The Immunocompromised Host Flashcards
1
Q
What is meant by immunocompromisation?
A
State in which the immune system is unable to respond appropriately and effectively in infectious microorganisms
2
Q
What is immnocompromisation due to?
A
A defect in one or more components of the immune system
3
Q
What can infections suggest?
A
An underlying immune deficiency
4
Q
When can infections suggest an underlying immune deficiency?
A
If they meet the criteria of SPUR
5
Q
What is in the SPUR criteria?
A
Severe
Persistent
Unusual
Recurrent
6
Q
What is considered to be a severe infection?
A
Life threatening
7
Q
What is considered to be a persistent infection?
A
Minimal response to standard treatment
8
Q
What factors may be considered unusual in an infection?
A
Site
Type of microbe
9
Q
What site might be considered unusual in an infection?
A
Deep tissue
10
Q
What type of microbe may be considered unusual in an infection?
A
Opportunistic infection
11
Q
What is meant by a recurrent infection?
A
Returns regularly after treatment
12
Q
What are the types of immunodeficiency?
A
Primary
Secondary
13
Q
What kind of conditions are primary immunodeficiencies?
A
Congenital
14
Q
What are primary immune deficiencies due to?
A
Intrinsic cell defect
15
Q
How many intrinsic cell defects are there causing primary immunodeficiencies?
A
~275 genes
16
Q
What can intrinsic cell defects lead to in primary immune deficiencies?
A
Missing protein
Missing cell
Non-functional components
17
Q
What kind of conditions are secondary immunodeficiencies?
A
Acquired
18
Q
What are secondary immune deficiencies due to?
A
Underlying disease/treatment leading to ;
Decreased production/function of immune components
Increased loss or catabolism of immune components
19
Q
Do primary immune deficiencies affect the innate or adaptive immune system?
A
Can be either
20
Q
What conditions have a decreased production of immune components as a result of a secondary immune deficiency?
A
Malnutrition Infection (HIV) Liver diseases Lymphoproliferative diseases Splenectomy
21
Q
What are the functions of the spleen?
A
Sensing blood borne pathogens
Producing antibodies
Removal of opsonized microbes and immune complexes
22
Q
What blood borne pathogens does the spleen especially sense?
A
Encapsulated bacteria
23
Q
What antibodies does the spleen produce?
A
IgM
IgG
24
Q
When does the spleen produce IgM?
A
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
