Week 10 Immunocompromised Flashcards
what are immunodeficiencies associated with and what is the risk of failing to recognise these?
- associated with increase in frequency and severity of infections
- associated with autoimmune diseases and malignancies
failure to recognise and diagnose leads to increased morbidity and mortality
- 37% of pts with an immunodeficiency will have permanent tissue/organ damage
how quickly are symptoms diagnosed, and at what age does this usually occur?
7-9yrs between onset of symptoms and diagnosis
50% of pts will be 18yrs old and older when diagnosis made
What is an immunocompromised host?
State in which immune system is unable to respond appropriately and effectively to infectious micro-organisms
Qualitative- 1 single element- HIV and
quantitative defect of one or more components of the immune system
Recognition and diagnosis of IDs- what suggest an ID?
Infection suggesting underlying immune deficiency defined as SPUR
S- severe
p- persistent- treatment not working
U- Site of infection- deep- cellulitis; unusual microorganism- opportunistic that wouldn’t cause disease in well
R- recurrent/resistant - keep coming back even with treatment
How are IDs classified and what is the difference?
primary and secondary
Primary- intrinsic defect- single gene disorder, polygenic, HLA polymorphisms
Secondary- more likely to encounter- underlying disease or condition affecting immune components- either- Decreased production (HIV), or increased loss or catabolism of components (liver disease)
How are primary IDs classified, and describe who is commonly affected and the incidence?
Classified according to which immune component is defective B cell- antibody deficiency (50%) T cell (30%) Phagocytes (18%) Complement (2%)
- 80% of pts will be
describe some different clinically important B cell deficiencies (antibody)
- common variable immunodeficiency (CVID)- Most common type that needs treatment- inability of B cells to mature into plasma cells, IgG low, IgA and IgM variable
- IgA deficiency- Most common incidence- B cell unable to switch to IgA- IgA undetectable
- IgG subclass deficiency
- Brutons disease (x linked agammaglobulinaemia XLA)-impaired B cell development- single gene defect- low IgG, IgA undetectable, low B cell
- Hyper- IgM syndrome- Cannot switch from IgM to IgG- IgG low
How do pts with primary antibody deficiencies present?
- Recurrent upper and lower resp infections- bacterial- bronchiectasis
- GI complications including infections (gardia)
- Increased incidence of Autoimmune disease- eg thrombocytopenia
- Increased incidence of lymphoma and gastric carcinoma
How are patients with primary antibody deficiencies managed?
- Prompt prophylactic ABs
- Immunoglobulin replacement therapy
- Management of resp functions- due to hyper secretion of mucus
- Avoid unnecessary exposure to radiation
what is immunoglobin replacement therapy (IRT)?
goal- serum IgG>8g/l- life long treatment
different formulations- IV/SC
conditions- CVID, XLA (brutons disease), Hyper IgM syndrome
What are some clinically important phagocyte deficiencies?
- Cyclic neutropenia- periodically- comes back every 6 weeks
- Leukocyte adhesion deficiency( LAD) - defect adhesion to epithelia due to lack of CD18 protein on phagocyte- increased number of neutrophils in blood
- Chronic granulomatous Disease (CGD)- defect in Intracellular killing- cannot generate oxygen dependant respiratory burst
- Chediak- Higashi syndrome- defect in phagocytosis- failure to form phagolysosome- microbe cannot be killed and will escape
Secondary phagocyte deficiency far more common
How do patients with phagocyte deficiencies present?
Prolonged and recurrent infections
- Skin and mucous membrane- ulcers
- Osteomyelitis, sepsis
- Deep abscesses
- Commonly spahylococcal (catalase +ve)
- Invasive aspergillosis
- inflammatory problems (granuloma)
How do you manage pts with phagocyte deficiencies?
- Prophylactic ABs/ anti fungal agents/ immunisation
- Surgical management - abscesses
- Interferon- g (CGD)
- steroids (CGD)
- stem cell transplantation
how do patients with chronic granulomatous disease (CGD) present?
pulmonary aspergillosis- halo sign on CT scan
skin infections
staph abscesses in chest, face and buttock
What are some clinically important T cell deficiencies?
- Di Georges syndrome- Lack of thymus- important for maturation of T cells - risk of cardiac abnormalities
- Severe combined immunodeficiency (SCID)- Stem cell defect- affect formation or function of T cells
- Severe combined immunodeficiency- defect in death of developing thymocytes
- severe combined immunodeficiency and Omenns syndrome- defective T cell development
