Immunodeficiencies & infections Flashcards
Most Primary Immunodeficiencies are single gene defects, what are the 3 domains?
1) Ab deficiency due to defect in B cells
2) Cellular due to T cell defect
3) Innate due to PRRs, phagocytes or complement defect
What about a child’s illness would make you suspect an immunodeficiency?
SPURR:
- Severe
- Persistant
- Unusual
- Recurrent
- Runs in family
What infections arise from Ab deficiencies?
Recurrent resp bacterial infections incl Pneumococcus & H influenzae
What type of infections arise from T cell deficiencies?
Opportunistic infections incl Pneumocytic Jiroveccii pneumonia (PCP) & CMV pneumonia
What type of infections would you expect to see in a phagocyte defect?
Staph aureus –> Sepsis, skin inf & deep organ abscesses
Aspergillus –> Lung, bones & brain inf
What infections do you see in complement deficiency?
N. Meningitidis (So meningitis)
What could you do if you suspect Primary Immunodeficiencies?
Ab? –> Ab tests & measuring immune response to vaccination with common pathogens
T cell? –> Diff WCC & immunophenotyping
Complement? –> Measure complement activation & individual factors
What’s the main secondary immunodeficiency?
HIV/AIDS
How would you spot HIV/aIDS?
Recurrent/disseminated VZV/HSV
Opportunistic Inf e.g. CMV pneumonia or PCP
Recurrent RTIs & Persistant oral thrush
Erythematous popular rash, generalized lymphadenopathy & FTT/developmental delay
Invasive fungal infections e.g. Candida Albicans or Aspergillus Fumigatus are often a presenting symptoms of Primary immunodeficiency. What else would cause one?
- Neutropenia e.g. leukaemia/chemo
- Neonates (immature immunity)
- Broadspec Abx and/or abdo surgery
And primary immunodeficiency
What are the differences between an invasive candida vs aspergillus infection?
Candida:
- Endogenous
- Get from birth canal/staff’s hands
- +ve blood cultures
- Metastatic Foci
Aspergillus:
- Exogenous
- Get form air/water/environment
- -ve cultures with pulm disease
- Angio-invasive
Who tends to get neonatal Candidaemia?
Low BW babies( mainly prems) in their 2nd/3rd wk
What do you suspect in a premature neonate with sepsis syndrome, thrombocytopenia & Hyperglycaemia?
Neonatal Candidemia
Clue is the hyperglycaemia, in a bacterial infection that would be low