Infection of the immunocompromised Flashcards
Common types of pathogens more prevalent during immunosuppression.
- Bacteria
- Viruses
- Fungi
- Parasites/Protozoa
what functions can be disrupted if you are immnocompromised.
•Disruption of specific defence of an organ/system.
– Can be humoral- B cell and antibodies
– Can be cellular- T cells.
innate defences
skin,
Interferons, complement, lysozyme, acute phase proteins
Mucous membrane e.g lungs
2 types of immunodeficiences
congenital or acquired
what is the second line of defence if the innate system is breached
neutrophils
what are the 2 types of neutrophil defects
qualitative- rare
quantitative-common
example of qualitative neutrophil defect
– Congenital,
– Inadequate signalling
– Abnormality in receptors or NE movement
example of quantitative neutrophil defect
- eg - cancer treatment, bone marrow malignancy, aplastic anaemia caused by drugs
- Neutrophil level 50% will dvlp an infection.
typical problems caused by lines
- Bacterial infections – Gram negative bacilli (e.g E. coli), Gram positive cocci (e.g. S. aureus ) - often normal flora which translocate from the blood to the gut. E.g. Coagulase negative staph
- Fungal infections – Candida spp. , Aspergillus spp.
Common T cell deficiencies
1 congenital
2 acquired
- Congenital – rare e.g T helper cell disfucntion.
- Acquired – drugs e.g. ciclosporin after transplantation (decreases graft versus host disease and rejection), steroids
- Acquired – viruses e.g. HIV
In T cells deficincnecy what types of opportunistic pathogenic organisms are present.
- BACTERIAL – Listeria monocytogenes (food- cheese) this is why it is not recommended in pregnant women, Mycobacteria – MTB, MAI
- VIRAL – e.g. leukaemia and transplanted pnts - HSV, CMV (pre–emptive treatment), VZV. Serological testing, prophylaxis and treatment with e.g. aciclovir and ganciclovir
- FUNGAL – e.g. Candida spp., Cryptococcus spp common in meningitis
In T cell deficiency what ypes of parasitic/protazoan infections occur.
- Cryptosporidium parvum
- Toxoplasma gondii
- Strongyloides stercoralis.
Is hypogammaglobulinaemia congenital or acquired
acquired- multiple myeloma, chronic lymphocytic leukaemia, burns
what is hypoagammaglobinulinaemia
antobody deficency.
what is the treatment for Hypogammaglobulinaemias
antibodies and immunoglobulins.
Is complement deficiency congenital or acquired
congenital
what infection frequently occurs in complement deficiency
S. pneumoniae infections
removal of which organ can cause complement deficiency
spleen
source of complement and antibody producing, secondary lypkh organ
What is process of organ transplantation and where can infections occur along this process.
- The initial disease (e.g. HBV, liver transplant)
- Surgery and hospital admission (e.g. ventilator acquired pneumonia, S. aureus wound infection)
- Organ receipt (e.g. Toxoplasmosis, CMV), patient matching
- Opportunistic infection during initial immunosuppression (initial 3/12, e.g. CMV, Aspergillus)
- Later opportunistic infection (after 3/12, e.g. Zoster, Listeria)
what is the main tests are used to investigate an infection
• Blood cultures. Occasionally bone marrow cultures.
respiratory samples
urine
histology (what is happening at a cellular level)
CT/imaging
What methods are used to prevent infections
- Hand washing /aseptic technique / protective isolation / HEPA air filtration (allografts)
- Vaccines (avoid live vaccines in T-cell deficient)- for the 3 encapsulated bacteria.
- Prophylactic antimicrobials (e.g. penicillin, septrin, aciclovir) and passive immunoglobulin
- Special diet
what types of infections affect you when you are immunocompromised
common
rare
