Tubercolosis

Question 1

Why do mycobacteria need to be stained with acid fast stain

Answer 1

Thick waxy cell wall prevents other stains being effective

Question 2

What is the main TB causing mycobacterium

Answer 2

M. Tuberculosis

Question 3

Do all mycobacteria cause TB

Answer 3

No

Question 4

How many mycobacteria species cause TB

Answer 4

5

Question 5

TB risk factors

Answer 5

Non UK born/ recent migrants from S Asia or sub Saharan Africa
HIV
Immunocompromised
Homeless
Drug use
Prisoners
Close contacts of TB
young adults
Elderly

Question 6

What airborne particles transmit TB person to person

Answer 6

Droplet nuclei

Question 7

How is TB spread

Answer 7

Inhaling droplet nuclei
Fomites

Question 8

What actions/behaviours increase TB spread

Answer 8

Cough
Sneezing
Speaking
Singing

Question 9

What affects the probability TB will be transmitted

Answer 9

Infectious mess of person with active TB
Environment exposure occurred
Exposure length
Virulence of tubercle bacilli
Host immunity
Host Co morbidities

Question 10

How can TB transmission be prevented

Answer 10

Isolate infected people
Quick Effective treatment

Question 11

Which area of the lungs do inhaled TB bacteria usually settle in

Answer 11

Sub pleural area of mid or lower lung zones

Question 12

What happens to inhaled TB bacteria once settled in the lung

Answer 12

Engulfed by alveolar macrophages -> Ghon focus formed -> TB laden macrophages travel to local lymph nodes -> Ghon complex formed -> active primary disease or initial containment

Question 13

Ghon focus

Answer 13

Primary lesion caused by mycobacterium bacilli

Question 14

What are the 3 possible outcomes of inhaling TB bacteria

Answer 14

Progress to primary active disease
Heals or effectively contained and stays latent
Initially contained then reactivates later - post primary TB

Question 15

What is post primary TB

Answer 15

Initially contained latent infection reactivated

Question 16

How does the immune system react differently to post primary TB than primary TB

Answer 16

Memory cells allow faster response, but immune system can overreact causing complications

Question 17

What % of people infected with Tb will never develop active disease

Answer 17

90

Question 18

TB infection

Answer 18

Presence of MTB in body - active or latent
Does not mean the person has TB disease

Question 19

TB active disease

Answer 19

Symptomatic Infection

Question 20

MTB latent infection

Answer 20

Living dormant MTB in body with no symptoms

Question 21

What is the biggest risk factor for latent TB reactivating

Answer 21

HIV

Question 22

How can latent TB be prevented from reactivating

Answer 22

Diagnosis
Chemoprophylaxis

Question 23

TB reactivation risk factors

Answer 23

HIV infection
Substance abuse
Prolonged corticosteroid therapy
Immunosuppressive therapy
Tumour necrosis factor alpha antagonists
Organ transplant
Haematological malignancy
Severe kidney disease / haemodialysis
Diabetes mellitus
Silicosis
Low body weight

Question 24

What condition is tested for in all suspected and confirmed TB cases

Answer 24

HIV

Question 25

What are the 3 types of TB

Answer 25

Pulmonary Tb Extra pulmonary TB Miliary TB

Question 26

Where does pulmonary TB occur

Answer 26

Lungs

Question 27

Where can extrapulmonary TB occur

Answer 27

Larynx Lymph nodes Pleura Brain Kidneys + adrenals Bones Joints

Question 28

Which groups is extrapulmonary TB more common in

Answer 28

HIV infected Immunosuppressed Young children

Question 29

Where does miliary TB occur

Answer 29

Bloodstream - carried to all parts of body

Question 30

What is the rarest type of TB

Answer 30

Miliary

Question 31

Features of characteristic TB lesion/ tubercle

Answer 31

Spherical granuloma with central caseation

Question 32

What type of reaction is caused by MBT ingested by macrophages in primary TB

Answer 32

Granulomatous reaction

Question 33

What cells surround the caseous necrotic core of a primary TB tubercle/lesion

Answer 33

Epithelioid macrophages Langhans multi uncleared giant cells Lymphocytes

Question 34

What makes up the caseous necrosis in the centre of a primary TB tubercle

Answer 34

Calcified cellular debris, dead MTB, and dead macrophages

Question 35

What type of lesions are caused by primary TB

Answer 35

Spherical granuloma

Question 36

What type of lesion is caused by post primary TB

Answer 36

Cavitary lesions

Question 37

Why do post primary TB cavitary lesions usually form in upper lung lobes

Answer 37

Better oxygenation aids aerobic MTB

Question 38

Are MTB aerobic or anaerobic organisms

Answer 38

Aerobic

Question 39

Pulmonary TB symptoms

Answer 39

Fever Night sweats Weight loss + anorexia Tiredness Malaise >3 wks cough Haemoptysis Dyspnoea

Question 40

What is the most common pulmonary TB symptom

Answer 40

Cough lasting 3+ wks

Question 41

Pulmonary TB signs

Answer 41

Pyrexia Crackles in affected areas Hyperesonnance Decr lung expansion Signs of pleural effusion

Question 42

How does pulmonary TB cause hyper resonance

Answer 42

Cavitation in severe disease

Question 43

How does pulmonary TB decrease lung expansion

Answer 43

Fibrosis in severe disease

Question 44

Which investigations are used to diagnose active pulmonary TB

Answer 44

Chest x ray Microbiology - sputum / induced sputum broncho alveolar lavage fluid samples Histology

Question 45

How does TB appear on CXR

Answer 45

Defined patchy consolidation Cavitation Fibrosis Pleural effusion

Question 46

Disadvantages of TB microscopy

Answer 46

Can’t differentiate MTB from non tubercolosal mycobacteria infection Can’t differentiate live and dead bacteria May be negative even in active disease

Question 47

Why might microscopy for a patient with active TB still come up negative

Answer 47

Early disease Specimen collection technique Poor cough reflex HIV AIDS

Question 48

What is the gold standard for TB diagnosis

Answer 48

Culture

Question 49

What test must be done before a suspected TB case can be declared negative

Answer 49

Culture must come back negative

Question 50

Why are both solid and liquid media used in a Tb culture

Answer 50

Liquid faster Solid more sensitive

Question 51

Which test can be used to detect multi drug resistant and extrpensively drug resistant TB in smear samples

Answer 51

Nucleus acid amplification tests

Question 52

What group receives the BCG vaccine

Answer 52

Babies in high prevalence communities New entrants from high risk areas Health care workers Close contact ps of active respiratory TB

Question 53

How does protection from BCG vaccine change over time

Answer 53

Decrease over time Little evidence for protection in adults

Question 54

How is latent pulmonary TB diagnosed

Answer 54

Tuberculin sensitivity test Interferon gamma assays

Question 55

What does the tuberculin sensitivity test measure

Answer 55

Cell mediated immune response

Question 56

How is the tuberculin sensitivity test carried out

Answer 56

Tuberculin injected Intradermally and induration measured 48-72 hrs later

Question 57

How is tuberculin injected in tuberculin sensitivity test

Answer 57

Intradermally

Question 58

Can the tuberculin sensitivity test and interferon gamma assays distinguish between latent and active MTB infection

Answer 58

No

Question 59

What does an interferon gamma essay measure

Answer 59

Interferon gamma - Cell mediated immune responses of T cells to MTB antigens

Question 60

Are sputum smears and cultures positive or negative in a person w latent TB

Answer 60

Negative

Question 61

Is latent Tb infectious

Answer 61

No

Question 62

Latent TB first line treatment

Answer 62

Isoniazid + pyridoxine/ vit B6 Isoniazid + pyridoxine + rifampicin

Question 63

Why should active Tb not be treated with a single drug

Answer 63

Increase drug resistance

Question 64

How many drugs are used in standard active TB treatment

Answer 64

4

Question 65

First line active TB drugs

Answer 65

Rifampicin Isoniazid Pyrazinamide Ethambutol RIPE

Question 66

Second line active TB drugs

Answer 66

Quinolones Injectable capreomycin, kanamycin, amikacin Ethionamide/prothionamide Cycloserine PAS linezolid Clofazamine

Question 67

Rifampicin side effects

Answer 67

Incr transaminases - liver enzyme Affects other drugs inc oral contraceptive Orange secretions

Question 68

Isoniazid side effects

Answer 68

Peripheral neuropathy - pyridoxine/b6 prevents Hepatotoxicity

Question 69

Pyrazinamide side effects

Answer 69

Hepatotoxicity

Question 70

Ethambutol side effects

Answer 70

Visual disturbance

Question 71

Why is pyridoxine given with isoniazid

Answer 71

Prevents peripheral neuropathy from isoniazid

Question 72

How long is TB treatment if no drug resistant suspected

Answer 72

6 months

Question 73

How is TB treatment adherence ensured

Answer 73

Directly observed theraoy Video observed therapy

Question 74

Why is TB treatment adherence supervised

Answer 74

Prevent transmission Lots of pills and side effects makes non adherence likely

Question 75

Multi drug resistant TB

Answer 75

Resistant to rifampicin and isoniazid

Question 76

Extremely drug resistant TB

Answer 76

Resistant to rifampicin, isoniazid, fluroquinolones, + 1+ injectable

Question 77

Why does Miliary tb affect multiple organs

Answer 77

Bacilli spread through blood

Question 78

How can extrapulmonary TB reach the gut

Answer 78

Swallowing tubercles in coughed up mucous

Question 79

Where does extra pulmonary TB occur in Potts disease

Answer 79

Spine

Question 80

Types of extrapulmonary Tb

Answer 80

Lymphadenitis Gastrointestinal Genitourinary Bone + joint Tuberculous meningitis

Question 81

When should TB be notified

Answer 81

Any suspected or made diagnosis

Question 82

Which group is BCG vaccine not effective in

Answer 82

HIV

Question 83

Why should people with HIV not receive the BCG vaccine

Answer 83

Not effective with HIV prevents future use of tuberculin sensitivity test

Question 84

What could cause a positive tuberculin sensitivity test in a person without TB infection

Answer 84

Preciously received BCG vaccine