The Immunocompromised Host Flashcards Preview

[ ESA 3- Infection and Immunity > The Immunocompromised Host > Flashcards

Flashcards in The Immunocompromised Host Deck (109):
1

What is meant by immunocompromisation?

State in which the immune system is unable to respond appropriately and effectively in infectious microorganisms

2

What is immnocompromisation due to?

A defect in one or more components of the immune system

3

What can infections suggest?

An underlying immune deficiency

4

When can infections suggest an underlying immune deficiency?

If they meet the criteria of SPUR

5

What is in the SPUR criteria?

Severe
Persistent
Unusual
Recurrent

6

What is considered to be a severe infection?

Life threatening

7

What is considered to be a persistent infection?

Minimal response to standard treatment

8

What factors may be considered unusual in an infection?

Site
Type of microbe

9

What site might be considered unusual in an infection?

Deep tissue

10

What type of microbe may be considered unusual in an infection?

Opportunistic infection

11

What is meant by a recurrent infection?

Returns regularly after treatment

12

What are the types of immunodeficiency?

Primary
Secondary

13

What kind of conditions are primary immunodeficiencies?

Congenital

14

What are primary immune deficiencies due to?

Intrinsic cell defect

15

How many intrinsic cell defects are there causing primary immunodeficiencies?

~275 genes

16

What can intrinsic cell defects lead to in primary immune deficiencies?

Missing protein
Missing cell
Non-functional components

17

What kind of conditions are secondary immunodeficiencies?

Acquired

18

What are secondary immune deficiencies due to?

Underlying disease/treatment leading to ;
Decreased production/function of immune components
Increased loss or catabolism of immune components

19

Do primary immune deficiencies affect the innate or adaptive immune system?

Can be either

20

What conditions have a decreased production of immune components as a result of a secondary immune deficiency?

Malnutrition
Infection (HIV)
Liver diseases
Lymphoproliferative diseases
Splenectomy

21

What are the functions of the spleen?

Sensing blood borne pathogens
Producing antibodies
Removal of opsonized microbes and immune complexes

22

What blood borne pathogens does the spleen especially sense?

Encapsulated bacteria

23

What antibodies does the spleen produce?

IgM
IgG

24

When does the spleen produce IgM?

Acute response

25

When does the spleen produce IgG?

Long term response

26

How does the spleen remove opsonised microbes and immune complexes?

By splenic macrophages

27

How does someone with a splenectomy present?

Increased susceptibility to encapsulated bacteria
Overwhelming post-splenectomy infection

28

What bacteria are asplenic people susceptible to?

Haemophilus influenzae
Streptococcus pneumoiae
Neisseria meningitidis

29

What is the risk of death from post-splenectomy infection?

1-2% risk of death from overwhelming sepsis/meningitis over 15 years

30

How is a person with a splenectomy managed?

Lifelong penicillin prophylaxis
Immunisation against encapsulated bacteria
Medic alert bracelet

31

What can an increased susceptibility to infections in haematological malignancies be due to?

Chemotherapy induced neutropenia
Chemotherapy induced damage to mucosal surfaces
Vascular catheters penetrating innate immune barriers

32

How should a suspected neutropenia sepsis be treated?

As an acute medical emergency, with empiric antibiotics
Assess a patients risk of septic complications

33

What can an increased loss or catabolism of immune components be due to?

Protein losing conditions
Burns

34

Give two protein losing conditions

Nephropathy
Enteropathy

35

What gives the large spectrum of primary immune deficiencies (PIDs)?

Different clinical phenotypes

36

How many PIDs are there?

>300

37

What is needed regarding PIDs?

Better diagnostic criteria

38

Why is a better diagnostic criteria needed for PIDs?

General failure to recognise and diagnose PIDs

39

When are most PIDs diagnosed?

~8-12 years from onset of symptoms

40

What % of patients will be 18 years old + when diagnosis is made?

>60%

41

What % of patients will have permanent tissue/organ damage by the time a diagnosis is made?

37%

42

What can help recognise PIDs?

The 10 warning signs

43

What are the 10 warning signs of PID for children?

4 or more new ear infections within 1 year
2 or more serious sinus infections within 1 year
2 or more months on antibiotics with little effect
2 or more pneumonias within 1 year
Failure of an infant to gain weight or grow normally
Recurrent, deep skin or organ abscesses
Persistent thrush in mouth, or fungal infections on skin
Need for intravenous antibiotics to clear infections
Two or more deep-seated infections including septicaemia
A family history of PID

44

What are the 10 warning signs of PID for adults?

2 or more new ear infections in 1 year
2 or more new sinus infections within 1 year in the absence of allergy
One pneumonia per year for more than 1 year
Chronic diarrhoea with weight loss
Recurrent viral infections (colds, herpes, warts, and condyloma)
Recurrent need for intravenous antibiotics to clear infections
Recurrent, deep abscesses of the skin or internal organs
Persistent thrush or fungal infections on skin or elsewhere
Infection with normally harmless tuberculosis-like bacteria
A family history of PID

45

What are the limitations of the 10 warning signs?

Lack of population-based evidence that can aid diagnosis
PID patients have different defects/presentations
PID patients with non-infectious manifestations

46

What population based evidence is there regarding the warning signs for PID?

Study on children concluded that 96% of PIDs could be diagnosed with the '3 warning signs'

47

What are the 3 warning signs that a study says 96% of children with PID can be diagnosed based on?

Family history
Failure to thrive
Diagnosis of sepsis treated with IV antibiotics

48

What is the problem with the 3 warning signs when diagnosing PID?

It does not take into account PIDs in adults - the largest proportion of people with PID
Found not to be good at diagnosing antibody deficiencies

49

Give 4 examples of deficiencies leading to PIDs?

T cells
B cells
Phagocytes
Complement deficiencies

50

How can PID patients have different presentations?

Some infections have subtle presentations

51

What PID patients may have a noninfectious manifestation?

Autoimmunity
Malignancy
Inflammatory response

52

Does the distribution of malignancies among primary immunodeficiency disorder subgroups vary?

Yes

53

How can the types of PID be identified?

Age at symptom onset
Types of microbes
Sites of infection

54

What does a PID onset of <6 months highly suggest?

A T-cell or phagocyte defect

55

What does a PID onset of >6 months and <5 years often suggest?

A B-cell/antibody or phagocyte defect

56

What does a PID onset of > 5 years and later in life usually suggest?

A B-cell/antibody/complement or secondary immunodeficiency

57

What bacteria are associated with a complement deficiency PID?

Neisseria
Streptococci
Haemophilus influenzae
Other encapsulated bacteria

58

What bacteria are associated with phagocytic defect PIDs?

Staph. aureus
Pseudomonas aureginosa
Non-tuberculous mycobacteria

59

What fungi are associated with phagocytic defect PIDs?

Candida
Aspergillus

60

What bacteria are associated with antibody deficiency PIDs?

Streptococci
Staphylococci
Haemophilus influenzae
Moraxella catarrhalis
Pseudomonas aeruginosa
Mycoplasma pneumoniae

61

What viruses are associated with antibody deficiency PIDs?

Enteroviruses

62

What protozoa are associated with antibody deficiency PID?

Giardia lamblia

63

What bacteria are associated with T cell defect PIDs?

Similar to antibody deficiencies, but also include;
Salmonella
Listeria monocytogenes
Non-tuberclous mycobacteria

64

What viruses are associated with T cell defect PIDs?

All viruses

65

What fungi are associated with T cell defect PIDs?

Candida
Aspergillus
Cryptococcus neoformans
Histoplasma capsulatum

66

What protozoa are associated with T cell defect PIDs?

Pneumocystis
Toxoplasma gondii
Cryptosporidium parvum

67

What sites of infection are complement deficiencies associated with?

Pyogenic infections
Meningitis/sepsis/arthritis

68

What complement deficiency is associated with pyogenic infections?

C3

69

What complement deficiency is associated with meningitis/sepsis/arthritis?

C5-9

70

What sites of infection are associated with phagocyte defects?

Skin/mucous infections
Deep seated infections
Invasive fungal infections

71

What invasive fungal infection is associated with phagocyte defects?

Aspergillosis

72

What sites of infection are associated with antibody deficiencies?

Sino-respiratory infections
Arthopathies
GI infections
Malignancies
Autoimmunity

73

What will T cell defects lead to if not treated?

Failure to thrive and death

74

What sites of infection are associated with T cell defects?

Deep skin and tissue abscesses
Opportunistic infections

75

What are the classes of primary immunodeficiencies?

Predominantly antibody deficiencies
Combined T and B cell
Phagocytic defects
Other cellular immunodeficincies

76

What % of PIDs are predominantly antibody deficiencies?

65%

77

Give 5 predominantly antibody deficiency PIDs

Bruton's disease
Autosomal recessive agammaglobulinaemia
Common variable immunodeficiency (CVID)
Selective IgA deficiency
IgG subclass deficiency

78

What % of PIDs are combined T and B cells?

15%

79

Give 2 combined T and B cell deficiencies

SCID
Omenn syndrome

80

What % of PIDs are phagocytic defects?

10%

81

Give 3 phagocytic defects

Chronic granulomatous disease
Severe congenital neutropenia
Cyclic neutropenia

82

What % of PIDs are other cellular immunodeficiency

5-10%

83

Give 4 other cellular immunodeficiencies

Wiskott-Aldrich syndrome
DiGeorge syndrome
Hyper IgE syndrome
Ataxia-telangiectasia

84

Why is it important to consider the pattern of family history with PIDs?

To help identify any possible X-linked conditions

85

Give an example of an X-linked PID?

Bruton's disease

86

How will patients with CGD often present?

With pulmonary aspergilliosis and skin infections

87

How are PIDs managed?

Supportive treatment
Specific treatment
Avoid non-essential exposure to radiation
Assess organ damages

88

What are the supportive treatments for PID?

Infection prevention
Treat infection promptly and aggressively
Nutritional support
Use UV-irradicated CMVneg blood products only
Avoid live attenuated vaccines in patients with severe PIDs

89

How are infections prevented in PID?

Prophylactic antibiotics

90

What nutritional support is given in PID?

Vitamins A and D

91

What are the specific treatments for PID?

Regular immunoglobulin therapy
Avoid non-essential exposure to radiation
Assess organ damages

92

What is the aim of regular immunoglobulin therapy in PIDs?

Get serum IgG > 8g/l

93

How can immunoglobulin be administered?

IV or SC

94

What is regular immunoglobulin therapy used for?

CVID
XLA
Hyper-IgM syndrome

95

Does aspergillus cause disease?

Does not usually cause disease in immunocompetent, but major problem for immunocompromised

96

What is aspergillusosis?

An opportunistic fungal infection

97

Where can aspergillus be found?

In most buildings

98

What can aspergillus inhalation cause?

Can cause aspergillosis in the lungs

99

What happens to the varicella-zoster virus in immunocompetent individuals?

It is kept in the latent phase by T cell surveillance after chickenpox infection

100

When may the VSV virus be reactivated?

When there is an altered T-cell response or number in immunodeficient patients

101

What does the reactivation of the VSV virus cause?

Shingles

102

When does shingles usually appear in healthy patients?

Usually in aging patients (thought to be linked to reduced T cell responses)

103

What are the potential sites of infection of S. aureus?

Skin and soft tissue
Respiratory
Musculoskeletal
Cardio-vascular
Genitourinary tract
Diseases caused by toxins

104

What skin and soft tissue infections are caused by S. Aureus?

Furuncles, carbuncles
Wound infection (traumatic or surgical)
Cellulitis
Impetigo

105

What respiratory infections can be caused by S. Aureus?

Pneumonia

106

What musculoskeletal infections can be caused by S. Aureus?

Osteomyelitis
Arthritis

107

What cardiovascular infections can be caused by S. Aureus?

Endocarditis
Septicaemia

108

What genitourinary infections can be caused by S. Aureus?

Renal carbuncle
Lower urinary tract infections

109

What diseases can be caused by S. Aureus toxins?

Toxic shock syndrome
Scalded skin syndrome
Food poisioning