Infection in the immunocompromised Host Flashcards
1
Q
What are innate defences?
A
- Skin (barrier, sebum, normal flora)-iv, urinary catheters, surgery & burns
- Interferons, complement, lysozyme, acute phase proteins
- Mucous membranes (tears, urine flow, phagocytes)
- Normal commensal flora in gut
2
Q
What are the classifications of immunodeficiencies
A
Congenital or primary
Acquired or secondary
3
Q
What are neutrophil defects?
A
- Chemotaxis-rare, congenital, inadequate signalling, abnormality in receptors/ NE movement
- Killing power-inherited, CGD, deficient in NADPH oxidase so hydrogen peroxide not formed
- Cancer treatment, bone marrow, malignancy, aplastic anaemia caused by drugs
- Neutropenic
4
Q
What are T cell deficiencies?
A
- Congenital=rare
- Acquired= drugs: cyclosporin after transplantation, steroids, viruses (HIV)
5
Q
What opportunistic pathogens cause T cell deficiencies?
A
_ May be intracellular
- Bacterial: listeria monocytogenes (food), mycobacteria
- Viral: Leukaemia & transplants, HSV, VZV, serological testing, prophylaxis & treatment with acyclovir & ganciclovir
- Fungal: candida, cryptococcus
6
Q
What protozoan & parasitic infections lead to T cell deficiencies? Describe them
A
- Cryptosporidium parvumasporozoa-oocysts shed by cattle/human
- Faecal-oral route, most patients recover after prolonged illness unto 3 weeks, takes longer in T cell deficient patients, Symptomatic treatment
- Toxoplasma gondii-cats, humans infected by contact with cats faeces, may present with lesion in brain & neurological signs
- Strongyloides stercoralis-nematode, larvae penetrate skin & migrate, immunocompromised get multiplication, huge tissue invasion, may get gram negative septicaemia as larvae move
7
Q
What is hypogammaglobulinaemias?
A
- antibody problems
- Congenital=rare
- Acquired= multiple myeloma, chronic lymphocytic leukaemia, burns
- Usually encapsulated bacteria- S.pneumoniae in respiratory tract
