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ESA 3 - Respiratory System > Tuberculosis > Flashcards

Flashcards in Tuberculosis Deck (93):
1

What do mycobacteria possess? 

A lipid-rich cell wall 

2

What does the lipid-rich cell well of mycobacteria do? 

Retains some dyes, even resisting decolourisation with acid (acid-fast)

3

How is TB spread from person to person? 

By the aerosol route 

4

What is the first site of infection for TB? 

The lung 

5

What is the outcome of primary TB? 

Most infections resolve with local scarring 

6

What does TB post-primary infection refer to? 

The development of tuberculosis beyond the first few weeks 

7

What may happen in TB post-primary infection? 

The infection may progress throughout the body 

8

What is it called when TB spreads throughout the body? 

Miliary spread 

9

What is the outcome of miliary spread of TB? 

  • May resolve spontaneously 
  • May develop into localised infection 

 

10

Give an example of a localised infection that may result from miliary spread of TB

Meningitis 

11

What happens to Mycobacterium TB once inside the body? 

It is ingested by macrophages

12

What happens to Mycobacterium TB once it has been ingested by macrophages? 

It escapes from the phagolysosome to multiply in the cytoplasm 

13

What does the intense immune response to Mycobacterium TB cause? 

Local tissue destruction and cytokine-mediated systemic effects 

14

What does local tissue destruction as a result of TB infection cause? 

Cavitation in the lung 

15

What cytokine-mediated systemic effects are caused by infection with TB? 

Fever and weight loss 

16

What organs may TB affect? 

Any organ of the body 

17

What does TB mimic? 

Both inflammatory and malignant diseases 

18

How may pulmonary TB present? 

  • Chronic cough
  • Haemoptysis 
  • Fever
  • Weight loss
  • Recurrent bacterial pneumonia 

 

19

What happens if pulmonary TB is left untreated? 

It follows a chronic, deteriorating course 

20

How does tuberculous meningitis present? 

  • Fever
  • Slowly deteriorating level of consicousness 

 

21

How may a kidney infection present? 

  • Local infection 
  • Fever
  • Weight loss

 

22

What are the potential complications of a kidney infection? 

  • Ureteric fibrosis 
  • Hydronephropathy 

 

23

What is a common site of bone infection? 

The lumbosacral spine 

24

What may progression of a bone infection in the lumbosacral spine cause? 

  • Vertebral collapse 
  • Nerve compression

25

What may inflamamation of large joints lead to? 

Destructive arthritis 

26

What does Mycobacterium TB stimulate once it has escaped from macrophages? 

An immune response, with the release of IL-12 

27

What is the effect of IL-12? 

It drives the release of IFN-γ and TNF-α from NK and CD4 cells 

28

What is the effect of IFN-γ and TNF-α? 

They activate and recruit more macrophages to the site of infection, resulting in the formation of granulomas 

 

29

What are the primary changes in TB? 

  • Few symptoms 
  • Lymph nodes may become englarged in young people 

 

30

What is the classical presentation of post-primary TB? 

  • Cough (not always productive)
  • Fevers towards the end of the day, or at night 
  • Weight loss and general debility 

 

31

What does a chest x-ray show in a patient with post-primary TB? 

  • Pulmonary shadowing, which may be patchy with solid lesions
  • Cavitated solid lesions 
  • Streaky fibrosis 
  • Flecks of calcification 

 

32

What are the signs of respiratory TB? 

Non-specific 

  • Pallor 
  • Fever
  • Weight loss
  • Clubbing
  • Palpable lymph nodes 

 

33

What are the symptoms of respiratory TB? 

Primary usually asymptomatic

  • Tiredness and malaise 
  • Weight loss and anorexia 
  • Fever
  • Cough 
  • Breathlessness
  • Occasionally, haemoptysis 

 

34

What are the x-ray changes shown in respiratory TB? 

  • Shadowing
  • Cavities 
  • Consolidation 
  • Calcification
  • Cardiomegaly 
  • Miliary seeds 

 

35

Who is pleural TB more common in? 

Males 

36

What are the two mechanisms of pleural involvement in TB? 

  • Hypersensitivity response to primary infection
  • Tuberculous empyema with ruptured cavity 

 

37

What does tuberculous empyema have a tendancy to do? 

Burrow through the chest wall 

38

What is almost always present with pleural tuberculosis? 

Some pulmonary disease 

39

Who is lymph node TB more common in? 

  • Children 
  • Women 
  • Asians 

 

40

What is often true of lymph node TB? 

It is painless

41

Where does lymph node TB most commonly occur? 

In the neck

42

What happens in oesto-articular TB? 

TB burrows into bone 

43

Give two types of osteo-articular TB

  • Poncet's disease 
  • Tuberculous Spondylitis 

 

44

What is the most common form of oestoarticular TB? 

Tuberculous Spondylitis 

45

What is the passage of Tuberculous Spondylitis? 

  • Starts in sub-chondral bone 
  • Spreads to vertebral bodies and joint space
  • Follows longitudinal ligaments, anterior and posterior to spine

 

46

Where does Tuberculous Spondylitis mainly occur? 

In the lower thoracic and lumbar spine, but can be very high

47

What is it called when Tuberculous Spondylitis occurs very high? 

Cervical tuberculosis 

48

What may result from Tuberculous Spondylitis? 

Parapledia and quadriplegia 

49

In what % of Tuberculous Spondylitis cases does parapledia and quadripledia result? 

25%

50

What is Poncet's Disease? 

Aseptic polyarthritis 

51

Where does Poncet's disease affect? 

Knees, ankles, and elbows 

52

What happens in miliary TB? 

Bacilli spread through the blood stream

53

When does miliary TB occur? 

Either during primary infection or as reactivation 

54

When are the lungs involved in miliary TB? 

Always 

55

How is mililary TB spread throughout the lungs? 

Evenly 

56

Why is miliary TB spread throughout both lungs? 

It is in the blood 

57

How can miliary TB in the lungs be visualised? 

Many visibile on an x-ray 

58

What do headaches suggest in miliary TB? 

Meningeal involvement 

59

What are the clinical features of miliary TB? 

  • Ascites may be present 
  • Retinal involvement in children 
  • Few respiratory symptoms 

 

60

How is TB diagnosed? 

  • Clinical features 
  • Radiological features 
  • Microbiology 

 

61

What clinical features aid in the diagnosis of TB? 

  • Cough
  • Night fever
  • Weight loss

 

62

What radiological features aid in the diagnosis of TB?

  • Shadowing
  • Cavities 
  • Consolidation
  • Cardiomegaly 
  • Miliary seeds 

 

63

What microbiological features aid in the diagnosis of TB? 

  • Indentification of bacillus 
  • Direct smear and subsequent culture of the appropriate body fluid

 

64

What is important when considering the microbiology of TB? 

To isolate organism and determine its susceptibility to drugs 

65

How is TB treated? 

Initially, patients are treated with four drugs for two months, after which two of them are dropped and the others continued for another four months 

66

What drugs are used in the initial phase of treatment of TB? 

  • Rifampicin 
  • Isoniazid
  • Pyrazinamide
  • Ethambutol 

 

67

What drugs are used in the continuation phase of treatment of TB? 

  • Rifampicin 
  • Isoniazid

 

68

Why are multiple drugs used in the treatment of TB? 

In an attempt to combat resistance 

69

What % of TB patients are resistant to isoniazid?

5-10%

70

Why does TB treatment have problems with compliance? 

It is quite a long regime, with several different pills to take 

71

How is compliance with TB treatment improved in the US? 

15% of patients receive Directly Observed Therapy (DOT)

72

What are the benefits of Directly Observed Therapy? 

Improved cure rate, reduction in rate, drug resistance, and relapses 

73

What are the potential reactions to rifampicin? 

  • Hepatitis 
  • Rash
  • Flu-like symptoms 
  • Shock
  • ARF
  • Thrombocytopenic purpura 

 

74

What are the potenital reactions to isoniazid? 

  • Rash 
  • Peripheral neuropathy
  • Hepatitis 

 

75

What are the potential reactions to pyrazinamide? 

  • Rash
  • Hepatitis 
  • Arthralgia 

 

76

What are the potential reactions to ethambutol? 

Optic neuritis 

77

What is happening to the incidence of multidrug-resistant TB? 

There is a rising trend 

78

How many TB bacilli are spontaneously resistant? 

About 1 in a million 

79

What is a case of multidrug-resistant TB (MDRTB) suggested by? 

  • A history of previous incomplete treatment
  • Residence in a country with high incidence of MDRTB
  • Failure to response clinically to an adequate regimen 

 

80

What is used to attempt to combat TB resistance? 

A regimen of several drugs at once 

81

What is the BCG vaccine? 

A vaccination against TB that is prepared from a strain of the Attenuated Liver Bovine Tuberculosis Bacillus 

82

What must be true for the TB bacteria to act as a vaccine for human TB? 

They must retain a strong enough antigenicity 

83

What are the problems with the BCG vaccine? 

  • The vaccine has variable efficacy
  • Efficacy only lasts 15 years at most

 

84

What does the efficacy of the BCG vaccine depend on? 

Genetic variation of populations and BCG strains 

85

What are the UK regulations regarding the BCG vaccine? 

Up until 2005, all children ages 13 were immunised along with all neonates born into high-risk groups. 

Post 2005, the vaccination was only given to high-risk groups 

86

Why was the BCG vaccine only given to high-risk groups post 2005? 

Falling incidence of TB had reduced the vaccine's cost effectiveness 

87

What groups are at high risk of TB? 

  • HIV
  • Silicosis 
  • Malnutrition 
  • Overcrowding
  • IV drug abusers 
  • Chronic lung disease 
  • Asians 
  • Diabetes 
  • Corticosteroid users 
  • Anti α-TNF antibody (infliximab) users

 

88

Where may overcrowding be a problem? 

  • Prisons
  • Homeless shelters 

 

89

Who is at risk of developing chronic lung disease? 

Smokers 

90

By how much does the risk of developing TB increase in HIV infected people compared to uninfected people? 

Estimated to be 20-37 times greater

91

What is the problem with TB in HIV patients? 

Its a leading cause of morbity and mortality 

92

What happens if a patient has suspected TB? 

Contact is immediately made with TB radiology. The patient goes straight into a TB clinic, with no waiting times, and is given a questionnaire and sputum samples taken

93

How long after TB is suspected does treatment begin? 

Within 7 days