
Time-based stratification - high-risk - >= 8 hrs e.g. HH, school, work
Education - natural hx, sx, testing (latent), treatment (curable but compliance required)