The immunocompromised host (not fin) Flashcards
What is CVID?
Common variable immune deficiency
How is CVID treated?
Intravenous immunoglobulin (IVIG)
What is an ‘immunocompromised’ host?
State in which the immune system is unable to respond appropriately and effectively to infectious microorganisms
(defect in one or more components of the immune system)
What are the two types of an ‘immunocompromised’ state (causes)?
1) Primary immunodeficiency
2) Secondary immunodeficiency
What is primary immunodeficiency?
Congenital immunodeficiency
-intrinsic gene defect = missing protein = missing cell = non-functional component
What is secondary immunodeficiency?
Acquired immunodeficiency
- Underlying disease/treatment (e.g. HIV, immunosuppressants)
- Decrease production/function of immune components
- Increased loss or catabolism of immune components
How can an infection be defined? SPUR
Severe
Persistent
Unusual
Recurrent
List some of the 10 warning signs to recognise and diagnose primary immunodeficiency
- Two or more ear infections within a year (4 for children)
- Two or more sinus infections within 1 year in absence of allergy
- Chronic diarrhoea with weight loss
- Recurrent viral infections
- Persistent thrush or fungal infection
(above are for adults, similar to children)
What are the limitations of the 10 warning signs for PID?
- General use = lack of population-base evidence
- PID patients with different defects/presentations = subtle, different components e.g. T cells, B cells etc.
- PID patients with non-infectious manifestations = autoimmunity, malignancy, inflammatory responses
What percentage of all PIDs is caused by antibody defect?
~65%
What problems are there in PID antibody defect?
- Defect in B cell development (X-linked agammaglobulinaemia = Bruton’s disease*)
- Defect in antibody production (common variable immunodeficiency, selective IgA deficiency, IgG subclass deficiency)
What percentage of all PIDs is caused by T cell defect?
~15%
What problems are there in PID caused by T cell defect?
- Combined B and T cell defect (B cells first affected)
- T cell defect (e.g. Di George syndrome (thymus))
What percentage of all PIDs is caused by phagocytic defects?
~10%
What problems are there in PID caused by phagocytic defects?
- Defects in respiratory burst (chronic granulomatous disease)
- Defect in fusion of lysosome/phagosome
- Defects in neutrophil production and chemotaxis
Age of symptom onset for T cell or phagocyte defect?
< 6 months
Age of symptom onset for a B cell antibody or phagocyte defect?
6 months to 5 years
Age of symptom onset for a B cell/ antibody/ complement or secondary immunodeficiency?
5 years +
What is SCID?
Severe combined immunodeficiency (B cells and T cells)
How does a chronic granulomatous disease usually present?
- Pulmonary aspergillosis
- Halo signs in HRCT scan
- Skin infections
What are supportive treatments for PID?
- Infection prevention (prophylactic antimicrobials)
- Treat infections promptly
- Nutritional support (e.g. vitamins)
- Use UV-irradiated CMVneg blood products only
- Avoid line attenuated vaccines
