14 - Infection in the immunocompromised Flashcards
Classification of immunodeficiencies
Congenital or primary
Acquired or secondary
Types of neutrophil defects
Qualitative - chemotaxis, rare, congenital, inadequate signalling
Qualitative - killing power, inherited, chronic granulomatous disease. Deficient in NADPH oxidase so hydrogen peroxide not formed.
Quantitive - cancer treatment, bone marrow malignancy, aplastic anaemia
T cell deficiency types
Congenital - rare
Acquired - drugs (ciclosporin after transplant & steroids); viruses e.g. HIV
Opportunistic pathogens - bacterial
Bacterial - listeria monocytogenes (food)
Opportunistic infections - viruses
Viral - leukaemia and transplanted patients, HSV, CMV, VZV, serological testing, prophylaxis and treatment e.g. clovir drugs
Opportunistic infections - fungal
Fungal - candida, cryptococcus
Opportunistic infections - protozoa & parasites
Protozoan¶sitic - cryptosporidium parvum - oocysts by cattle/humans. Faecal-oral route. Most patients recover after prolonged illness of up to 3 weeks. Takes longer in deficient patients.
Toxoplasma gondii - cats. Cat faeces. Transplanted heart.
Strongyloides stercoralis. Larvae penetrate skin and migrate. Comes with rash. Multiply, huge invasion of tissues. Gram –ve septicaemia as larvae move. Suspect in tropical countries.
What are hypogammaglobulinaemias
Antibody problems
Congenital - rare
Acquired - multiple myeloma, chronic lymphocytic leukaemia, burns
Usually encapsulated bacteria
Complement deficiency
Hereditary, rare
Encapsulated bacteria - need complement to help kill organisms.
Classical and alternative - neisseria meningitidis (C5-8) lysis not achieved via MAC
Function of spleen
Source of complement and Ab producing B-cells, removes opsonised bacteria from blood.
Why would someone remove a spleen?
Trauma, surgical or functional e.g. sickle cell anaemia
